speech impediment dysarthria

• Patient Care & Health Information
• Diseases & Conditions

Dysarthria occurs when the muscles you use for speech are weak or you have difficulty controlling them. Dysarthria often causes slurred or slow speech that can be difficult to understand.

Common causes of dysarthria include nervous system disorders and conditions that cause facial paralysis or tongue or throat muscle weakness. Certain medications also can cause dysarthria.

Treating the underlying cause of your dysarthria may improve your speech. You may also need speech therapy. For dysarthria caused by prescription medications, changing or discontinuing the medications may help.

Products & Services

• A Book: Mayo Clinic Family Health Book, 5th Edition
• Newsletter: Mayo Clinic Health Letter — Digital Edition

Signs and symptoms of dysarthria vary, depending on the underlying cause and the type of dysarthria. They may include:

• Slurred speech
• Slow speech
• Inability to speak louder than a whisper or speaking too loudly
• Rapid speech that is difficult to understand
• Nasal, raspy or strained voice
• Uneven or abnormal speech rhythm
• Uneven speech volume
• Monotone speech
• Difficulty moving your tongue or facial muscles

When to see a doctor

Dysarthria can be a sign of a serious condition. See your doctor if you have sudden or unexplained changes in your ability to speak.

In dysarthria, you may have difficulty moving the muscles in your mouth, face or upper respiratory system that control speech. Conditions that may lead to dysarthria include:

• Amyotrophic lateral sclerosis (ALS, or Lou Gehrig's disease)
• Brain injury
• Brain tumor
• Cerebral palsy
• Guillain-Barre syndrome
• Head injury
• Huntington's disease
• Lyme disease
• Multiple sclerosis
• Muscular dystrophy
• Myasthenia gravis
• Parkinson's disease
• Wilson's disease

Some medications, such as certain sedatives and seizure drugs, also can cause dysarthria.

Complications

Because of the communication problems dysarthria causes, complications can include:

• Social difficulty. Communication problems may affect your relationships with family and friends and make social situations challenging.
• Depression. In some people, dysarthria may lead to social isolation and depression.
• Daroff RB, et al., eds. Bradley's Neurology in Clinical Practice. 7th ed. Elsevier; 2016. https://www.clinicalkey.com. Accessed April 10, 2020.
• Dysarthria. American Speech-Language-Hearing Association. https://www.asha.org/public/speech/disorders/dysarthria/. Accessed April 6, 2020.
• Maitin IB, et al., eds. Current Diagnosis & Treatment: Physical Medicine & Rehabilitation. McGraw-Hill Education; 2020. https://accessmedicine.mhmedical.com. Accessed April 10, 2020.
• Dysarthria in adults. American Speech-Language-Hearing Association. https://www.asha.org/PRPPrintTemplate.aspx?folderid=8589943481. Accessed April 6, 2020.
• Drugs that cause dysarthria. IBM Micromedex. https://www.micromedexsolutions.com. Accessed April 10, 2020.
• Lirani-Silva C, et al. Dysarthria and quality of life in neurologically healthy elderly and patients with Parkinson's disease. CoDAS. 2015; doi:10.1590/2317-1782/20152014083.
• Signs and symptoms of untreated Lyme disease. Centers for Disease Control and Prevention. https://www.cdc.gov/lyme/signs_symptoms/index.html. Accessed April 6, 2020.
• Neurological diagnostic tests and procedures fact sheet. National Institute of Neurological Disorders and Stroke. https://www.ninds.nih.gov/Disorders/Patient-Caregiver-Education/Fact-Sheets/Neurological-Diagnostic-Tests-and-Procedures-Fact. Accessed April 6, 2020.

Associated Procedures

• EEG (electroencephalogram)
• Electromyography (EMG)
• Lumbar puncture (spinal tap)
• Symptoms & causes
• Diagnosis & treatment
• Doctors & departments

Mayo Clinic does not endorse companies or products. Advertising revenue supports our not-for-profit mission.

• Opportunities

Mayo Clinic Press

Check out these best-sellers and special offers on books and newsletters from Mayo Clinic Press .

• Mayo Clinic on Incontinence - Mayo Clinic Press Mayo Clinic on Incontinence
• The Essential Diabetes Book - Mayo Clinic Press The Essential Diabetes Book
• Mayo Clinic on Hearing and Balance - Mayo Clinic Press Mayo Clinic on Hearing and Balance
• FREE Mayo Clinic Diet Assessment - Mayo Clinic Press FREE Mayo Clinic Diet Assessment
• Mayo Clinic Health Letter - FREE book - Mayo Clinic Press Mayo Clinic Health Letter - FREE book

Your gift holds great power – donate today!

Make your tax-deductible gift and be a part of the cutting-edge research and care that's changing medicine.

• Bipolar Disorder
• Therapy Center
• When To See a Therapist
• Types of Therapy
• Best Online Therapy
• Best Couples Therapy
• Best Family Therapy
• Managing Stress
• Sleep and Dreaming
• Understanding Emotions
• Self-Improvement
• Healthy Relationships
• Student Resources
• Personality Types
• Guided Meditations
• Verywell Mind Insights
• 2023 Verywell Mind 25
• Mental Health in the Classroom
• Editorial Process
• Meet Our Review Board
• Crisis Support

Types of Speech Impediments

Sanjana is a health writer and editor. Her work spans various health-related topics, including mental health, fitness, nutrition, and wellness.

Steven Gans, MD is board-certified in psychiatry and is an active supervisor, teacher, and mentor at Massachusetts General Hospital.

Phynart Studio / Getty Images

Articulation Errors

Ankyloglossia, treating speech disorders.

A speech impediment, also known as a speech disorder , is a condition that can affect a person’s ability to form sounds and words, making their speech difficult to understand.

Speech disorders generally become evident in early childhood, as children start speaking and learning language. While many children initially have trouble with certain sounds and words, most are able to speak easily by the time they are five years old. However, some speech disorders persist. Approximately 5% of children aged three to 17 in the United States experience speech disorders.

There are many different types of speech impediments, including:

• Articulation errors

This article explores the causes, symptoms, and treatment of the different types of speech disorders.

Speech impediments that break the flow of speech are known as disfluencies. Stuttering is the most common form of disfluency, however there are other types as well.

Symptoms and Characteristics of Disfluencies

These are some of the characteristics of disfluencies:

• Repeating certain phrases, words, or sounds after the age of 4 (For example: “O…orange,” “I like…like orange juice,” “I want…I want orange juice”)
• Adding in extra sounds or words into sentences (For example: “We…uh…went to buy…um…orange juice”)
• Elongating words (For example: Saying “orange joooose” instead of "orange juice")
• Replacing words (For example: “What…Where is the orange juice?”)
• Hesitating while speaking (For example: A long pause while thinking)
• Pausing mid-speech (For example: Stopping abruptly mid-speech, due to lack of airflow, causing no sounds to come out, leading to a tense pause)

In addition, someone with disfluencies may also experience the following symptoms while speaking:

• Vocal tension and strain
• Head jerking
• Eye blinking
• Lip trembling

Causes of Disfluencies

People with disfluencies tend to have neurological differences in areas of the brain that control language processing and coordinate speech, which may be caused by:

• Genetic factors
• Trauma or infection to the brain
• Environmental stressors that cause anxiety or emotional distress
• Neurodevelopmental conditions like attention-deficit hyperactivity disorder (ADHD)

Articulation disorders occur when a person has trouble placing their tongue in the correct position to form certain speech sounds. Lisping is the most common type of articulation disorder.

Symptoms and Characteristics of Articulation Errors

These are some of the characteristics of articulation disorders:

• Substituting one sound for another . People typically have trouble with ‘r’ and ‘l’ sounds. (For example: Being unable to say “rabbit” and saying “wabbit” instead)
• Lisping , which refers specifically to difficulty with ‘s’ and ‘z’ sounds. (For example: Saying “thugar” instead of “sugar” or producing a whistling sound while trying to pronounce these letters)
• Omitting sounds (For example: Saying “coo” instead of “school”)
• Adding sounds (For example: Saying “pinanio” instead of “piano”)
• Making other speech errors that can make it difficult to decipher what the person is saying. For instance, only family members may be able to understand what they’re trying to say.

Causes of Articulation Errors

Articulation errors may be caused by:

• Genetic factors, as it can run in families
• Hearing loss , as mishearing sounds can affect the person’s ability to reproduce the sound
• Changes in the bones or muscles that are needed for speech, including a cleft palate (a hole in the roof of the mouth) and tooth problems
• Damage to the nerves or parts of the brain that coordinate speech, caused by conditions such as cerebral palsy , for instance

Ankyloglossia, also known as tongue-tie, is a condition where the person’s tongue is attached to the bottom of their mouth. This can restrict the tongue’s movement and make it hard for the person to move their tongue.

Symptoms and Characteristics of Ankyloglossia

Ankyloglossia is characterized by difficulty pronouncing ‘d,’ ‘n,’ ‘s,’ ‘t,’ ‘th,’ and ‘z’ sounds that require the person’s tongue to touch the roof of their mouth or their upper teeth, as their tongue may not be able to reach there.

Apart from speech impediments, people with ankyloglossia may also experience other symptoms as a result of their tongue-tie. These symptoms include:

• Difficulty breastfeeding in newborns
• Trouble swallowing
• Limited ability to move the tongue from side to side or stick it out
• Difficulty with activities like playing wind instruments, licking ice cream, or kissing
• Mouth breathing

Causes of Ankyloglossia

Ankyloglossia is a congenital condition, which means it is present from birth. A tissue known as the lingual frenulum attaches the tongue to the base of the mouth. People with ankyloglossia have a shorter lingual frenulum, or it is attached further along their tongue than most people’s.

Dysarthria is a condition where people slur their words because they cannot control the muscles that are required for speech, due to brain, nerve, or organ damage.

Symptoms and Characteristics of Dysarthria

Dysarthria is characterized by:

• Slurred, choppy, or robotic speech
• Rapid, slow, or soft speech
• Breathy, hoarse, or nasal voice

Additionally, someone with dysarthria may also have other symptoms such as difficulty swallowing and inability to move their tongue, lips, or jaw easily.

Causes of Dysarthria

Dysarthria is caused by paralysis or weakness of the speech muscles. The causes of the weakness can vary depending on the type of dysarthria the person has:

• Central dysarthria is caused by brain damage. It may be the result of neuromuscular diseases, such as cerebral palsy, Huntington’s disease, multiple sclerosis, muscular dystrophy, Huntington’s disease, Parkinson’s disease, or Lou Gehrig’s disease. Central dysarthria may also be caused by injuries or illnesses that damage the brain, such as dementia, stroke, brain tumor, or traumatic brain injury .
• Peripheral dysarthria is caused by damage to the organs involved in speech. It may be caused by congenital structural problems, trauma to the mouth or face, or surgery to the tongue, mouth, head, neck, or voice box.

Apraxia, also known as dyspraxia, verbal apraxia, or apraxia of speech, is a neurological condition that can cause a person to have trouble moving the muscles they need to create sounds or words. The person’s brain knows what they want to say, but is unable to plan and sequence the words accordingly.

Symptoms and Characteristics of Apraxia

These are some of the characteristics of apraxia:

• Distorting sounds: The person may have trouble pronouncing certain sounds, particularly vowels, because they may be unable to move their tongue or jaw in the manner required to produce the right sound. Longer or more complex words may be especially harder to manage.
• Being inconsistent in their speech: For instance, the person may be able to pronounce a word correctly once, but may not be able to repeat it. Or, they may pronounce it correctly today and differently on another day.
• Grasping for words: The person may appear to be searching for the right word or sound, or attempt the pronunciation several times before getting it right.
• Making errors with the rhythm or tone of speech: The person may struggle with using tone and inflection to communicate meaning. For instance, they may not stress any of the words in a sentence, have trouble going from one syllable in a word to another, or pause at an inappropriate part of a sentence.

Causes of Apraxia

Apraxia occurs when nerve pathways in the brain are interrupted, which can make it difficult for the brain to send messages to the organs involved in speaking. The causes of these neurological disturbances can vary depending on the type of apraxia the person has:

• Childhood apraxia of speech (CAS): This condition is present from birth and is often hereditary. A person may be more likely to have it if a biological relative has a learning disability or communication disorder.
• Acquired apraxia of speech (AOS): This condition can occur in adults, due to brain damage as a result of a tumor, head injury , stroke, or other illness that affects the parts of the brain involved in speech.

If you have a speech impediment, or suspect your child might have one, it can be helpful to visit your healthcare provider. Your primary care physician can refer you to a speech-language pathologist, who can evaluate speech, diagnose speech disorders, and recommend treatment options.

The diagnostic process may involve a physical examination as well as psychological, neurological, or hearing tests, in order to confirm the diagnosis and rule out other causes.

Treatment for speech disorders often involves speech therapy, which can help you learn how to move your muscles and position your tongue correctly in order to create specific sounds. It can be quite effective in improving your speech.

Children often grow out of milder speech disorders; however, special education and speech therapy can help with more serious ones.

For ankyloglossia, or tongue-tie, a minor surgery known as a frenectomy can help detach the tongue from the bottom of the mouth.

A Word From Verywell

A speech impediment can make it difficult to pronounce certain sounds, speak clearly, or communicate fluently. 

Living with a speech disorder can be frustrating because people may cut you off while you’re speaking, try to finish your sentences, or treat you differently. It can be helpful to talk to your healthcare providers about how to cope with these situations.

You may also benefit from joining a support group, where you can connect with others living with speech disorders.

National Library of Medicine. Speech disorders . Medline Plus.

Centers for Disease Control and Prevention. Language and speech disorders .

Cincinnati Children's Hospital. Stuttering .

National Institute on Deafness and Other Communication Disorders. Quick statistics about voice, speech, and language .

Cleveland Clinic. Speech impediment .

Lee H, Sim H, Lee E, Choi D. Disfluency characteristics of children with attention-deficit/hyperactivity disorder symptoms . J Commun Disord . 2017;65:54-64. doi:10.1016/j.jcomdis.2016.12.001

Nemours Foundation. Speech problems .

Penn Medicine. Speech and language disorders .

Cleveland Clinic. Tongue-tie .

University of Rochester Medical Center. Ankyloglossia .

Cleveland Clinic. Dysarthria .

National Institute on Deafness and Other Communication Disorders. Apraxia of speech .

Cleveland Clinic. Childhood apraxia of speech .

Stanford Children’s Hospital. Speech sound disorders in children .

Abbastabar H, Alizadeh A, Darparesh M, Mohseni S, Roozbeh N. Spatial distribution and the prevalence of speech disorders in the provinces of Iran . J Med Life . 2015;8(Spec Iss 2):99-104.

By Sanjana Gupta Sanjana is a health writer and editor. Her work spans various health-related topics, including mental health, fitness, nutrition, and wellness.

• Type 2 Diabetes
• Heart Disease
• Digestive Health
• Multiple Sclerosis
• COVID-19 Vaccines
• Occupational Therapy
• Healthy Aging
• Health Insurance
• Public Health
• Patient Rights
• Caregivers & Loved Ones
• End of Life Concerns
• Health News
• Thyroid Test Analyzer
• Doctor Discussion Guides
• Hemoglobin A1c Test Analyzer
• Lipid Test Analyzer
• Complete Blood Count (CBC) Analyzer
• What to Buy
• Editorial Process
• Meet Our Medical Expert Board

Overcoming Speech Impediment: Symptoms to Treatment

There are many causes and solutions for impaired speech

• Types and Symptoms
• Speech Therapy
• Building Confidence

Speech impediments are conditions that can cause a variety of symptoms, such as an inability to understand language or speak with a stable sense of tone, speed, or fluidity. There are many different types of speech impediments, and they can begin during childhood or develop during adulthood.

Common causes include physical trauma, neurological disorders, or anxiety. If you or your child is experiencing signs of a speech impediment, you need to know that these conditions can be diagnosed and treated with professional speech therapy.

This article will discuss what you can do if you are concerned about a speech impediment and what you can expect during your diagnostic process and therapy.

FG Trade / Getty Images

Types and Symptoms of Speech Impediment

People can have speech problems due to developmental conditions that begin to show symptoms during early childhood or as a result of conditions that may occur during adulthood. 

The main classifications of speech impairment are aphasia (difficulty understanding or producing the correct words or phrases) or dysarthria (difficulty enunciating words).

Often, speech problems can be part of neurological or neurodevelopmental disorders that also cause other symptoms, such as multiple sclerosis (MS) or autism spectrum disorder .

There are several different symptoms of speech impediments, and you may experience one or more.

Can Symptoms Worsen?

Most speech disorders cause persistent symptoms and can temporarily get worse when you are tired, anxious, or sick.

Symptoms of dysarthria can include:

• Slurred speech
• Slow speech
• Choppy speech
• Hesitant speech
• Inability to control the volume of your speech
• Shaking or tremulous speech pattern
• Inability to pronounce certain sounds

Symptoms of aphasia may involve:

• Speech apraxia (difficulty coordinating speech)
• Difficulty understanding the meaning of what other people are saying
• Inability to use the correct words
• Inability to repeat words or phases
• Speech that has an irregular rhythm

You can have one or more of these speech patterns as part of your speech impediment, and their combination and frequency will help determine the type and cause of your speech problem.

Causes of Speech Impediment

The conditions that cause speech impediments can include developmental problems that are present from birth, neurological diseases such as Parkinson’s disease , or sudden neurological events, such as a stroke .

Some people can also experience temporary speech impairment due to anxiety, intoxication, medication side effects, postictal state (the time immediately after a seizure), or a change of consciousness.

Speech Impairment in Children

Children can have speech disorders associated with neurodevelopmental problems, which can interfere with speech development. Some childhood neurological or neurodevelopmental disorders may cause a regression (backsliding) of speech skills.

Common causes of childhood speech impediments include:

• Autism spectrum disorder : A neurodevelopmental disorder that affects social and interactive development
• Cerebral palsy :  A congenital (from birth) disorder that affects learning and control of physical movement
• Hearing loss : Can affect the way children hear and imitate speech
• Rett syndrome : A genetic neurodevelopmental condition that causes regression of physical and social skills beginning during the early school-age years.
• Adrenoleukodystrophy : A genetic disorder that causes a decline in motor and cognitive skills beginning during early childhood
• Childhood metabolic disorders : A group of conditions that affects the way children break down nutrients, often resulting in toxic damage to organs
• Brain tumor : A growth that may damage areas of the brain, including those that control speech or language
• Encephalitis : Brain inflammation or infection that may affect the way regions in the brain function
• Hydrocephalus : Excess fluid within the skull, which may develop after brain surgery and can cause brain damage

Do Childhood Speech Disorders Persist?

Speech disorders during childhood can have persistent effects throughout life. Therapy can often help improve speech skills.

Speech Impairment in Adulthood

Adult speech disorders develop due to conditions that damage the speech areas of the brain.

Common causes of adult speech impairment include:

• Head trauma 
• Nerve injury
• Throat tumor
• Stroke 
• Parkinson’s disease 
• Essential tremor
• Brain tumor
• Brain infection

Additionally, people may develop changes in speech with advancing age, even without a specific neurological cause. This can happen due to presbyphonia , which is a change in the volume and control of speech due to declining hormone levels and reduced elasticity and movement of the vocal cords.

Do Speech Disorders Resolve on Their Own?

Children and adults who have persistent speech disorders are unlikely to experience spontaneous improvement without therapy and should seek professional attention.

Steps to Treating Speech Impediment 

If you or your child has a speech impediment, your healthcare providers will work to diagnose the type of speech impediment as well as the underlying condition that caused it. Defining the cause and type of speech impediment will help determine your prognosis and treatment plan.

Sometimes the cause is known before symptoms begin, as is the case with trauma or MS. Impaired speech may first be a symptom of a condition, such as a stroke that causes aphasia as the primary symptom.

The diagnosis will include a comprehensive medical history, physical examination, and a thorough evaluation of speech and language. Diagnostic testing is directed by the medical history and clinical evaluation.

Diagnostic testing may include:

• Brain imaging , such as brain computerized tomography (CT) or magnetic residence imaging (MRI), if there’s concern about a disease process in the brain
• Swallowing evaluation if there’s concern about dysfunction of the muscles in the throat
• Electromyography (EMG) and nerve conduction studies (aka nerve conduction velocity, or NCV) if there’s concern about nerve and muscle damage
• Blood tests, which can help in diagnosing inflammatory disorders or infections

Your diagnostic tests will help pinpoint the cause of your speech problem. Your treatment will include specific therapy to help improve your speech, as well as medication or other interventions to treat the underlying disorder.

For example, if you are diagnosed with MS, you would likely receive disease-modifying therapy to help prevent MS progression. And if you are diagnosed with a brain tumor, you may need surgery, chemotherapy, or radiation to treat the tumor.

Therapy to Address Speech Impediment

Therapy for speech impairment is interactive and directed by a specialist who is experienced in treating speech problems . Sometimes, children receive speech therapy as part of a specialized learning program at school.

The duration and frequency of your speech therapy program depend on the underlying cause of your impediment, your improvement, and approval from your health insurance.

If you or your child has a serious speech problem, you may qualify for speech therapy. Working with your therapist can help you build confidence, particularly as you begin to see improvement.

Exercises during speech therapy may include:

• Pronouncing individual sounds, such as la la la or da da da
• Practicing pronunciation of words that you have trouble pronouncing
• Adjusting the rate or volume of your speech
• Mouth exercises
• Practicing language skills by naming objects or repeating what the therapist is saying

These therapies are meant to help achieve more fluent and understandable speech as well as an increased comfort level with speech and language.

Building Confidence With Speech Problems 

Some types of speech impairment might not qualify for therapy. If you have speech difficulties due to anxiety or a social phobia or if you don’t have access to therapy, you might benefit from activities that can help you practice your speech. 

You might consider one or more of the following for you or your child:

• Joining a local theater group
• Volunteering in a school or community activity that involves interaction with the public
• Signing up for a class that requires a significant amount of class participation
• Joining a support group for people who have problems with speech

Activities that you do on your own to improve your confidence with speaking can be most beneficial when you are in a non-judgmental and safe space.

Many different types of speech problems can affect children and adults. Some of these are congenital (present from birth), while others are acquired due to health conditions, medication side effects, substances, or mood and anxiety disorders. Because there are so many different types of speech problems, seeking a medical diagnosis so you can get the right therapy for your specific disorder is crucial.

Centers for Disease Control and Prevention. Language and speech disorders in children .

Han C, Tang J, Tang B, et al. The effectiveness and safety of noninvasive brain stimulation technology combined with speech training on aphasia after stroke: a systematic review and meta-analysis . Medicine (Baltimore). 2024;103(2):e36880. doi:10.1097/MD.0000000000036880

National Institute on Deafness and Other Communication Disorders. Quick statistics about voice, speech, language .

Mackey J, McCulloch H, Scheiner G, et al. Speech pathologists' perspectives on the use of augmentative and alternative communication devices with people with acquired brain injury and reflections from lived experience . Brain Impair. 2023;24(2):168-184. doi:10.1017/BrImp.2023.9

Allison KM, Doherty KM. Relation of speech-language profile and communication modality to participation of children with cerebral palsy . Am J Speech Lang Pathol . 2024:1-11. doi:10.1044/2023_AJSLP-23-00267

Saccente-Kennedy B, Gillies F, Desjardins M, et al. A systematic review of speech-language pathology interventions for presbyphonia using the rehabilitation treatment specification system . J Voice. 2024:S0892-1997(23)00396-X. doi:10.1016/j.jvoice.2023.12.010

By Heidi Moawad, MD Dr. Moawad is a neurologist and expert in brain health. She regularly writes and edits health content for medical books and publications.

Dysarthria: What to Know About Slurred Speech from Nerve Damage

This article will address your most pressing questions about the motor speech disorder dysarthria, including what it is, what causes it, and what treatment options are available.

By Ability Central

12 February, 2024

The motor speech disorder dysarthria is a condition in which nerve damage weakens the muscles used for speech. People with dysarthria have difficulty speaking. Their speech may be slurred, breathy, strained, or otherwise difficult to understand.

This article answers your biggest questions about dysarthria, including:

What is dysarthria?

What causes dysarthria, what are the different types of dysarthria, what are the early signs and symptoms of dysarthria, how does dysarthria affect adults, how is dysarthria diagnosed and treated, how can someone with dysarthria communicate more clearly, what are tips for listeners while talking to someone with dysarthria, where can i find help for dysarthria.

Dysarthria is a motor speech disorder. A person with dysarthria may be unable to control the muscles used for articulation, speed, and pitch of speech, generally due to nerve damage.

Dysarthria is not the same as aphasia, although each is a communication disorder, and you can have the conditions at the same time. Dysarthria is a speech impairment or speech disorder, while aphasia is an expressive language disorder or specific language impairment where the person has difficulty understanding words or putting them together in a sentence. 

A nerve, brain, or muscle disorder may cause dysarthria as the muscles that control the mouth, tongue, larynx, or vocal cords become weak or paralyzed. 

Developmental dysarthria is the result of brain damage during fetal development or at birth. Conditions like cerebral palsy, epilepsy, or carbon monoxide exposure can cause developmental dysarthria in young children. 

Acquired dysarthria is the result of brain damage later in life. Stroke , Parkinson’s disease, and amyotrophic lateral sclerosis (ALS, or Lou Gehrig’s disease) are common causes of acquired dysarthria.

Other conditions that may lead to dysarthria include:

• Brain cancer
• Brain injury
• Brain tumor
• Cerebral palsy
• Guillain-Barre syndrome
• Head injury
• Huntington's disease
• Lyme disease
• Multiple sclerosis
• Muscular dystrophy
• Myasthenia gravis
• Severe spinal injury
• Traumatic brain injury
• Wilson's disease

Dysarthria can also be a side effect of certain medications, like certain sedatives or epilepsy medications. 

Beyond categorization as developmental or acquired, dysarthria can appear as one of six types: 

• Ataxic dysarthria , caused by damage to the cerebellum, which helps coordinate muscle movement. A person with ataxic dysarthria may have trouble pronouncing letters and emphasizing the right parts of a word when speaking.
• Flaccid dysarthria,  caused by damage to the lower motor neurons. This causes speech to be breathy and nasal.
• Hyperkinetic dysarthria , caused by damage to the basal ganglia, the brain structure responsible for muscle movement. Hyperkinetic dysarthria causes fast, hyper-sounding, and often unpredictable speech.
• Hypokinetic dysarthria is also caused by damage to the basal ganglia, but with hypokinetic dysarthria, speech is slowed, monotone, or rigid.
• Spastic dysarthria , caused by damage to the upper neurons on one or both sides of the brain. This causes speech to be strained or harsh.
• Mixed dysarthria includes a mix of two or more of the other five types.

The primary symptom of dysarthria is unclear or garbled speech. Other symptoms include:

• Difficulty moving the mouth, tongue, or lips.
• Slurred speech.
• Unusually slow or unusually fast speech.
• Difficulty controlling voice volume.
• A nasal, strained, or monotone voice.
• Hesitation in talking.
• Speaking in short bursts instead of complete sentences.

Dysarthria can cause communication problems that lead to social difficulties, depression, and social isolation. It can also cause problems at work or in school, particularly in roles that require public speaking. 

Depending on the severity of the disability, people with dysarthria may qualify for certain protections under the Americans with Disabilities Act (ADA). The ADA protects people with disabilities from discrimination in the workplace, on public transit, and in public businesses. 

Ask your employer about potential accommodations for dysarthria, such as using email and text messages instead of phone calls or face-to-face meetings. 

There are many technologies that can help people with dysarthria communicate. An easy first step is a cell phone with accessibility features designed for dysarthria. Many people with dysarthria find programs like text-to-speech apps helpful for communication.

Generally, the first test for dysarthria is a physical exam from a primary care physician (PCP) or speech-language pathologist (SLP). Depending on the results of the physical exam, doctors may call for further testing to find the underlying cause of the dysarthria symptoms.

This series of tests may include:

• MRI or CT scans of the brain, head, or neck to check for physical abnormalities.
• An electroencephalogram (EEG) to check for abnormalities in brain activity.
• Electromyography to test the electrical function of the muscles and nerves.
• Blood or urine tests to see if there is an infection or inflammation.
• A spinal tap, also known as a lumbar puncture, to check for tumors or infections.
• Barium or videofluoroscopic swallow studies to test the muscles used for swallowing. 

Dysarthria treatment depends on the cause, severity, and type of dysarthria. Treatment options include:

• Speech and language therapy to improve communication and, if possible, regain normal speech.
• Speech strategies to give the best chance of being heard and understood.
• Surgery, if necessary to remove a tumor or fix an injury that’s causing dysarthria.
• Nonverbal communication strategies, like writing or sign language.
• Other accommodations and modification strategies for school or the workplace.

Much of managing dysarthria symptoms involves finding new or adaptive methods of communication. These might include:

• Using hand gestures or sign language.
• Writing by hand. 
• Typing on a computer or cell phone.
• Using text-to-speech software. 

In some dysarthria cases where the underlying condition also affects the muscles used to write and type, people with dysarthria can use tools like alphabet boards to communicate via touching and pointing. 

When speaking, many people with dysarthria find they communicate more clearly by:

• Speaking slowly.
• Using short phrases.
• Pausing between sentences to check for listener comprehension.
• Starting a conversation with a single word so the listener knows what you’re talking about. For example, saying “travel” before discussing travel logistics.

Friends, family, or coworkers of people with dysarthria can make communication easier by:

• Eliminating background noise, such as turning off the TV or moving to a quieter room.
• Facing the speaker and sitting close enough to understand visual cues.
• Making eye contact.
• Ensuring good lighting.
• Asking yes or no questions.
• Repeating what they’ve said to make sure you understand.

If you don’t understand someone with dysarthria, do not pretend you do. This can be frustrating and embarrassing for both the speaker and the listener. Instead, ask them to repeat themselves or find an alternate communication method like writing down what they’re trying to say. 

Your primary doctor is an excellent first step to receive testing for dysarthria. In addition, Ability Central has a searchable database of non-profits that can help with everything from diagnosis to treatment.

For more information on conditions that impact speech, see: 

• Aphasia and Dysphasia: Why Do People Stop Using and Understanding Language?
• Expressive Language Disorder: Symptoms, Challenges, and Treatments
• What Should I Do After a Muteness Diagnosis?
• Receptive Language Disorder: Why Can’t I Understand What People Say?

Article Type:

Keep in touch with us.

Sign up for emails to stay in the loop with Ability Central.

We care about your data security. Read our Privacy Policy.

Search form

Clinical services, what are motor speech deficits.

Acquired motor speech deficits may occur after a stroke, tumor, brain injury, or other neurological damage. These deficits result in difficulty with planning and performing speech movements. These deficits usually result in difficulty speaking. There are two different potential disorders in this area; dysarthria and apraxia of speech.

Dysarthria results from impaired movement of the muscles used for speech production, including the lips, tongue, vocal folds, and/or diaphragm. The type and severity of dysarthria depend on which area of the nervous system is affected.

A person with dysarthria may exhibit one or more of the following speech characteristics:

• "Slurred," "choppy," or "mumbled" speech that may be difficult to understand
• Slow rate of speech
• Rapid rate of speech with a "mumbling" quality
• Limited tongue, lip, and jaw movement
• Abnormal pitch and rhythm when speaking
• Changes in voice quality, such as hoarse or breathy voice or speech that sounds "nasal" or "stuffy"

Apraxia of Speech

Apraxia of speech (AOS) is a neurologic speech disorder that reflects an impaired capacity to plan or program commands in the brain necessary for directing muscles for speech movements. Individuals with apraxia of speech know what words they want to say, but their brains have difficulty coordinating the muscle movements necessary to say all the sounds in the words. As a result, they may say something completely different or make up words (e.g., "bipem" or "chicken" for “kitchen"). The person may recognize the error and try again—sometimes getting it right, but sometimes saying something else entirely. This situation can become quite frustrating for the person.

A person with apraxia of speech my exhibit one or more of the following speech characteristics:

• Difficulty imitating and producing speech sounds, marked by speech errors such as sound distortions, substitutions, and/or omissions;
• Inconsistent speech errors
• Groping of the tongue and lips to make specific sounds and words;
• Slow speech rate
• Impaired rhythm and prosody ( intonation ) of speech
• Better automatic speech (e.g., greetings) than purposeful speech
• Inability to produce any sound at all in severe cases.

Assessment and Treatment

Assessment of motor speech deficits includes the use of standardized tests or informal evaluation along with client interview. This identifies strengths and weaknesses along with outlining areas for treatment. Treatment then works to address impairments and provide strategies to support areas impacted. The focus is on functional outcomes, making an impact in quality of life and helping clients return to activities they love.

Associated Faculty

Jacqueline Daniels, MA, CCC-SLP  - Lecturer and Supervisor; Neuro Unit Coordinator Leslie Kot, MS, CCC-SLP  - Lecturer and Supervisor Mike Burns, PhD, CCC-SLP  - Senior Lecturer and Supervisor; Researcher Kelsey Leighton, MS, CCC-SLP  - Lecturer and Supervisor Shaye Kawashima, MS, CCC-SLP  - Lecturer and Supervisor Kristie Spencer, PhD, CCC-SLP - Professor and Associate Chair; Researcher

Additional Resources

American Speech-Language-Hearing Association

The Mayo Clinic

Dysarthria (difficulty speaking)

Dysarthria is where you have difficulty speaking because the muscles you use for speech are weak. It can be caused by conditions that damage your brain or nerves and some medicines. Speech and language therapy can help.

Immediate action required: Call 999 if:

• somebody's face droops on 1 side (the mouth or eye may have drooped)
• a person cannot lift up both arms and keep them there
• a person has difficulty speaking (speech may be slurred or garbled)

These can be signs of a stroke, which is a medical emergency. The symptoms of a stroke usually come on suddenly.

Check if it's dysarthria

The main symptom of dysarthria is unclear speech. This can make it difficult for you to make yourself understood.

Your speech may only be slightly unclear, or you may not be able to speak clearly at all.

Other symptoms include:

• difficulty moving your mouth, tongue or lips
• slurred or slow speech
• difficulty controlling the volume of your voice, making you talk too loudly or quietly
• a change in your voice, making it nasal, strained or monotone
• hesitating a lot when talking, or speaking in short bursts instead of full sentences

Being stressed or tired may make your symptoms worse.

Dysarthria is not the same as dysphasia, although you can have both conditions at the same time. Dysphasia, also known as aphasia , is where you have difficulty understanding words or putting them together in a sentence.

Non-urgent advice: See a GP if:

• you've noticed gradual changes to your or your child's speech and you're worried

They'll examine you and may refer you to a specialist for further tests.

Causes of dysarthria

Dysarthria is usually caused by damage to the brain or conditions that affect the nervous system. It can happen at any age.

Common causes include:

• stroke , severe head injury and brain tumours
• Parkinson's disease , multiple sclerosis and motor neurone disease
• cerebral palsy and Down's syndrome

It can also be a side effect of certain medicines, such as some medicines to treat epilepsy.

Treatment for dysarthria

If you have dysarthria, you'll usually be referred to a speech and language therapist. They'll offer therapy to help your speech and communication.

The therapy you're offered will be different depending on the cause of your dysarthria and how severe it is.

Some people may find therapy does not help their symptoms, or their speech may get worse as their condition progresses. Their therapy may focus on helping communication in other ways.

Speech and language therapy may include:

• exercises to strengthen the muscles used for speech
• strategies to make your speech easier to understand, such as slowing down when you're talking
• using communication aids, such as an alphabet board or a voice amplifier

Find out more

• Headway: communication problems after brain injury
• Stroke Association: communication tools

Page last reviewed: 17 February 2023 Next review due: 17 February 2026

How Speech Language Pathologists Treat Patients with Dysarthria

Becoming a speech pathologist offers the opportunity to address a variety of disorders and injuries that affect your patients’ daily lives and communication skills. Dysarthria is one of the more common speech disorders you’ll encounter in this profession, and it’s an ailment that has the potential to severely impact a patient’s quality of life. Successful treatment of dysarthria means you’ve been able to help your clients regain their ability to make themselves heard again, and with it, regain a sense of autonomy.

But what is dysarthria and how can you treat it as a speech pathologist? Let’s go over the different types of dysarthria, what causes it, and the available methods for helping your patients clearly communicate once again.

• Emerson College - Master's in Speech-Language Pathology online - Prepare to become an SLP in as few as 20 months. No GRE required. Scholarships available.
• NYU Steinhardt - NYU Steinhardt's Master of Science in Communicative Sciences and Disorders online - ASHA-accredited. Bachelor's degree required. Graduate prepared to pursue licensure.
• Arizona State University - Online - Online Bachelor of Science in Speech and Hearing Science - Designed to prepare graduates to work in behavioral health settings or transition to graduate programs in speech-language pathology and audiology.

What Is Dysarthria?

If you haven’t come across this literal tongue-twister of a disorder, you may be wondering “What is dysarthria and dysphagia?” Dysarthria is a motor-speech disorder, where permanent brain and/or nerve damage impacts speech-related muscles. It’s often accompanied by dysphagia, which is an impairment that affects the ability to swallow. These issues show up together frequently, since the muscles and nerves for both skills being are closely located and related in the body and brain.

Individuals with dysarthria know what they want to say, but the muscles responsible for getting the words out won’t respond correctly due to damage. These muscles either go limp and loose or become tight and rigid, causing symptoms such as:

• Slurred or indistinct speech
• Slow speech or rapid, incomprehensible speech
• Uncontrollable vocal volume (e.g., only being able to whisper or shout)
• Uneven vocal patterns
• Stiff facial muscular movement

What causes dysarthria to develop? Some causes for dysarthria include brain tumor or injury, stroke, nervous system disorders such as cerebral palsy or Guillain-Barre syndrome, certain medications such as seizure medicines. It may appear suddenly, as with brain trauma, or gradually, with progressive neurological disorders.

Dysarthria affects both adults and children, though it’s often misidentified in kids as childhood apraxia of speech, as they may only show weakness in speech-associated muscles without any other evident weakness (unlike what is common in adults). In addition, young children don’t always understand or fully cooperate with the activities necessary for accurate assessment and diagnosis.

Those who share their experience with dysarthria often feel that they’ve lost an integral part of their personality. As a  speech-language pathologist , your primary job will be helping your patients regain or hold onto speech skills using compensatory methods. At times you’ll also be called on to support dysphagia-related swallowing issues that develop alongside speech issues. You’ll probably be one of multiple professionals working to help patients improve their quality of life, and especially improve their ability to communicate with loved ones.

Types of Dysarthria

Different types of dysarthria result in varying symptoms and courses of treatment—some are accompanied by intellectual challenges, while others may present with additional speech issues like aphasia or ataxia. Knowing which types of dysarthria your patient is experiencing helps you create the best possible treatment plan.

Common types of dysarthria include:

• Ataxic dysarthria —This condition usually results from strokes or degenerative diseases. Your patient may exhibit classic, drunk-like symptoms: slurred speech, sudden increases in volume, and overall lack of coordination.
• Flaccid dysarthria —This type of dysarthria can happen after strokes, congenital disorders, ALS, cerebral palsy, tumors, MNS, or other traumas to the brain. Your patient might have low muscle tone and their speech can be breathy or nasal. Other signs include a jaw that tends to droop or hang open, and a stiff gait. They may also have swallowing difficulties.
• Hyperkinetic dysarthria —Hyperkinetic dysarthria results from diseases that attack the basal ganglia, such as Huntington’s Disease. You will notice excessive movement, strained or strangled-sounding speech, variations in volume, and changes in the rate of speaking.
• Hypokinetic dysarthria —Like its hyperkinetic counterpart, hypokinetic dysarthria also results from diseases that affect the basal ganglia, usually Parkinson’s Disease. In this case, individuals speak in short rushes with a lower volume, and at times with monopitch or monovolume. Out of all types of dysarthria, this is the only one that causes an increase in the rate of speech. You may also notice a resting tremor. Unfortunately, this form of dysarthria often comes with cognitive impairment, at times influencing treatment progress.
• Spastic dysarthria —This dysarthria is most often triggered by a stroke, although other events such as tumors, cerebral palsy, encephalitis, and primary lateral sclerosis may also cause it. You will notice spasticity, slow speech, harsh voice, weakness, and hyperactive reflexes. Depending on the root cause, the individual may show cognitive decline.
• Unilateral upper motor neuron dysarthria —This impairment most often results from stroke or neurosurgery, although tumors and traumatic brain injury are other possible causes. These patients are often easier to understand than other speech patients because only one side of the face is affected. This form of dysarthria is often only short-term.
• Mixed dysarthria —Essentially, mixed dysarthria is any combination of the above types of dysarthria. This condition tends to result from multiple strokes or diseases such as ALS, Wilson’s, and multiple sclerosis (MS). Mixed dysarthria occurs more frequently than single or “pure”, and you’ll notice symptoms from multiple categories. As such, you’ll need to tailor your treatment plan to address multiple types of dysarthria at once.

Treatment for Dysarthria

Treatment options vary among the types of dysarthria, though many therapies overlap. Some of the most common dysarthria speech and language therapy treatments include:

• Teaching the patient how to speak more slowly—this is because the brain is used to communicating verbally at a certain speed, but the muscles are no longer able to respond to that speed.
• Coaching your patient to move their tongue and lips often when not speaking, to encourage muscular redevelopment.
• Focusing on using their breath efficiently—either using more breath if their dysarthria has caused a reduction in power and volume or encouraging less breath for the reverse.
• Helping the patient learn to select alternative words and monosyllabic speech.
• Encouraging the patient to spell or over-articulate their words when they aren’t understood.
• Creating personalized communication cues for the patient and their caregiver. For example, you may have the patient start their conversation with the word “lunch,” which triggers the caregiver with a clue of what is coming next.

It’s helpful to have your patient’s family or caregiver present for some therapy sessions, as it’s important for them to learn and support the communication methods their loved one is learning so as to better understand them. For those with severe or progressive forms of dysarthria, you may also be training your patient to use augmentative and alternative communication. This includes all the types of communication that don’t involve speaking, such as writing, facial expressions, hand gestures, drawing, using photos, or even a speech-generating device.

Can Dysarthria Be Cured?

Though many dysarthria patients enjoy successful rehabilitation, it’s important to understand that depending on the severity and types of dysarthria your patient may have, they may never fully regain their pre-condition communication abilities. With treating dysarthria, your goal often isn’t to bring the damaged part of the brain back to health, but instead to find compensatory methods for the person to communicate.

That said, some types of dysarthria are easier to reverse, such as those caused by medications or by a very mild stroke.

Specializing in Treatment of Dysarthria

Though currently, you won’t find any industry certifications specific to dysarthria, there are a handful of other ways to enhance your ability to treat these patients, especially if you’re interested in deep-diving into specific neurological disorders.

One option is to pursue a Lee Silverman Voice Treatment (LSVT) LOUD certification. The  LSVT LOUD Certification training focuses on training SLP’s to work specifically with Parkinson’s patients, for whom dysarthria is often a symptom. ASHA offers continuing education credits for those taking LSVT courses, and they are now available fully online.

Because dysarthria is a neurological disorder, you may also want to consider pursuing  board certification from the Academy of Neurologic Communication Disorders and Sciences (ANCDS) . This certification tells patients and other medical personnel that you have advanced clinical expertise in these types of disorders and cements your reputation as a best-in-class practitioner.

To be eligible for this certification, you’ll need to fulfill the following requirements:

• Be a fully certified CCC-SLP
• Have five years of clinical experience with neurologic communication disorders
• Submit your CV or resume with three letters of recommendation from health care professionals familiar with your skills
• Complete the Board Certification Candidacy Application and pay applicable fees

The certification process involves submitting two case studies, giving an oral presentation, and taking part in a discussion following your presentation. The reviewers will then give you a “Pass” or notify you that your work “Does not meet standards.”

Additional options for specializing your treatment of dysarthria patients include:

• ASHA Continuing Education Webinars and E-Workshops : ASHA offers online workshops for both assessing and treating dysarthria.
• com Continuing Education Courses : This site offers continuing education credits for several courses, including ones related specifically to dysarthria. You can take an unlimited number of courses for an annual fee.
• The PROMPT Method : This therapy method is used with patients facing motor speech disorders, like dysarthria. ASHA offers CEU’s for this training.

Frequently Asked Questions About Dysarthria

Can dysarthria come and go.

Dysarthria doesn’t typically appear and then disappear, though improvement can wax and wane depending on how much the patient progresses in strengthening and controlling their facial nerves and muscles. Some causes of dysarthria, such as certain medications, may cause the condition to come and go if the patient goes back and forth on their use of the medicine.

Can anxiety cause dysarthria?

In short, no—anxiety is not a diagnosable cause for clinical dysarthria. It is extremely rare for anxiety to cause any kind of slurred speech or other verbal impairment. In the few cases that it does mimic these symptoms, they’re still wildly different than clinically diagnosed dysarthria, as the cause isn’t an actual issue with the facial muscles or nerves.

What type of dysarthria is associated with ALS?

Patients with amyotrophic lateral sclerosis (ALS) most often suffer mixed dysarthria—typically flaccid dysarthria, caused by damage to their peripheral nervous system, and spastic dysarthria, caused by damage in their motor cortex region. Symptoms of these types of dysarthria combined include slow speech, inarticulate constant pronunciation, and nasally vocalization.

Does dysarthria go away?

Dysarthria may go away with speech-language therapy, especially if it was caused by a treatable trauma, medication, or mild stroke. Some causes of dysarthria make it less likely that it will go away permanently, including degenerative neurological diseases and severe strokes.

What is apraxia and dysarthria?

Apraxia and dysarthria are both motor speech disorders. Apraxia is a brain and nervous system disorder that specifically causes an inability for patients to be able to put words together correctly. They may struggle to find the “right” word or speak words within a sentence in the wrong order, but they have no issues with their facial or vocal muscles forming and speaking verbal communication. Dysarthria, on the other hand, affects the facial muscles’ ability to form said words, rather than the brain’s ability to put words together. Dysarthria patients are physically impaired from being able to form and vocalize speech.

Be the Difference in a Dysarthria Patient’s Life

Speech-language pathologists are the key to helping dysarthria patients communicate with their loved ones again. It’s an incredibly rewarding career, and it starts with a robust education in speech-language disorders and treatment, as well as state certification to earn your clinical license.

Learn more about how to become a speech-language pathologist, including information on certification requirements, accredited SLP master’s programs, and more.

• How to Become a Speech-Language Pathologist
• Career Resources
• Both Sides of the Frenectomy Debate
• Certification
• State Licensing Overview
• Student Resources
• What is Speech-Language Pathology?
• CAA-Accredited Graduate Programs
• Directory of CSD and SLP Undergraduate Programs
• Master’s in Speech-Language Pathology
• SLP Clinical Fellowship
• SLP Thesis Track
• 2022 SLP Scholarship Guide
• 2022 Top SLP Master’s Programs
• Practice Settings
• Private Practice
• Telepractice
• Specialty Areas and Disorders
• Ankyloglossia (Tongue Tie) and Lip-Tie Issues
• Aphasia (Post Stroke)
• Apraxia of Speech
• Augmentative and Alternative Communication (AAC)
• Child Language Disorders
• Communication Competency Assessment
• Early Intervention
• Fluency Disorders
• Forensic Speech-Language Pathology
• Laryngeal Imaging
• Late Talkers
• Low-Incidence Disorders
• Multilingual Patients
• Occupational Therapy
• Otoacoustic Emissions Screening
• Patients with Autism
• Patients with Cochlear Implants
• Percutaneous Electrical Stimulation (E-stim)
• Public Health
• Rehabilitation
• Spasmodic Dysphonia
• Stuttering and Cluttering
• Swallowing and Feeding Disorders (Dysphagia)
• Transnasal Esophagoscopy and Pharyngeal/Esophageal Manometry
• Transgender Voice Modification Therapy
• Voice Therapy
• Dual Certification in SLP and Lactation Consultancy
• Continuing Education is Key to Career Versatility and Longevity in This Field
• Do You Speak with an Accent? … You Can Still Be an Outstanding SLP
• The Challenges and Rewards of Working with English Language Learners
• Some Advice on How to Approach Your Clinical Fellowship
• 4 Things a Job Description Can’t Tell You About the Profession
• 5 Things I Love Most About Being an SLP
• Your Guide to Getting Started in Telepractice
• Why Team Player SLPs are Even More Effective Than Superstars
• Why Working With the Entire Family Gets the Best Results in Kids Struggling with Speech-Language Issues

An official website of the United States government

The .gov means it’s official. Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

The site is secure. The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

• Publications
• Account settings

Preview improvements coming to the PMC website in October 2024. Learn More or Try it out now .

• Advanced Search
• Journal List
• GMS Curr Top Otorhinolaryngol Head Neck Surg

Rehabilitation of impaired speech function (dysarthria, dysglossia)

Heidrun schröter-morasch.

1 Abteilung Neuropsychologie, Städtisches Klinikum München GmbH, Krankenhaus München-Bogenhausen, München, Deutschland

Wolfram Ziegler

Speech disorders can result (1) from sensorimotor impairments of articulatory movements = dysarthria, or (2) from structural changes of the speech organs, in adults particularly after surgical and radiochemical treatment of tumors = dysglossia. The decrease of intelligibility, a reduced vocal stamina, the stigmatization of a conspicuous voice and manner of speech, the reduction of emotional expressivity all mean greatly diminished quality of life, restricted career opportunities and diminished social contacts. Intensive therapy based on the pathophysiological facts is absolutely essential: Functional exercise therapy plays a central role; according to symptoms and their progression it can be complemented with prosthetic and surgical approaches. In severe cases communicational aids have to be used. All rehabilitation measures have to take account of frequently associated disorders of body motor control and/or impairment of cognition and behaviour.

1. Definition and introduction

Oral or spoken communication belongs to the elemental functions of human existence. It is made possible by the ability to produce differentiated sounds, an acoustically perceptible way of conveying information. The function of the organs participating in speech can be compared with the construction of an organ pipe: respiration corresponds to the bellows, the larynx to the pipe itself and the articulatory organs of the vocal tract (lips, jaw, tongue, pharynx and velum) modify the air flow and the sound produced in the larynx by narrowing or closing the passage and by modifying the resonance cavities. The fast sequence of sounds during speaking requires a highly complex pattern of movement of all active muscles which has to be timed with the utmost accuracy. Speech disorders caused by sensorimotor impairments of the articulatory movements are called dysarthria. The articulatory movements of patients suffering from dysarthria are characterized by weakness, reduction in speed, malcoordination, altered muscle tone or by dyskinetic symptoms. Speech disorders caused by structural changes of the speech organs - in adults mostly after surgical and radiochemical treatment of tumors - are called dysglossia. The decrease of intelligibility, a reduced vocal stamina, the stigmatization of a conspicuous voice and manner of speech, the reduction of emotional expressivity have grave consequences: greatly diminished quality of life, restricted career opportunities and diminished social contacts.

2. Dysarthria

2.1. aetiology and pathogenesis of dysarthric disorders.

Among the causes that lead to disorders of the dysarthric type are all neurological diseases of the muscular-skeletal system; here either the motor structures of the CNS or the lower motoneuron can be affected. CNS structures in which damage is relevant are areas of the sensorimotor cortex, the cortico-nuclear tracts descending from these areas to the brain stem, the reticular formation, the polysynaptic segmental motor tracts including thalamus and basal ganglia, and the cerebellum. Dysarthria also occurs when the lower motoneuron is damaged (the nuclei of the cranial nerves V, VII, IX, X and XII or these cranial nerves themselves; the cervical nerves C1 to C8, the thoracical nerves T1 to T12 and the structures of the neuromuscular junction) or when the muscular system is injured. Speech disorders connected with isolated peripheral paresis are classified by some authors as dysglossia; for further differentiation within the terminology which is not standardized please refer to the relevant specialist literature [ 1 ], [ 2 ].

Depending on its location central damage leads to disorders analogous to motor disorders of the extremities: paresis (flaccid or spastic), akinesia and rigidity, ataxia, tremor and myoclonus, as well as different types of dyskinesia [ 1 ]. Disorders caused by central damage are very often characterized by the fact that several functions of speech production are affected: respiration, phonation, articulation and prosody (rhythm of speech, intonation and accentuation) , hence the termini "dysarthrophonia" or "dysarthrophonopneumia". If the damage is so severe that no articulatory movements are possible at all, the term used is anarthria. The most common diseases accompanied by dysarthria are listed in Table 1 (Tab. 1) .

2.2. Classification and symptomatology

Dysarthric disorders are classified either according to the location of the damage (cortical, subcortical - extrapyramidal, cerebellar, bulbar) or according to the symptoms. A classification following the symptoms seems to be of greater use for the planning of therapy. Descriptive criteria are strength of muscle, tone of muscle (hypertonic, hypotonic) and the kinematics of the movements (range, speed and accuracy).

Spastic dysarthria : This is caused by spastic paresis due to lesions of the upper motoneuron and accompanied by muscular hypertonia as well as by a deterioration of strength and precision. Reflectory movements associated with coughing, choking and swallowing are usually unaffected (dissociated paresis, also see Table 3, as well as movements associated with emotional expression like laughing and crying. Auditory characteristics include a strained, harsh voice quality, a shift of the tongue's articulation zones backwards leading to an imprecise production of consonants, hypernasality (caused by spasticity of the palatine arches or by a weakness of the velum's elevators) as well as slow and monotonous speech. Spastic dysarthria is the most common type of dysarthria resulting from severe closed head trauma.

Rigid hypokinetic dysarthria : Damage is localized mainly in the basal ganglia. In the presence of an increased background activity the muscle resistance to passive stretch is increased; akinesia and bradykinesia are to be found. The voice is weak and breathy, the articulation imprecise, the rate of speech may be increased, sounds and syllables iterated. The most common cause is Parkinson's disease of which this speech disorder counts among the early symptoms. It can also be accompanied by a tremor of the voice, in consequence of a tremor of the vocal folds.

Ataxic dysarthria : Typically, muscular movements are characterized by overshoot or undershoot (dysmetria); motor efforts cannot be stably maintained. This disorder is caused by damage to the cerebellum and connected areas. As to articulation, there is a tendency toward lenisation and fortisation, the phonation is hoarse and strained, with devoicing, pitch breaks and an instability of pitch as well as loudness. Speech is produced in a syllabic way and at a lower speed. The most common causes are inflammatory and degenerative diseases of the cerebellum, but also cerebrovascular damage and trauma in this area .

Dyskinetic and dystonic types of dysarthria : Inappropriate muscle activation patterns with hypertonic contractions and uncontrolled movements can also affect the muscles involved in speech production. This can lead to varying impairments of voice quality, to interruptions in speech flow or to involuntary vocal output as observed in Huntington's disease or in athetosis. Spasmodic dysphonias (where the larynx muscles are affected) and oromandibular dystonia result from focal dystonia. Tremor and myoclonus, which can cause phonatory as well as articulatory disorders, belong to the group of repetitive hyperkinesias with a variety of frequency, amplitude and acceleration patterns [ 3 ].

Flaccid dysarthria : This is caused by a flaccid paresis following damage to the lower motoneuron (nuclei of the cranial nerve in the brain stem, peripheral nerves), but can also be observed after suprabulbar lesions. Symptoms are reduced muscle tone, loss of voluntary and reflectory functions, muscular atrophy and possibly fasciculations often concerning single muscles only. The damage results, depending on its localization, in a weak, breathy voice, hypernasality, imprecise consonants and a decrease in speech rate. The most frequent cause of flaccid dysarthria is damage in the brain stem (bulbar symptoms), e.g. in cases of amyotrophic lateral sclerosis. But also peripheral nerve damage as occurs in polyneuropathy or tumors or damage of the neuromuscular junction as occurs in myasthenia or muscular diseases can lead to the symptoms of flaccid dysarthria.

Mixed types : As a consequence of extended damage, e.g. in the case of encephalitis disseminata, after closed head trauma or cerebrovascular diseases frequently there can be seen a combination of several types of dysarthric disorder.

3. Dysglossia

3.1. aetiology and pathogenesis of dysglossia.

Speech disorders which arise from damage to the peripheral structures involved in speaking are called dysglossias. They can be caused by many factors: by congenital malformations (in particular craniofacial malformations including clefts of the palate, jaw and lips and oro-mandibulo-facial malformations accompanying various syndromes [ 4 ]), by acquired dental defects and trauma, but above all by the defects and tissue alterations caused by surgical and radio-chemotherapeutic treatment in the head and neck region. As opposed to dysarthrias often only specific areas of phonation and articulation are concerned. Depending on the damage the results can range from incomplete realizations of sounds to total failure of functions. Congenital malformations most frequently lead to characteristic adaptations.

3.2. Classification and symptomatology

According to the localization of the damage dysglossias can be classified as labial, dental, lingual, palatal, velopharyngeal and nasal, with impairments of sound production at all places of articulation, but also with impairments of phonation. According to Leonard et al. [ 5 ] anterior tongue resections are accompanied mainly by defective consonants, posterior resections mainly by defective vowels. The probability of articulatory deterioration caused by resections of tumors from the oral cavity or from the oropharynx varies a lot [ 6 ]: base of tongue 100 %, mandible 87,5 %, floor of mouth 81 %, tongue 72,7 %, lips 28,6 %, tonsils 27,3 %. To what degree the functions are impaired also depends on the techniques of reconstruction. With local flaps the speech intelligibility is least impaired, with transplants from the small intestine, myocutaneous or fasciocutaneous transplants the degree of impairment is higher [ 7 ]. Koppetsch and Dahlmeier have shown in a study in 2004 [ 8 ] that patients with tumors of the tongue or of the floor of the mouth suffered from a deterioration of all oral functions like chewing, swallowing and speaking as well as impairment of tactile and gustatory sensitivity after tumor resection and reconstruction, but particularly after the start of radio-chemotherapy. Defects of the palate and the maxilla very often create connections between nasal cavities, paranasal sinuses and oral cavity which leads to a strong open nasalization as well as to severe swallowing disorders. It should also not be forgotten that tumor resection and radiation can cause secondary damage of lower cranial nerves with corresponding impairments of speech, which may appear immediately after the treatment, but possibly only years or even decades later [ 9 ].

4. Diagnosis of speech disorders

Two aspects have to be considered: (1) The registration of physiological parameters (movement, strength, EMG) may give information about the disorder's underlying mechanisms and so may lead to conclusions about type, degree and localization of the disease. (2) Measuring auditory and acoustic characteristics enables us to define the functional effects of deficiencies in speech motor control and so to describe the impairment of communication. Both components are essential for differential diagnosis and for establishing guidelines for therapy [ 10 ].

The clinical examination of speech disorders should include the following steps [ 11 ]:

- Anamnesis

- Auditory examination including intelligibility test

- Inspection and palpation of speech organs including endoscopic examination of velopharynx and larynx

- Acoustic analysis of speech sound

- Aerodynamic methods of measurement

- Registration of further physiological parameters

- If appropriate examination with imaging techniques

Anamnesis should establish:

- Primary disease, former treatment, medication

- In cases of cerebral damage: Degree, localization

- Date of damage, improvement/deterioration since

- Effects of the speech disorder on daily life (social contacts, work, leisure)

- Speech disorders before the actual disease; abnormalities in speech development

- Possibly associated symptoms: Malsensations, pain, urge to clear throat, chewing and swallowing disorders, impairment of gustatory sensitivity

- For treating dysarthria it is absolutely necessary to find out about possibly associated neurological and neuropsychological disorders (Table 2 (Tab. 2) )

Disorders of this kind can influence the ability for oral communication and have to be taken into consideration in therapy. In cases of acute cerebral damage vital functions like respiration, circulation and ingestion are often initially impaired, which requires long-term intubation, tracheotomy and gavage. These often lead to mechanical damage to the voice and speech organs; this has to be distinguished from the symptoms caused by cerebral damage.

Auditory examination

Auditory examinations register the effects resulting from impairment of speech respiration, phonation, articulation and prosody. These examinations serve as a basis (1) for systematic phonetic analysis and (2) for identifying the aspects of the speech disorder which are relevant for communication. The symptoms are tested in a variety of tasks and classified with the help of evaluation scales [ 12 ]. The German version of the "Frenchay Dysarthria Test" [ 13 ] offers a standardized procedure which combines visual and auditory observation of dysarthric symptoms, although the patho-physiological causes and the functionally relevant symptoms are not sufficiently taken into account.

One of the decisive parameters for the ability to communicate is intelligibility. A reliable and valid procedure to measure intelligibility is the computer-based "Münchner Verständlichkeitsprofil (MPV, Munich intelligibility profile)", which provides an overall value for intelligibility as well as specific information relevant for therapy [ 14 ].

Inspection and palpation of the speech organs as part of a neurologically oriented phoniatric examination

Inspection and palpation are central elements in the examination of speech disorders. They allow a qualitative evaluation of the laryngeal and articulatory motor control disorders. Examination includes the following points [ 15 ]:

- Structural changes (inflammation, defects, scars, changes in the mucosa)

- Characterization of the sensorimotor disorder according to changes in muscle tone, reduction in amplitude and speed of movement, signs of hyperkinesia and apraxia; examinations are carried out during rest as well as during voluntary and reflectory action. The most important criteria for the distinction between central and peripheral paresis are listed in Table 3 (Tab. 3) .

- Impairment of sensibility and reflectory reaction

- Signs of functional maladaptation (e.g. hyperadduction of the larynx)

Visual and palpatory examination applies to the muscles of the neck and the floor of the mouth, the lips, jaw, tongue and velum. Among the methods to investigate the velopharynx and larynx are laryngoscopy, stroboscopy, and fiberendoscopy for the endonasal examination of velum, pharynx and larynx. Video recording permits the analysis of movement in slow motion, serves to document the examinations as well as to evaluate therapy and can be used for biofeedback therapy [ 16 ].

Examinations with high speed cameras, 3D-endoscopy, kymography, ultrasound and electroglottography can be very useful to judge disorders of motor control and to achieve differential diagnosis of structural impairments, peripheral nerve lesions and central disorders of voice function.

Measurement of acoustic parameters

The analysis of the speech signal resulting from the articulatory movements allows objective description of qualitative changes in the realization of sounds as well as a quantification of symptoms relevant for communication, like reduction in movement speed, changes in pitch or impaired fluency.

Aerodynamic methods of measurement register pressure and air flow during speaking. Separate measurements of oral and nasal air flow allow classification of impairments in velar function [ 17 ].

Registration of further physiological parameters

Measuring electrical muscle activity (EMG) is of particular importance for distinguishing peripheral paresis (with pathological spontaneous activity) from central paresis.

Gröne 2002 [ 18 ] describes in detail several methods which are also used clinically for examining specific articulatory movements: Palatography allows the contact between tongue and palate to be assessed. Electropalatography describes moreover in detail the temporal and spatial aspects of the contacts between tongue and hard palate during speaking. Electromagnetic articulography allows analysis of the movements of tongue, pharynx and velum.

Imaging techniques

By means of ultrasound structural changes can be detected and individual movement patterns can be documented. Cineradiography or videofluoroscopy of the speech process allow a differentiated evaluation of motion patterns, particularly of their coordination, but because of the exposure to radiation there must be a clear indication justifying its use. Nuclear magnetic resonance imaging (NMRI) is also suitable for showing structural changes and analyzing movements, although the temporal resolution in the latter case is still unsatisfactory.

The main goals in treating speech disorders are an improvement of the speech motor output and an improvement of the communicative abilities in order to reduce the effects of the disablement on everyday life. When judging the potential for rehabilitation and establishing an attainable goal of therapy, the following prognostic factors have to be taken into account:

(1) Kind and degree of damage to the brain, period of time passed since the beginning of the disease and the development of the disease, progression or stability. In cases of tumor disease further structural changes have to be considered: scars or tissue changes after radiation and chemotherapy.

(2) Multimorbidity and unfavorable psychosocial conditions frequently reduce the therapeutic chances for older patients.

(3) It must be guaranteed that qualified therapists are accessible to the patient.

(4) Personality and psychosocial surroundings can have decisive influence on the course of the therapy.

(5) Associated neuropsychological disorders like impairment of cognition, language and perception as well as changes in behaviour, e.g. subdued incentive, influence course and result of therapy.

The principles of treating speech disorders have been already formulated by Darley et al 1975 [ 19 ]:

(1) An early start of treatment aims to avoid maladaptation, e.g. hyperactivity of remaining muscle functions; in case of progressive diseases the intelligibility is to be maintained as long as possible.

(2) By acquiring compensatory strategies, e.g. a reduced speech rate, it should be possible to optimize the use of remaining functions.

(3) The patient should aim to acquire voluntary control of speech in different situations of daily life, at work and in private life.

(4) Necessary modifications of speech behaviour cannot be attained without adequate self-perception; this forms an essential part of therapy.

(5) The speech motor systems respiration - phonation - articulation influence one another. For this reason it is essential to find out in diagnosis which system is most affected; this should be the initial focus of treatment.

(6) The compensatory techniques of speech and communication to be acquired have to be acceptable for the patient and his surroundings.

(7) The patient's motivation has to be aroused and kept up by making him understand the nature of his disorder and the principles of its treatment.

The therapeutic methods follow the general principles of rehabilitation, restitution - compensation - adaptation:

Restitution means restoring impaired functions, e.g. strengthening paralyzed muscles or re-achieving tongue motility impaired by scar tissue. Compensation means improving functions by substitution strategies or by the use of remaining abilities, while the disorder continues. Adaptation means adjusting to the disorder mainly by a change of communicative behaviour, e.g. avoiding background noise in conversations; in severe cases alternative means of communication have to be used.

Following Duffy 1995 [ 20 ] therapeutic approaches to speech disorders can be classified into (1) behaviour-modifying methods, (2) prosthetic intervention and (3) medical procedures.

5.1. Functional therapy: Behaviour-modifying methods and instrumental aids

Modification of behaviour means in this context influencing one or several speech motor functions, as well as linguistic or communicative behaviour. In the specific treatment of speech motor control there are direct and indirect methods [ 21 ]:

Indirect methods of treatment: Indirect approaches mainly aim at a restoration of the impaired function and correspond to the principle of restitution . The training tasks have no phonetic content, but rather are located "outside" the speech process and are based on the principles of physiotherapy, adapted to the specific conditions of the speech muscle system. Among those methods are relaxation techniques, correction of posture, reversal of pathological reflexes, stimulation (sensory stimulation, passive and active movement) and specific exercises aiming at an influence on muscle tone, as well as on the strength, amplitude, accuracy and smoothness, selectivity and symmetry of movement, and also aiming at voluntary efforts. Indirect methods are used in all speech motor systems (respiratory movements - laryngeal function - articulatory movements) and can be effectively supported by instrumental aids and feedback procedures: control of expiratory volume velocity can be trained by visual feedback with pneumotachometric parameters, abdominal and thoracic respiratory movement can be trained by feedback with kinematic parameters. The phonation can be visualized by the registration of loudness and pitch (visipitch), also the coordination between expiration and voice can be visualized, so the patient can recognize and influence it. As to the speech musculature EMG-feedback devices have proved very helpful for the reduction of muscle tone as well as for the improvement of selective motility of those muscles accessible from outside. The improvements attained by indirect methods of therapy are not automatically transferred onto speech behaviour. Special transfer exercises are necessary.

Direct methods of treatment: Here the speech motor system itself is modified; this includes all exercises with phonetic and linguistic content. This mainly leads to behaviour modifications following the principle of compensation , which means that a continuing disorder is improved by substitution strategies. An example is the treatment of patients with Parkinson's disease who suffer from a weak voice caused by laryngeal hypoadduction; there are attempts to increase the sound volume of their voice by means of specific exercises aiming at variation of respiratory depth and of subglottal pressure, combined with tension in the whole body as well as with exercises for pressing and pushing ( Lee Silverman Voice Treatment [ 22 ]). Direct therapeutic methods can also include instrumental aids and biofeedback techniques like speech delayer or tactile board for support of rhythmization. By means of video-endoscopy with fiberoptics the articulatory movements of the velum or larynx can be visualized [ 16 ], [ 23 ].

Indirect and direct approaches complement each other and are therefore usually applied side by side. Attention should always be paid to the hierarchy of the main disorders in each motor sub-system as well as to a reduction of compensatory maladaptations (e.g. laryngeal hyperadduction, overarticulation, exaggerated speech rate). A detailed discussion of specific methods of treatment for each speech motor system can be found in Vogel 2002 [ 21 ].

In therapy, besides the treatment of speech disorders the patient should also acquire communicative strategies adapted to his intelligibility and stamina (e.g. short sentences, accurate planning, precise content). Another important part of therapy consists in working out together with the patient and his family suitable correction techniques.

Alternative means of communication have to be used when sufficient ability for oral communication cannot be attained. There are a great variety of devices from simple letter boards to writing computers and complicated multimedia systems; they all have to be adapted individually and require specific training to be used efficiently.

5.2. Prosthetic intervention

A simple prosthetic device that is helpful for mandibular instability consists of a small plastic block (bite block) which is wedged between the teeth and so inhibits undesired movements of the lower jaw and helps to keep the opening angle of the jaws small.

Prostheses are applied particularly in cases of extensive defects of the tongue, the floor of the mouth, upper and lower jaw and velopharynx or in cases of severe functional disorders of the tongue and velopharynx caused by paralysis. The so-called obturator prosthesis allows contact between tongue and palate even in cases of tongue atrophy or missing substance in tongue and palate; sound production is thus made possible or easier. Moreover any opening between oral and nasal cavitiy can be closed, so no air is lost and oral pressure can be adequately built up (Figure 1 (Fig. 1) ).

A prosthetic enlargement of the alveolar ridge is also a measure that can improve function after partial resection of the tongue. Of particular significance are prostheses of the velum; velar function in regulating air flow plays a central role in connection with the rest of the articulatory functions. An impaired closure of the velopharynx not only has severe effects on resonance including hypernasality, but may also affect the kinematics and coordination of other articulators, of phonation and respiration and may lead to pronounced functional maladaptations. Thus the treatment of velopharyngeal closure defects is of great importance. The results of behaviour-modifying therapeutic approaches are often unsatisfactory, particularly in the treatment of bilateral paresis of the velum, a frequent symptom after severe closed head trauma. But also defects of the velopharynx after tumor resection and radiotherapy lead to severe impairments affecting the motor function systems mentioned above. The velar prosthesis ("palatal lift") therefore belongs to the most successful and effective methods of treating dysarthria [ 20 ]. Vogel and Sauermann [ 24 ] made decisive advances in the further development of its technical construction, adaptation to the patient's palate and subsequent therapy. In order to lift and possibly extend the velum a covered metal plate shaped like the soft palate is fixed to the teeth like a brace; towards the back the plastic covering widens into a thin elastic blade. This lifts the velum and closes most of the velopharyngeal passage (Figure 2 (Fig. 2) ).

The aerodynamic conditions during speaking are immediately improved (less air is lost, intraoral pressure can be built up again); this frequently contributes to normalizing the other speech motor abilities often making effective training possible for the first time. Disadvantages and risks (sensation of foreign body, gag reflex, impairment of nasal respiration, increased salivation, swallowing difficulties) have to be met by patient adaptation. An intensive accompanying exercise therapy of sufficient duration (at least 6 weeks) is obligatory. Early intervention is desirable, but even in cases of velopharyngeal insufficiency having persisted for years success can be excellent. For many patients the prosthesis could be shown to have a stimulating effect, facilitating active raising of the velum so that in the end the prosthesis did not have to be worn any more.

5.3. Surgical procedures

In cases of dysarthria surgical methods for voice improvement are rarely indicated. They are appropriate though in cases of peripheral paresis of the vocal fold caused by lesion of the nucleus of the vagal nerve with excavation of the vocal fold and loss of glottal closure. Above the glottis there are a number of surgical procedures that can improve sound production depending on the localization and centre of the disorder; e.g. velopharyngeal insufficiency can be improved by plastic surgery of velopharynx or pharynx. Velopharyngoplasty (connection between velum and back wall of the pharynx in the shape of cranially or caudally pedunculated flaps) can be successful if residual contraction of the lateral and posterior muscles of the pharynx is still present. But these are affected by central lesions just as often as the velum itself. Because of shrinking of the flaps and formation of scar tissue the success of an operation often does not last. If the velum still has a residual but insufficient lifting function, attempts can be made to create velopharyngeal contact by augmenting the back wall of the pharynx with body tissue or artificial material. In cases of oropharyngeal defects after tumor treatment a surgical reconstruction of areas relevant for articulation (lower jaw, floor of the mouth, tongue, palate, pharynx) can lead to an improvement of speech ability. Surgical loosening of scar structures can be considered when motility is impaired by them.

Currently, the only medication of any significance is injection of botulinum-toxin in cases of severe spasticity of the orofacial muscles or in cases of focal dystonia, in particular spasmodic dysphonia.

All prosthetic and surgical measures require close cooperation between speech therapist, phoniatrician, dentist/maxillofacial surgeon and ENT specialist.