Dysarthria

Dysarthria is a speech disorder caused by damage to the brain or nerves: the muscles used for speech become weak, slow, imprecise or poorly coordinated, so speech sounds slurred, slow, quiet or hard to understand.⁠^1,2 It affects speech only, not language or thinking.⁠^1,3 A speech-language pathologist treats it with practice that makes speech clearer and strategies that make it easier to understand (see speech therapy for adults); in Parkinson’s disease, an intensive loudness program improved voice-related quality of life for a year in a trial of 388 people.⁠⁴ Sudden slurred speech is a stroke sign: call 9-1-1.⁠⁵

What is dysarthria?

Dysarthria is a speech disorder caused by damage to the brain or to the nerves that control the speech muscles. Those muscles become weak, slow, imprecise or poorly coordinated, so speech can sound slow, slurred or hard to understand.⁠^1,2 It can affect breathing for speech, the voice, resonance, articulation and the rhythm of speech, and it makes speech less intelligible, less natural, or both.⁠¹

Dysarthria affects only the production of speech. Language, meaning understanding and choosing words, is a separate system, and dysarthria itself causes no difficulty thinking, remembering or retrieving words.⁠^1,3 It can be present from birth or acquired at any age after an injury or illness, and how severe it sounds does not necessarily match how much it limits a person’s life.⁠¹ It is diagnosed and treated by a speech-language pathologist (SLP); speech therapy explains what SLPs do.

How common is dysarthria?

Dysarthria is common in neurological disease. ASHA’s estimates, each counting people with that condition:

Single studies fall within those ranges: 44% of 151 people with a first ischemic stroke in a Belgian stroke unit, and 42% of 221 people after a first ischemic stroke in Toronto.⁠^6,12

What causes dysarthria?

Anything that damages the brain or the nerves to the speech muscles can cause dysarthria, and depending on the cause it may come on suddenly or develop slowly.⁠^2,13 The causes ASHA and MedlinePlus list:

• Stroke, from a blocked or a bleeding blood vessel.⁠¹
• Traumatic brain injury, including chronic traumatic encephalopathy.⁠¹
• Degenerative diseases: Parkinson’s disease, ALS, progressive supranuclear palsy, multiple system atrophy, corticobasal degeneration and Huntington’s disease.⁠¹
• Cerebellar ataxias, such as Friedreich’s ataxia and spinocerebellar ataxia; dysarthria is the speech problem most often reported in the hereditary ataxias.⁠^1,14
• Multiple sclerosis and other inflammatory conditions, such as encephalitis and Guillain-Barré syndrome.⁠¹
• Neuromuscular disease, such as myasthenia gravis, a chronic disease that weakens the voluntary muscles and can impair speech and swallowing.⁠^1,15
• Conditions present from birth, such as cerebral palsy.⁠¹
• Tumors and surgery: tumors of the brain, cerebellum or brainstem, injury during brain surgery, and surgery for head and neck cancer that removes part or all of the tongue or voice box.⁠^1,13
• Infections and toxins, among them COVID-19, botulism, carbon monoxide poisoning, heavy metals and lithium toxicity.⁠¹
• Medicines, alcohol and drugs: side effects of medicines that act on the brain, such as narcotics, phenytoin or carbamazepine, and intoxication with alcohol, drugs or medicines.⁠¹³
• Poorly fitting dentures.⁠¹³

What are the types of dysarthria?

SLPs classify dysarthria by where the nervous system is damaged, because each site produces a recognizable pattern; the patterns overlap, and the type can be hard to pin down.⁠¹

Typical pairings: Parkinson’s disease produces hypokinetic dysarthria; ALS is expected to produce a mixed spastic–flaccid dysarthria; and after a stroke the most common type is unilateral upper motor neuron dysarthria, found in 52% of the people fully assessed in one stroke unit.⁠^4,6,17 Weakness of the face, lips and tongue goes with flaccid and spastic dysarthria but not with ataxic dysarthria, so weakness is not the problem in every type.⁠¹⁷

What are the signs and symptoms of dysarthria?

The signs depend on the type, but people with dysarthria and their families usually notice:

• slurred or mumbled speech, or speech that sounds poorly pronounced;⁠^2,13
• speaking too slowly or too fast, or in short rushes;⁠^1,2
• speaking too quietly or too loudly, or a voice that sounds hoarse, breathy or strained;⁠^2,13
• a nasal or stuffy sound;⁠¹³
• a changed rhythm, or speech that sounds robotic or choppy;⁠^2,13
• difficulty moving the tongue, lips and jaw, drooling, and problems chewing or swallowing.⁠^2,13

Speech is often harder to understand when the person is tired, and in some conditions it changes with the time of day or the medication schedule.⁠^1,2 In ALS, speaking itself can be tiring, especially later in the day.⁠¹⁸

Is sudden slurred speech an emergency?

Yes. Slurred or strange speech that starts suddenly is one of the warning signs of a stroke, and the right response is to call 9-1-1 at once.⁠^5,19 The quick test is part of B.E. F.A.S.T.: ask the person to repeat a simple phrase and listen for slurred or strange speech.⁠⁵

Strokes in the back of the brain can cause slurred speech together with vertigo, imbalance, double vision, headache or vomiting.⁠²⁰ The consumer advice from ASHA’s affiliate is the same for any sudden change in speech or communication: call 911.⁠²

For dysarthria that is already known, contact a provider about coughing or choking, or about fever, chills, chest pain, shortness of breath or other symptoms of pneumonia.⁠¹³

How is dysarthria diagnosed?

A speech-language pathologist diagnoses dysarthria, measures how severe it is and describes it; a neurologist looks for the cause if it is not already known.⁠¹

What does the speech evaluation involve?

• History: how speech has changed, the medicines you take, and whether speaking takes more effort when you are tired, at certain times of day or with your medication schedule.⁠¹
• A cranial nerve exam of the face, mouth, palate and larynx, looking at strength and symmetry.⁠¹
• Speech tasks: holding a vowel to judge breath support and the voice, and repeating syllables quickly to judge the speed and regularity of the jaw, lips and tongue.⁠¹
• Listening to conversation and reading, including 2 to 4 minutes of reading or talking aloud to see whether speech deteriorates.⁠¹
• Intelligibility: the percentage of words a listener understands, and how many understandable words come across per minute.⁠¹
• Language and swallowing, partly to tell dysarthria from aphasia.⁠¹

What tests look for the cause?

When the cause is unknown, the doctor may order an MRI or CT scan of the brain or neck, nerve conduction studies and an electromyogram, and blood tests for toxins or vitamin levels; a laryngoscopy, a look at the voice box, may also be done.⁠¹³ The SLP may also refer you to a prosthodontist to see whether a palatal lift could help.⁠¹

What is the treatment for dysarthria?

Treatment is speech therapy with an SLP, aimed at restoring function to make speech clearer, at compensating so that communication works even when speech does not, or both.⁠¹ Not everyone with dysarthria needs treatment, and in a progressive disease the goal may be to preserve function or slow its decline.⁠¹

How does therapy make speech clearer?

• Breathing and posture: sitting upright for breath support, phrases matched to the breath, and expiratory muscle strength training with a pressure threshold device.⁠¹
• Voice: loudness programs such as LSVT LOUD, which targets high vocal effort, and Pitch Limiting Voice Treatment, which raises loudness without raising pitch.⁠¹
• Rate: slowing down with hand tapping, a pacing board, a metronome or delayed auditory feedback.⁠¹
• Articulation: deliberately exaggerated, clear speech.⁠¹
• Resonance: for speech that is too nasal, a palatal lift, a removable appliance worn in the mouth, or surgery by referral.⁠^1,18

How does therapy make communication work when speech is unclear?

Compensation works through the speaker’s strategies, the listener’s skills and the setting.⁠¹ Speakers learn to tell people they have a speech difficulty, to gain attention and name the topic before speaking, and to start with a keyword; listeners learn to face the speaker, cut background noise and repeat back the part they understood (see tips for listeners).⁠^1,2 When speech is not enough, AAC adds to it or replaces it.⁠¹

The underlying condition is treated by the doctor: ASHA lists medicines for the neurological condition, and surgery to the palate or throat, among the options an SLP may refer you for.⁠¹

Does speech therapy help dysarthria?

For Parkinson’s disease, yes: in the largest trial, an intensive loudness program improved voice-related quality of life for at least a year.⁠⁴ After a stroke or brain injury, the trials are too small to say which therapy works best, and the Cochrane review’s advice is to keep receiving rehabilitation according to clinical guidelines.⁠³

Does therapy help dysarthria after a stroke or brain injury?

The Cochrane review found only five small randomized trials, with 234 participants. Its main analysis found no evidence in favor of therapy over control, and a short-term improvement in tongue and lip movement that it judged unreliable; it found no adequately powered trial and concluded that the evidence is not yet robust enough to guide practice, which is a statement about the trials, not proof that therapy fails.⁠³

The largest trial, ACT NoW, randomized 170 people within two weeks of a stroke with aphasia, dysarthria or both, either to communication therapy (an average of 22 contacts over 13 weeks) or to visits from paid visitors without therapy. At six months the difference was not significant: therapy added nothing beyond everyday communication in the first four months.⁠²¹

Early recovery is common anyway. In one stroke unit, 46% of 151 patients had dysarthria on admission, and half of them recovered completely within a week.⁠⁶ A 2026 trial of 73 people found speech therapy by smartphone app no worse than workbook therapy at improving intelligibility after a stroke, with 60 minutes of practice a day, 5 days a week, for 4 weeks; the participants had no aphasia or cognitive problems, and three of the authors work for the app’s developer.⁠²²

Does therapy help dysarthria in Parkinson’s disease?

The strongest evidence is for LSVT LOUD. The PD COMM trial in the UK randomized 388 people with Parkinson’s disease and dysarthria to LSVT LOUD, to the usual NHS speech therapy, or to no speech therapy. At three months, people who had LSVT LOUD reported less voice handicap than both other groups, and the benefit over no therapy persisted through 12 months; usual NHS therapy, given at a much lower intensity, did no better than none.⁠⁴

Its limits: participants knew which treatment they had, most had early Parkinson’s with mild speech problems, and the trial closed early during COVID-19. LSVT LOUD caused more side effects, mostly minor and temporary vocal strain, with no serious adverse events, and the authors stress the result is not evidence against every form of usual therapy at every dose.⁠⁴

Earlier trials point the same way. In a US trial of 64 people, LSVT LOUD made voices louder at 1 and 7 months than articulation therapy or no treatment, and only LSVT LOUD kept its gains in communicative effectiveness at 7 months; blinded listeners also understood more words after it.⁠^23,24 Those studies were run by the program’s developers, several of whom work for or consult for the company that owns it.⁠^23,24 An older trial of 33 people found the louder voices maintained two years later.⁠²⁵ Two Cochrane reviews from 2012, written before these trials, found the evidence then too thin to support or refute speech therapy in Parkinson’s.⁠^26,27

Other programs: SPEAK OUT!, 12 sessions over 4 weeks followed by group sessions, improved loudness in a study without a randomized control group, run with the program’s own organization.⁠²⁸ Remote personalized speech therapy in the Netherlands, 214 people over 8 weeks, improved communication-related quality of life but not overall quality of life.⁠²⁹

Does therapy help dysarthria in the hereditary ataxias?

A Cochrane review found 14 trials, 13 of them of drugs and none of traditional speech therapy, and too little evidence to judge any treatment for speech in the hereditary ataxias.⁠¹⁴

What is LSVT LOUD?

LSVT LOUD (Lee Silverman Voice Treatment) is an intensive speech program for Parkinson’s disease that trains people to speak with more vocal effort, so they are louder.⁠¹ In the PD COMM trial only therapists trained in it delivered it.⁠⁴

The standard course is 16 one-hour sessions in a month, four days a week for four weeks, with homework of 10 minutes once a day on therapy days and 15 minutes twice a day on other days.⁠^23,24 In PD COMM the sessions were 50 minutes, face to face or remote.⁠⁴

Each session opens with the same exercises, holding a vowel in a good-quality, loud voice for as long as possible, pitch glides, and reading 10 phrases the person says every day; the rest of the session moves, week by week, from words to phrases, sentences, reading and conversation, and there is an assignment to use the louder voice in a real conversation.⁠²³

Why loudness: a quieter voice is among the first and most pervasive speech changes in Parkinson’s, and speech generally does not respond to medication or brain surgery alone; dysarthria can even worsen after subthalamic stimulation surgery.⁠^4,23 LSVT LOUD can also be done by video at home: in a trial of 31 people, online treatment was as good as in person.⁠³⁰

Do mouth and tongue exercises help dysarthria?

Exercises that strengthen the tongue, lips and jaw without speaking have not been shown to improve speech. A systematic review of 15 studies found insufficient evidence for or against them, and a small randomized trial after stroke found that adding them to standard therapy did not appear to change outcomes.⁠^7,8 The ALS Association advises against them for the speech changes of ALS.⁠¹⁸ And weakness is not the problem in every type: it goes with flaccid and spastic dysarthria but not with ataxic dysarthria.⁠¹⁷

Breathing-muscle training is different: expiratory muscle strength training remains one of the restorative options ASHA lists.⁠¹ And practicing speech itself, frequently and intensively, is what the principles of motor learning support.⁠¹

What happens in dysarthria therapy, session by session?

On Medicare, a course of outpatient therapy runs like this:

How often and for how long are sessions?

No trial has tested the best timing, length or intensity of therapy after a stroke or brain injury, and dosage depends on the type and severity of the disease, energy, motivation and support.⁠^1,3 Named programs set their own:

• LSVT LOUD: 16 sessions over 4 weeks.⁠^4,23
• SPEAK OUT!: 12 individual 40-minute sessions, three a week for 4 weeks, then group sessions.⁠²⁸
• Remote personalized therapy (the Dutch PERSPECTIVE trial): 30 minutes, 3 to 4 times a week, for up to 8 weeks, with daily home exercises.⁠²⁹
• Communication therapy after a stroke (ACT NoW): up to three contacts a week for up to 16 weeks, an average of 22 contacts over 13 weeks.⁠²¹

Individual sessions suit learning new techniques, and group sessions give practice in a more natural setting. Starting early may help motor learning, but communication strategies can make speech easier to understand at any point.⁠¹

Can AAC help with dysarthria?

Augmentative and alternative communication (AAC) adds to speech or replaces it, from gestures and signs to communication boards and speech-generating devices.⁠^1,34 It does not mean giving up on speech: AAC use may help natural speech when it is used alongside it, and there are no prerequisites for starting.⁠³⁴

What is speech supplementation?

The simplest AAC adds cues to speech: pointing to the first letter of each word on an alphabet board, pointing to the topic on a display, or adding a gesture.⁠¹ A scoping review found that these strategies consistently improved intelligibility and slowed speech rate.⁠³⁵

Which devices, apps and amplifiers can help?

Options include flip cards, apps, phones or computers to type messages, voice amplifiers, and speech-generating devices, which can be operated with head, foot or eye movement when the arms are weak; a paper board stays as the backup to any high-tech device.⁠^1,13,18 In a progressive disease such as ALS, AAC and voice banking start as early as possible after diagnosis, so the person’s own voice can be used in a device later.⁠^1,18

Medicare covers speech-generating devices as durable medical equipment for people with a severe speech impairment, but not ordinary computers or tablets.⁠¹¹

How does dysarthria affect swallowing, safety and work?

Dysarthria often comes with swallowing problems (dysphagia). After a first stroke, 28% of 221 patients in one study had both, and among adults with neuromuscular disease, swallowing problems affected 36% to 58% in two cohorts.⁠^1,12,36 The SLP checks swallowing as part of the evaluation and teaches safe chewing and swallowing techniques when they are needed; coughing or choking at meals, fever, chills or shortness of breath are reasons to call a provider.⁠^1,13

What helps at work and at home?

The Job Accommodation Network lists voice amplification, including on the telephone, a flexible schedule and job restructuring for weak speech, and AAC devices with telephone access when speech is hard to understand.⁠³⁷ An SLP can also help with phone calls, emergency alerting for times you are home alone, and ways to signal for help within the home.⁠¹⁸ MedlinePlus advises avoiding conversations when you are tired or eating.⁠¹³

How can you understand someone with dysarthria?

Listeners make a large difference. ASHA, its consumer affiliate and MedlinePlus advise:

• Talk in a quiet, well-lit place: turn off the TV, radio and fans, and sit face to face and close together.⁠^1,2
• Watch the speaker’s face and gestures, and wear your own hearing aids and glasses.⁠^1,2
• Listen carefully, be patient and let the person finish.⁠¹³
• If you do not understand, say so; do not pretend. Repeat back the part you did understand, so the speaker does not have to start over, and ask specific questions.⁠^1,2,18
• Give feedback and encouragement for the effort.⁠^1,13

What can the speaker do?

• Get the listener’s attention and name the topic before you start, and say when you change topic.⁠^1,18
• Tell new listeners you have trouble with speech.⁠²
• Start with a keyword, and work on one change at a time.⁠²
• Rest when you can: speech is harder to understand when you are tired.⁠²

Does Medicare cover speech therapy for dysarthria?

Yes. Medicare Part B covers medically necessary outpatient speech therapy, including therapy to maintain function or slow decline; you pay 20% of the Medicare-approved amount after the deductible, and a doctor, nurse practitioner, clinical nurse specialist or physician assistant certifies the need.⁠⁹ Medicare covers it in each setting:

Medicare has no cap on outpatient therapy, but once physical therapy and speech-language pathology together pass $2,480 in a year (the 2026 amount), each claim must confirm that the therapy is medically necessary, and claims past $3,000 can be picked for review.⁠⁴²

Improvement is not required. Medicare covers skilled therapy to maintain function or to prevent or slow decline, not only to restore it, provided the other coverage rules are met; coverage turns on the need for skilled care, not on the potential to improve.⁠¹⁰ That matters in Parkinson’s disease, MS and ALS, where the aim is to keep communication working at each stage.⁠¹ Speech-generating devices are covered separately, as durable medical equipment.⁠¹¹

Medicaid, Marketplace plans and the VA. For adults, speech, hearing and language services are an optional Medicaid benefit, so coverage depends on your state; home health is a mandatory benefit.⁠⁴³ Every Marketplace plan covers rehabilitative and habilitative services and devices, though the specific services vary with each state’s requirements.⁠⁴⁴ For veterans, audiology and speech pathology are standard medical benefits for every enrolled veteran.⁠⁴⁵ With any private plan, ask about visit limits, whether a referral is needed, and whether the SLP is in network.

Is dysarthria permanent?

It depends on the cause: dysarthria may improve, stay the same, or get worse slowly or quickly.⁠¹³

• Stroke or brain injury: it will not get worse and may improve; in one stroke unit, half of those with dysarthria on admission recovered completely within a week.⁠^6,13
• Surgery to the tongue or voice box: it should not get worse and may improve with therapy.⁠¹³
• Medicines or poorly fitting dentures: it can be reversed.⁠¹³
• Progressive disease: people with ALS eventually lose the ability to speak, and some people with Parkinson’s disease or MS do; the goal of therapy is to maximize communication at each stage, not to reverse the decline.⁠^1,13

Communication strategies can make speech easier to understand at any point, even when the speech itself does not change.⁠¹

Dysarthria vs aphasia vs apraxia of speech: what is the difference?

Three conditions are often confused, and they can occur together. ASHA’s comparison:⁠¹

Some people have both dysarthria and apraxia of speech, which makes each harder to diagnose, and dysarthria can occur with language, thinking and swallowing disorders.⁠^1,46

Related conditions: dysphagia; voice disorders, since a breathy, harsh or strained voice, or trouble changing loudness and pitch, can be a sign of damage to the nerves of the voice;⁠¹ cognitive-communication disorders after a brain injury; and the conditions that cause it, among them ALS and Parkinson’s disease.

What are the common myths about slurred speech?

• Myth: slurred speech means someone has been drinking. Intoxication is one cause among many; stroke, Parkinson’s disease, MS, ALS, medicines and even poorly fitting dentures are others.⁠^1,13
• Myth: slurred speech means slow thinking. Dysarthria affects only speech production; it causes no difficulty thinking, remembering or finding words.⁠^1,3
• Myth: tongue and lip strengthening exercises will fix slurred speech. Those exercises have not been shown to improve speech.⁠^7,8
• Myth: therapy cannot help when the disease is progressive. In Parkinson’s, LSVT LOUD beat no therapy with benefits lasting a year, and Medicare pays for therapy that maintains function.⁠^4,10
• Myth: a communication device means giving up on speech. AAC may help natural speech when it is used alongside it.⁠³⁴

How do you find a speech therapist for dysarthria near you?

Look for a licensed speech-language pathologist who sees adults with neurological conditions; for Parkinson’s, ask whether the therapist is trained in LSVT LOUD, since only trained therapists delivered it in the PD COMM trial.⁠⁴

The DrSensory speech therapy directory lists practices by state and city. On a city page, set Care for to Adults and Specialty to Neuro (stroke, TBI, Parkinson’s). A specialty tag comes from the practice’s own description of its services, not from a credential, so ask about their experience with dysarthria and with your condition when you call.

Every SLP needs a state license. ASHA’s Certificate of Clinical Competence (CCC-SLP) is a national credential whose holders have met standards that typically go beyond state licensure, and anyone can check an SLP’s certification on ASHA’s site.⁠^47,48

What should you ask before you book?

• How many adults with dysarthria, and with my condition, have you treated?
• Do you offer LSVT LOUD, or another program with a set number of sessions?
• Will you assess my swallowing as well?
• Can my partner join sessions to learn the listener strategies?
• Do you offer telehealth or home visits, and do you take Medicare or my plan?

Telehealth may be appropriate for some people with dysarthria; ASHA’s standard is that it be of equal quality to in-person care, and you keep the right to ask for in-person sessions.⁠^1,49 If leaving home is hard, Medicare home health covers speech therapy at home for people who are homebound.⁠³⁹ Online speech therapy and in-home therapy explain both.

Sources

1. American Speech-Language-Hearing Association. Dysarthria in adults (Practice Portal). Dysarthria is “a group of neurogenic speech disorders characterized by” “abnormalities in the strength, speed, range, steadiness, tone, or accuracy of movements required for breathing, phonatory, resonatory, articulatory, or prosodic aspects of speech production”; “Dysarthria can adversely affect intelligibility of speech and/or naturalness of speech”; “Dysarthria can result from congenital conditions, or it can be acquired at any age as the result of a neurologic injury, disease, or disorder”; “The severity of the disorder does not necessarily determine the degree of disability”; it “may also co-occur with other neurogenic language, cognitive, and swallowing disorders”; “Aphasia affects language comprehension and expression; dysarthria affects only speech production.” Prevalence: “78%–93% of people with Huntington’s disease have dysarthria”; “Between 40% and 51% of individuals with multiple sclerosis are diagnosed with dysarthria at some point during the course of their disease”; “Approximately 26%–62% of individuals with neuromuscular disease experience dysarthria during the course of their disease”; “dysarthria affects approximately 44%–88% of individuals with Parkinson’s disease”; “22%–58% of individuals with acute stroke present with dysarthria”; “Approximately 30%–86% of individuals with acute to subacute traumatic brain injury experience dysarthria”. Causes include “stroke (hemorrhagic or nonhemorrhagic)”; “traumatic brain injury, chronic traumatic encephalopathy”; “amyotrophic lateral sclerosis, Parkinson’s disease, progressive supranuclear palsy, cerebellar degeneration, corticobasal degeneration, multiple system atrophy, Friedreich’s ataxia, Huntington’s disease”; “multiple sclerosis, encephalitis, Guillain-Barré and associated autoimmune syndromes”; “Neuromuscular disease (e.g., myasthenia gravis, amyotrophic lateral sclerosis, muscular dystrophy)”; “cerebral palsy, Chiari malformation, congenital suprabulbar palsy”; “central and peripheral nervous system tumors; cerebral, cerebellar, or brainstem tumors”; “neurosurgical/postoperative trauma”; “COVID-19, acquired immune deficiency syndrome (AIDS), Creutzfeldt-Jakob disease”; “botulism, carbon monoxide poisoning”; heavy metal toxicity and “lithium toxicity”. Types by site of damage: flaccid, “associated with disorders affecting the lower motor neuron pathways and motor units”; spastic, “associated with bilateral disorders of the upper motor neuron system”; ataxic, “associated with disorders of the cerebellar control circuit”; hypokinetic and hyperkinetic, “associated with disorders of the basal ganglia control circuit”; unilateral upper motor neuron, “associated with unilateral disorders of the upper motor neuron system”; mixed, “various combinations of dysarthria types”; “it may be difficult to determine dysarthria type”. Assessment: SLPs “play a central role in the screening, assessment, diagnosis, and treatment of persons with dysarthria”; the history covers “medications and potential side effects/symptoms” and “variation in effort for speaking in different contexts (e.g., when fatigued, at different times of day, relative to medication schedule)”; “completion of a cranial nerve exam to assess facial, oral, velopharyngeal, and laryngeal function and symmetry”; “assessment of sustained vowel prolongation” and of syllable rates “to judge speed and regularity of jaw, lip, and tongue movement”; “2 to 4 minutes of reading or speaking aloud to assess deterioration over time”; “Intelligibility and comprehensibility are typically reported as a percentage of words correctly identified by a listener”, or as “the number of intelligible or comprehensible words per minute”; the SLP will “assess receptive and expressive language skills in oral and written modalities to help distinguish between dysarthria and aphasia” and assess swallowing; referral to “a neurologist for diagnosis of an underlying etiology” and “a prosthodontist for palatal lift candidacy”; “Muscle weakness or spasticity is present in several dysarthria types; AOS does not present with muscle weakness or spasticity unless there is a concomitant dysarthria”; “dysarthric speech may present with more consistent error patterns”; its differential diagnosis table marks muscle weakness and consistent error patterns as features of dysarthria and not of apraxia of speech or aphasia, articulatory and prosodic deficits as features of dysarthria and apraxia of speech, groping for articulatory postures as a feature of apraxia of speech only, and language processing deficits as a feature of aphasia only. Treatment: “Not all individuals with dysarthria are candidates for treatment”; “Restorative interventions maximize intelligibility by addressing the function of the speech production subsystems”; “Compensatory interventions maximize a person’s participation in activities by addressing functional communication”, by “increasing the speaker’s use of communication strategies”, “improving listener skills and capacity” and “altering the communication environment”; “Sometimes the goal of treatment is to preserve or maintain function or to slow further decline, such as when an individual has a progressive disease”. Techniques include “Postural adjustments (e.g., sitting upright to improve breath support for speech)”, “optimal phrase length based on respiratory support and syntactic boundaries”, “Expiratory muscle strength training using a pressure threshold device”, LSVT LOUD (“an intensive program that targets high phonatory effort to improve loudness”), Pitch Limiting Voice Treatment (“a program for increasing vocal loudness without increasing pitch”), SPEAK OUT! (which “combines individual therapy with weekly speech and singing groups, daily home practice, and education for patients and their care partners”), “pacing strategies, including hand tapping or use of a pacing board or metronome”, “delayed auditory feedback”, “Exaggerated articulation (overarticulation) to emphasize phonetic placement and increase precision” and “palatal lift prosthesis and nasal obturator to occlude nasal airflow”; by referral, “pharyngeal augmentation, pharyngeal flap, or palatal flap to treat velopharyngeal incompetency and improve resonance” and “pharmacological management to relieve symptoms of the underlying neurologic condition”. AAC: “AAC involves supplementing or replacing natural speech and/or writing”; “Speech supplementation, a form of AAC, uses additional cues to enhance the speaker’s spoken message”, as when “The speaker indicates the first letter of a word on a letter board”, “The speaker indicates the topic of the spoken message using a communication display” or “The speaker uses an easily understood gesture with the spoken word or phrase”; “Other augmentative supports include voice amplifiers, artificial phonation devices (e.g., electrolarynx devices and intraoral devices), and oral prosthetics”; in neurodegenerative disease, “initiating AAC systems and voice banking as early as possible following a diagnosis”, and “The goal of treatment is to maximize communication at each stage of the disease, not to reverse decline”. Dose and format: people “may benefit from frequent and intense practice consistent with the principles of motor learning to enhance retention of speech skills”; “blocked, constant practice is associated with skill acquisition, whereas random, variable practice is associated with retention and transfer”; “Dosage may vary depending on the individual’s type and severity of disease, energy level, motivation, and degree of community support”; “care partners and other communication partners can be trained by the SLP to provide opportunities for practice, encourage the use of strategies such as AAC, and give feedback about performance in functional settings”; “Individual treatment may be most appropriate for learning new techniques and strategies. Group treatment provides opportunities to practice techniques and strategies in a naturalistic setting”; “Early initiation of treatment may be beneficial for learning or relearning motor patterns; however, improvements in comprehensibility using communication strategies are possible at any point”; “Telepractice may be appropriate for some individuals with dysarthria”. Partner strategies include “preparing the communication partner by gaining their attention and introducing the topic of conversation before speaking”, “asking for clarification by asking specific questions”, “providing feedback and encouragement”, “optimizing the ability to hear the speaker and to see their visual communication cues (e.g., by wearing prescribed hearing aids and glasses during conversations)”, “reducing background noise (e.g., choose a quiet setting for conversations; turn off TV, radio, and fans)”, “reducing the distance between the speaker and their communication partner” and “using face-to-face seating for conversations”. “Atypical vocal quality (e.g., breathy, harsh, strained) and difficulty changing loudness and pitch can indicate neuromotor damage to the phonatory system.” Checked October 7, 2026.
2. Communication Health Support Association (the consumer affiliate of the American Speech-Language-Hearing Association). Dysarthria. “Dysarthria is a speech disorder that happens when brain or nerve damage changes the way your muscles work. This can make your speech sound slow, slurred, or hard to understand.” Signs include “You slur or mumble when you talk”, “You talk too slowly or too fast”, “You talk too quietly or too loudly”, “You have difficulty moving your tongue, lips, and jaw”, and speech that sounds robotic or choppy. “See a doctor right away if you notice any new difficulty talking. Call 911 if you notice any sudden changes in speech or communication.” Speakers: “Let people know you have trouble with speech before starting a conversation”; “Start with a keyword to give the listener a heads-up.” “Pick one change to focus on.” “Talking can be tiring, and your speech may be harder to understand when you’re tired.” Listeners: “Choose a quiet, well-lit space.” “If you don’t understand, say so. Don’t pretend to understand when you don’t.” “If you don’t understand the whole message, then repeat the part that you understood.” “Watch their face and gestures.” Checked October 7, 2026.
3. Mitchell C, Bowen A, Tyson S, Butterfint Z, Conroy P. Interventions for dysarthria due to stroke and other adult-acquired, non-progressive brain injury. Cochrane Database of Systematic Reviews. 2017;(1):CD002088. doi:10.1002/14651858.CD002088.pub3 (PMID 28121021). “We included five small trials that randomised a total of 234 participants”; the primary analysis “found no evidence in favour of dysarthria intervention compared with any control” (3 trials, 116 participants, low-quality evidence); “A positive finding was short-term improvement in muscle movement, such as tongue and lip control. However, this result is not reliable”. “We found no definitive, adequately powered RCTs of interventions for people with dysarthria.” “Research evidence is not yet sufficiently robust to guide clinical practice.” “People with dysarthria after stroke or brain injury should continue to receive rehabilitation according to clinical guidelines.” “We found no studies that examined timing, duration, or intensity of treatment.” Plain-language summary: “People with dysarthria do not have difficulties thinking, remembering, or retrieving words.”
4. Sackley CM, Rick C, Brady MC, Woolley R, Burton C, Patel S, et al. Lee Silverman voice treatment versus NHS speech and language therapy versus control for dysarthria in people with Parkinson’s disease (PD COMM): pragmatic, UK based, multicentre, three arm, parallel group, unblinded, randomised controlled trial. BMJ. 2024;386:e078341. doi:10.1136/bmj-2023-078341 (PMID 38986549). “388 people with Parkinson’s disease and dysarthria”: “130 to Lee Silverman voice treatment (LSVT LOUD), 129 to NHS speech and language therapy, and 129 to no speech and language therapy.” “LSVT LOUD consisted of four, face-to-face or remote, 50 min sessions each week delivered over four weeks. Home based practice activities were set for up to 5-10 mins daily on treatment days and 15 mins twice daily on non-treatment days”; “Only speech and language therapists or therapist assistants trained in LSVT LOUD could deliver the intervention.” At three months, LSVT LOUD users “reported lower voice handicap index scores” than those with no therapy “(−8.0 points (99% confidence interval −13.3 to −2.6); P<0.001)”, and “Patients in the LSVT LOUD group also reported lower voice handicap index scores than did those randomised to NHS speech and language therapy”; “No evidence suggests a difference in voice handicap index scores between NHS speech and language therapy and no speech and language therapy”. “A robust signal shows that, after three months, LSVT LOUD is effective compared with no SLT for the reduction of dysarthria related to Parkinson’s disease, which persists throughout the 12 months from starting treatment.” NHS therapy was given at lower intensity (“404 mins (234); five sessions” against a median of 16 LSVT LOUD sessions): “NHS therapy was delivered at a much lower intensity and did not show benefit over control. Therefore, these results should not be interpreted as evidence of no beneficial effect for all NHS SLT theoretical approaches, across all dosages.” “93 adverse events (predominately vocal strain) were reported in the LSVT LOUD group, 46 in the NHS speech and language therapy group”; “No serious adverse events were recorded”; “The higher rate of vocal strain with LSVT LOUD treatment was mostly a minor, transient issue at an acceptable rate in relation to the level of benefit”. “Dysarthric symptoms vary in their response to increased dopaminergic medication and can become worse with subthalamic stimulation surgery”; “re-intervention might still be required should the treatment effect wear off or as their Parkinson’s disease progresses and their dysarthria deteriorates”. Limits: “Differences in access to therapy and intervention format could not be concealed from participants, making trial blinding unfeasible”; “most participants were in the early stages of Parkinson’s disease with mild speech impairment”; the trial closed early during COVID-19. Funded by the NIHR; “LSVT LOUD training was provided by LSVT Global. The funder and LSVT Global had no role in the PD COMM trial design, data collection, data analysis, data interpretation, or writing of the report.”
5. Centers for Disease Control and Prevention. Signs and symptoms of stroke (May 19, 2026). Signs include “Sudden confusion, trouble speaking, or difficulty understanding speech”; “Call 9-1-1 right away if you or someone else has any of these symptoms”; in the B.E. F.A.S.T. test for speech, “Ask the person to repeat a simple phrase. Is the speech slurred or strange?”; “The stroke treatments that work best are available only if the stroke is recognized and diagnosed within 3 hours of the first symptoms”; “Note the time when any symptoms first appear”; “Do not drive to the hospital or let someone else drive you”; a TIA “is a sign of a serious condition that will not go away without medical help”, so “tell a health care team about the symptoms right away.” Checked October 7, 2026.
6. De Cock E, Oostra K, Bliki L, Volkaerts AS, Hemelsoet D, De Herdt V, et al. Dysarthria following acute ischemic stroke: prospective evaluation of characteristics, type and severity. International Journal of Language & Communication Disorders. 2021;56(3):549–557. doi:10.1111/1460-6984.12607 (PMID 33580596). First-ever ischemic stroke, Ghent University Hospital: “A total of 67 out of 151 participants (44%; mean age = 69 years; SD = 13; 28 females) were diagnosed with dysarthria in the acute phase following stroke.” “Unilateral upper motor neuron (UUMN) was the main dysarthria type present in 52% (25/48) of participants.” “UUMN was the dominant dysarthria type, and the majority of participants had a mild dysarthria.” On the NIHSS speech item at admission, “46% (70/151) of participants had dysarthria, of which half recovered completely from their dysarthria within 1 week after stroke symptom onset.”
7. McCauley RJ, Strand E, Lof GL, Schooling T, Frymark T. Evidence-based systematic review: effects of nonspeech oral motor exercises on speech. American Journal of Speech-Language Pathology. 2009;18(4):343–360. doi:10.1044/1058-0360(2009/09-0006) (PMID 19638484). “Fifteen studies met inclusion criteria”; “The critical appraisals identified significant weaknesses in almost all studies.” “Insufficient evidence to support or refute the use of OMEs to produce effects on speech was found in the research literature.”
8. Mackenzie C, Muir M, Allen C, Jensen A. Non-speech oro-motor exercises in post-stroke dysarthria intervention: a randomized feasibility trial. International Journal of Language & Communication Disorders. 2014;49(5):602–617. doi:10.1111/1460-6984.12096 (PMID 24889103). “Thirty-nine participants were randomized”; therapy was “delivered in eight home-based SLT sessions”, with non-speech oro-motor exercises added in one group. “The inclusion of NSOMExs, delivered in accordance with standard clinical practice, did not appear to influence outcomes.” A small feasibility trial.
9. Centers for Medicare & Medicaid Services. Speech-language pathology services (Medicare.gov). Part B covers “medically necessary outpatient speech-language pathology services”, which “provide evaluation and treatment to regain and strengthen speech and language skills. This includes cognitive and swallowing skills, or therapy to improve or maintain current function or slow decline”; “Your doctor or other health care provider (including a nurse practitioner, clinical nurse specialist, or physician assistant) must certify you need this care”; after the Part B deductible you pay 20% of the Medicare-approved amount; “There’s no limit on how much Medicare pays for your medically necessary outpatient speech-language pathology services in one calendar year.” Checked October 7, 2026.
10. Centers for Medicare & Medicaid Services. Jimmo settlement. The Jimmo Settlement Agreement (January 2013) “clarified that the Medicare program covers skilled nursing care and skilled therapy services under Medicare’s skilled nursing facility, home health, and outpatient therapy benefits when a beneficiary needs skilled care in order to maintain function or to prevent or slow decline or deterioration (provided all other coverage criteria are met)”; coverage “does not turn on the presence or absence of a beneficiary’s potential for improvement, but rather on the beneficiary’s need for skilled care.” Checked October 7, 2026.
11. Centers for Medicare & Medicaid Services. National coverage determination: speech generating devices (50.1). “Speech generating devices are considered to fall within the durable medical equipment (DME) benefit category”; “They are covered for patients who suffer from a severe speech impairment and have a medical condition that warrants the use of a device”; covered forms include “software that allows a computer or other electronic device to generate audible/verbal speech”; “Computers and tablets are generally not considered DME because they are useful in the absence of an illness or injury”; “Internet or phone services or any modification to a patient’s home to allow use of the speech generating device are not covered by Medicare.” Checked October 7, 2026.
12. Flowers HL, Silver FL, Fang J, Rochon E, Martino R. The incidence, co-occurrence, and predictors of dysphagia, dysarthria, and aphasia after first-ever acute ischemic stroke. Journal of Communication Disorders. 2013;46(3):238–248. doi:10.1016/j.jcomdis.2013.04.001 (PMID 23642855). Chart review of 221 patients: “Estimates of the incidence of dysphagia, dysarthria, and aphasia were 44% (95% CI, 38-51), 42% (95% CI, 35-48) and 30% (95% CI, 25-37), respectively.” “The highest co-occurrence of any two impairments was 28% (95% CI, 23-34) for the presence of both dysphagia and dysarthria.”
13. MedlinePlus, National Library of Medicine. Dysarthria (Medical Encyclopedia; reviewed August 19, 2024). Alternative names: “Impairment of speech; Slurred speech; Speech disorders - dysarthria”. “Depending on its cause, dysarthria may develop slowly or occur suddenly.” “Their speech is poorly pronounced (such as slurring), and the rhythm or speed of their speech changes”; signs include “Speaking softly or in a whisper” and “Speaking in a nasal or stuffy, hoarse, strained, or breathy voice”; “A person with dysarthria may also drool and have problems chewing or swallowing.” Causes also include “Surgery for head and neck cancer, such as partial or total removal of the tongue or voice box”, “Alcohol or illegal drug or medicine intoxication”, “Poorly fitting dentures” and “Side effects of medicines that act on the central nervous system, such as narcotics, phenytoin, or carbamazepine”. If the cause is unknown, tests can include “Imaging tests, such as an MRI or CT scan of the brain or neck”, “Nerve conduction studies and electromyogram to check the electrical function of the nerves or muscles” and “Blood tests for toxins or vitamin levels”; “A procedure called laryngoscopy may be done.” Treatment can include “Safe chewing or swallowing techniques, if needed”; aids include “Apps that use photos or speech”, “Computers or cell phones to type out words” and “Flip cards with words or symbols”; advice includes “To avoid conversations when you are tired or eating”; for listeners, “Listen carefully and allow the person to finish. Be patient.” and “Give positive feedback for their effort.” Outlook: “Depending on the cause of dysarthria, symptoms may improve, stay the same, or get worse slowly or quickly.” “People with ALS eventually lose the ability to speak.” “Some people with Parkinson disease or multiple sclerosis lose the ability to speak.” “Dysarthria caused by medicines or poorly fitting dentures can be reversed.” “Dysarthria caused by a stroke or brain injury will not get worse, and may improve.” “Dysarthria after surgery to the tongue or voice box should not get worse, and may improve with therapy.” Contact a provider for “Chest pain, chills, fever, shortness of breath, or other symptoms of pneumonia” or “Coughing or choking”. Checked October 7, 2026.
14. Vogel AP, Folker J, Poole ML. Treatment for speech disorder in Friedreich ataxia and other hereditary ataxia syndromes. Cochrane Database of Systematic Reviews. 2014;(10):CD008953. doi:10.1002/14651858.CD008953.pub2 (PMID 25348587). “The type of speech impairment most commonly reported in hereditary ataxias is dysarthria.” “Fourteen clinical trials, involving 721 participants, met the criteria”, 13 of them drug trials; “No studies utilised traditional speech therapies.” “There is insufficient and low or very low quality evidence from either RCTs or observational studies to determine the effectiveness of any treatment for speech disorder in any of the hereditary ataxia syndromes.”
15. National Institute of Neurological Disorders and Stroke. Myasthenia Gravis (last reviewed March 13, 2026). “Myasthenia gravis is a chronic neuromuscular disease that causes weakness in the voluntary muscles.” Symptoms include “Impaired speech (dysarthria)” and “Difficulty swallowing”. Checked October 7, 2026.
16. American Speech-Language-Hearing Association. Distinguishing perceptual characteristics and physiologic findings by dysarthria type (Practice Portal; table adapted from Duffy 2020). Flaccid: “hypernasality continuous breathiness diplophonia audible inspiration or stridor nasal emission short phrases”, with “rapid deterioration of speech quality and performance, with notable recovery with rest” and “rapid weakening of muscles with use and recovery with rest”; spastic: “slow rate strained or harsh voice quality pitch breaks”; ataxic: “excess and equal stress irregular articulatory breakdowns distorted vowels”, “excessive loudness variation telescoping or slurring of syllables”; hypokinetic: “monopitch monoloudness loudness decay”, “loudness decay, and reduced stress and loudness”, “normal speech rate or tendency for rapid or accelerated speech rate”, “inappropriate silences”; hyperkinetic: “voice stoppages/arrests voice tremor”, “marked deterioration with increased rate”, “intermittent breathy or aphonic segments”; unilateral upper motor neuron: “slow rate imprecise articulation irregular articulatory breakdowns strained voice quality reduced loudness”, with “unilateral lower-face weakness”. Checked October 7, 2026.
17. Clark HM, Duffy JR, Strand EA, Hanley H, Solomon NP. Orofacial muscle strength across the dysarthrias. Brain Sciences. 2022;12(3):365. doi:10.3390/brainsci12030365 (PMID 35326321). Mayo Clinic study of 79 speakers with dysarthria: “Flaccid (bulbar) and spastic (pseudobulbar) dysarthrias share the feature of neuromuscular weakness”, while weakness “is not apparent in hypokinetic (parkinsonian), ataxic (cerebellar), or hyperkinetic (dystonia, chorea) dysarthrias”; “speakers with PD…would be predicted to exhibit hypokinetic dysarthria”; “the predicted dysarthria type associated with ALS would be expected to be mixed spastic–flaccid.” “The results generally support predictions that orofacial weakness accompanies flaccid and/or spastic dysarthria but not ataxic dysarthria.”
18. The ALS Association. FYI: Suggestions and information about speech changes & augmentative alternative communication (AAC) (fact sheet, June 10, 2020). “This causes dysarthria – the term used to describe slow, effortful, slurred speech, and breathy or hoarse voice.” “Speaking may make you tired, especially later in the day.” “Therapeutic oral exercises designed to strengthen muscles for people with other forms of dysarthria have not been demonstrated to improve speech for people with ALS”; “Oral motor exercises are not recommended for speech changes resulting from ALS”. Advice includes to “begin Message and Voice Banking so that your own voice can be used in a speech generating device (SGD) or text-to-speech (TTS) app if ever required”; to teach partners “to repeat back any part of a sentence that they DID understand”; “Alert your partner if you are shifting topics and name the new topic.” “a removable, palatal lift appliance” for a nasal quality; “For those with very weak or no arm movement, alternative access equipment can enable a person to operate an SGD or tablet with head, foot or eye movement.” “Low-tech communication systems, like paper communication boards, are an essential backup to your high-tech speech generating device.” “A speech therapist will have other strategies to help with challenges like phone communication, emergency alerting systems for times when you are home alone, and tools for signaling to others within the home if you have a need.” Checked October 7, 2026.
19. National Institute of Neurological Disorders and Stroke. Signs and Symptoms (Stroke; last reviewed July 23, 2026). “S - Speech: Ask the person to repeat a simple phrase. Is the speech slurred or strange?” “If you see any of these three signs, call 9-1-1 right away.” “The best stroke treatments can only be used within four and a half hours of the first symptoms.” “If stroke symptoms go away after a few minutes, it may be a transient ischemic attack (TIA)”; “Although brief, a TIA is a sign of a serious condition that will not go away without medical help.” Checked October 7, 2026.
20. American Stroke Association (American Heart Association). Stroke symptoms and warning signs. B.E. F.A.S.T.: “Is speech slurred or difficult to understand? Ask the person to repeat a simple sentence.” “If you have any of these symptoms or see someone else having them, call 911 immediately!” “Posterior circulations strokes (a stroke that occurs in the back part of the brain)” have symptoms that include “Vertigo, sensation like the room is spinning”, “Imbalance or one-sided arm or leg weakness”, “Slurred speech or difficulty in speech (dysarthria)”, “Double vision or other vision problems”, a headache, and “Nausea and/or vomiting”. For a TIA: “Call 911 even if the symptoms go away.” Checked October 7, 2026.
21. Bowen A, Hesketh A, Patchick E, Young A, Davies L, Vail A, et al. Effectiveness of enhanced communication therapy in the first four months after stroke for aphasia and dysarthria: a randomised controlled trial. BMJ. 2012;345:e4407. doi:10.1136/bmj.e4407 (PMID 22797843). ACT NoW: “170 adults (mean age 70 years) randomised within two weeks of admission to hospital with stroke”; therapy could be “up to three contacts per week for up to 16 weeks”, and averaged “22 contacts (18 hours) over 13 weeks”. The comparison was “similarly resourced social contact (without communication therapy) from employed visitors”. “The estimated six months group difference was not statistically significant, with 0.25 (95% CI –0.19 to 0.69) points in favour of therapy.” “Communication therapy had no added benefit beyond that from everyday communication in the first four months after stroke.”
22. Kim Y, Kim M, Kim S, Kim J, Shin JH, Chang Y, et al. Efficacy of digital speech therapy for poststroke dysarthria: randomized noninferiority trial. Journal of Medical Internet Research. 2026;28:e81938. doi:10.2196/81938 (PMID 42149971). “A total of 73 participants were enrolled”, each assigned a smartphone app or a printed workbook: “60 minutes of therapy per day, 5 days per week, for 4 weeks”. “Digital speech therapy was noninferior to conventional workbook-based therapy in improving speech intelligibility”; app adherence was “64.6% based on app logs”. Limits: participants were cognitively intact, without aphasia and able to use a smartphone. “YK, MK, and SK are employees of Haii Corp, the developer of the smartphone-based speech therapy app evaluated in this study”.
23. Ramig L, Halpern A, Spielman J, Fox C, Freeman K. Speech treatment in Parkinson’s disease: randomized controlled trial (RCT). Movement Disorders. 2018;33(11):1777–1791. doi:10.1002/mds.27460 (PMID 30264896). “As many as 89% of people with Parkinson’s disease (PD) develop speech disorders”; “Reductions in vocal loudness are among the first and most pervasive changes in speech”, and “speech disorders in PD are generally unresponsive to pharmacological or neurosurgical interventions alone”. 64 people with Parkinson’s were randomized to LSVT LOUD, LSVT ARTIC (articulation) or no treatment. Dose: “Individual treatment session of 1 hour, 4 consecutive days per week over a 4-week period”; daily exercises include holding a vowel “in a good-quality, loud voice, for as long as possible” and “Participant reads 10 self-generated phrases he/she says daily in functional living”; “Tasks increase in length of utterance and difficulty across weeks, progressing from words to phrases to sentences to reading to conversation”; homework “10 minutes, performed once per day” on treatment days and “15 minutes, performed twice per day” on other days, plus a carryover assignment: “Participant is to use the louder voice practiced in exercises in a real-world communication situation”. “At 1 and 7 months, SPL between-group comparisons showed greater improvements for LSVT LOUD (n = 22) than LSVT ARTIC (n = 20; P < 0.05) and UNTXPD (n = 22; P < 0.05)”; “Only LSVT LOUD maintained CETI-M improvements at 7 months.” Funded by “National Institutes of Health-National Institute of Deafness and Other Communication Disorders (NIH-NIDCD) R01 DC01150 and LSVT Global, Inc.”; after the study, “Ramig, Halpern, and Fox have had employment roles with LSVT Global, and Spielman and Freeman have been paid consultants.”
24. Levy ES, Moya-Galé G, Chang YHM, Freeman K, Forrest K, Brin MF, et al. The effects of intensive speech treatment on intelligibility in Parkinson’s disease: a randomised controlled trial. eClinicalMedicine. 2020;24:100429. doi:10.1016/j.eclinm.2020.100429 (PMID 32639484). The same trial’s intelligibility outcome: blinded listeners transcribed speech of 57 patients after “intensive speech treatment (16 1-hour sessions/1 month)”. Transcription accuracy rose more with the voice treatment than with no treatment (“d = 42·8%, 95% CI 22·4 - 63·2”); “Differences between TA changes in the treatment targeting articulation and in the no treatment group were not significant”. “Manuscript preparation and intelligibility assessment were funded in part by LSVT Global, Inc.”; the senior author “is employed as Chief Scientific Officer and has ownership interest in the for-profit company LSVT Global, Inc.”
25. Ramig LO, Sapir S, Countryman S, Pawlas AA, O’Brien C, Hoehn M, et al. Intensive voice treatment (LSVT) for patients with Parkinson’s disease: a 2 year follow up. Journal of Neurology, Neurosurgery, and Psychiatry. 2001;71(4):493–498. doi:10.1136/jnnp.71.4.493 (PMID 11561033). “Thirty three patients with idiopathic Parkinson’s disease were stratified and randomly assigned to two treatment groups”; “The LSVT was significantly more effective than the RET in improving (increasing) SPL and STSD immediately post-treatment and maintaining those improvements at 2 year follow up.”
26. Herd CP, Tomlinson CL, Deane KH, Brady MC, Smith CH, Sackley CM, et al. Speech and language therapy versus placebo or no intervention for speech problems in Parkinson’s disease. Cochrane Database of Systematic Reviews. 2012;(8):CD002812. doi:10.1002/14651858.CD002812.pub2 (PMID 22895930). “Three randomised controlled trials with a total of 63 participants”; “Vocal loudness for reading a passage increased by 6.3 dB (P = 0.0007) in one trial, and 11.0 dB (P = 0.0002) in another trial.” Because of small numbers and methodological flaws, “there is insufficient evidence to conclusively support or refute the efficacy of SLT for speech problems in Parkinson’s disease.”
27. Herd CP, Tomlinson CL, Deane KH, Brady MC, Smith CH, Sackley CM, et al. Comparison of speech and language therapy techniques for speech problems in Parkinson’s disease. Cochrane Database of Systematic Reviews. 2012;(8):CD002814. doi:10.1002/14651858.CD002814.pub2 (PMID 22895931). “Six trials involving 159 patients satisfied the inclusion criteria.” “LSVT-LOUD also outperformed LSVT-ARTIC and Respiration therapy (RT) in improving loudness”, but “there is insufficient evidence to support or refute the efficacy of any form of SLT over another to treat speech problems in patients with Parkinson’s disease.”
28. Behrman A, Cody J, Elandary S, Flom P, Chitnis S. The effect of SPEAK OUT! and The LOUD Crowd on dysarthria due to Parkinson’s disease. American Journal of Speech-Language Pathology. 2020;29(3):1448–1465. doi:10.1044/2020_AJSLP-19-00024 (PMID 32421347). Not randomized: one treated group compared over time with 25 untreated healthy adults. “Forty individuals with idiopathic PD received SPEAK OUT! in 12 individual 40-min sessions 3 times per week for 4 consecutive weeks and also participated in The LOUD Crowd.” “Posttherapy, mean intensity was greater”, and “Cepstral peak prominence and Voice-Related Quality of Life scores were significantly higher (improved) after therapy.” Disclosures: “Jennifer Cody is a paid employee of Parkinson Voice Project. Samantha Elandary is the CEO of Parkinson Voice Project and a member of its Board of Directors.”
29. Maas JJL, de Vries NM, IntHout J, Bloem BR, Kalf JG. Effectiveness of remotely delivered speech therapy in persons with Parkinson’s disease – a randomised controlled trial. eClinicalMedicine. 2024;76:102823. doi:10.1016/j.eclinm.2024.102823 (PMID 39309726). PERSPECTIVE trial, the Netherlands: “214 patients were enrolled in the intervention group (n = 109) or control group (n = 105)”, “comparing 8 weeks of personalised remote speech therapy to no intervention (waiting list design)”. The intensive form was given “3–4 times per week for 30 min, with a maximum treatment trajectory of 8 weeks. Patients also perform daily home-based exercises.” Overall quality of life did not differ significantly (“p = 0.056”); “Personalised remote speech therapy improved communication-related quality of life, but not overall quality of life.” The communication result came from a post hoc analysis.
30. Theodoros DG, Hill AJ, Russell TG. Clinical and quality of life outcomes of speech treatment for Parkinson’s disease delivered to the home via telerehabilitation: a noninferiority randomized controlled trial. American Journal of Speech-Language Pathology. 2016;25(2):214–232. doi:10.1044/2015_AJSLP-15-0005 (PMID 27145396). “31 participants with dysarthria associated with PD from a metropolitan area were randomly assigned to either face-to-face or online Lee Silverman Voice Treatment (LSVT LOUD)”; “Noninferiority of online treatment was confirmed through comparable clinical and quality of life outcomes for the metropolitan online and face-to-face treatment groups.”
31. Code of Federal Regulations, 42 CFR §410.61, Plan of treatment requirements for outpatient rehabilitation services. “The plan is established before treatment is begun by one of the following”, among them “A speech-language pathologist who furnishes the speech-language pathology services”; “The plan prescribes the type, amount, frequency, and duration of the physical therapy, occupational therapy, or speech-language pathology services to be furnished to the individual, and indicates the diagnosis and anticipated goals.” Text as published in the eCFR. Checked October 7, 2026.
32. Code of Federal Regulations, 42 CFR §424.24(c), Outpatient physical therapy, occupational therapy, and speech-language pathology services. When an SLP establishes the plan, “the certification must be signed by a physician or by a nurse practitioner, clinical nurse specialist, or physician assistant who has knowledge of the case”; “Recertification is required at least every 90 days”; “No references to an order or referral in this subsection shall be construed to require an order or referral for outpatient physical therapy, occupational therapy, or speech-language pathology services.” Text as published in the eCFR. Checked October 7, 2026.
33. Centers for Medicare & Medicaid Services. Medicare Benefit Policy Manual, Chapter 15: Covered medical and other health services (Rev. 13889, issued July 30, 2026), section 220.3. “The progress report provides justification for the medical necessity of treatment”; “The minimum progress report period shall be at least once every 10 treatment days.” Checked October 7, 2026.
34. American Speech-Language-Hearing Association. Augmentative and alternative communication (Practice Portal). Unaided forms “do not require an external tool” (gestures, signs, facial expressions); aided forms “require some form of external tool, either electronic or nonelectronic”; “Examples of acquired disabilities that may benefit from AAC include cerebrovascular accidents (i.e., stroke); traumatic or acquired brain injuries; neurodegenerative diseases, such as ALS, supranuclear palsy, primary progressive aphasia, and apraxia; disability following surgeries (e.g., glossectomy, laryngectomy)”; “There are no prerequisites for AAC intervention”; “AAC use may help improve natural speech when used in a multimodal approach”; “selections can be made via eye gaze, head pointing, or scanning methods”, and direct selection can use a joystick, eye gaze, a head mouse or “brain–computer interface technology”; with voice banking “an individual can record a large inventory of speech, which is then used to create a synthetic voice that approximates their natural voice”, and “Voice banking should be completed when a communicator’s energy and skills are sufficient to generate clear speech”; with message banking “an individual can use their own voice or a proxy voice to digitally record and store messages, which may include words, phrases, sentences, and sounds using natural voice, inflection, and intonation”; “Medicare may not cover AAC devices in all settings (e.g., skilled nursing facilities, hospice).” Checked October 7, 2026.
35. Hanson EK, Beukelman DR, Yorkston KM. Communication support through multimodal supplementation: a scoping review. Augmentative and Alternative Communication. 2013;29(4):310–321. doi:10.3109/07434618.2013.848934 (PMID 24229335). “Speech supplementation strategies improve spoken communication for people with motor speech disorders who experience reduced speech intelligibility.” “studies of traditional supplementation consistently reported positive outcomes, including increased intelligibility, decreased speech rate, and positive attitudes toward speakers.”
36. Knuijt S, Kalf JG, de Swart BJ, Drost G, Hendricks HT, Geurts AC, et al. Dysarthria and dysphagia are highly prevalent among various types of neuromuscular diseases. Disability and Rehabilitation. 2014;36(15):1285–1289. doi:10.3109/09638288.2013.845255 (PMID 24151818). Two Dutch cohorts of adults with neuromuscular disease (102 and 118 patients): “The pooled prevalence of dysarthria was 46% (95% CI: 36.5-55.9) and 62% (95% CI: 53.3-70.8) in the unselected and selected cohorts, respectively.” “The pooled prevalence of dysphagia was 36% (95% CI: 27.1-45.7) and 58% (95% CI: 49.4-67.2)”.
37. Job Accommodation Network (US Department of Labor, Office of Disability Employment Policy). Speech-language impairment. “The ADA does not contain a definitive list of medical conditions that constitute disabilities”; a person with a disability “has a physical or mental impairment that substantially limits one or more” major life activities, has a record of one, or is regarded as having one. Accommodation ideas: for no speech or unintelligible speech, an “Augmentative and Alternative Communication (AAC) Device”, “Communicate Another Way” and “Speech Generating Communication Devices with Telephone Access”, with job restructuring for unintelligible speech; for weak speech, a flexible schedule, job restructuring, voice amplification and “Outgoing Voice Amplification - Telephone”. Checked October 7, 2026.
38. Centers for Medicare & Medicaid Services. Telehealth (Medicare.gov). “Through December 31, 2027, Medicare covers telehealth services that you can get from anywhere in the U.S., including your home”; the examples listed include speech therapy, cognitive assessments and “Caregiver training services”; after the Part B deductible you pay 20% of the Medicare-approved amount, and “For most telehealth services, you’ll pay the same amount that you would if you got the services in person”; Medicare Advantage plans “may offer more telehealth benefits than the basic coverage in Original Medicare.” Checked October 7, 2026.
39. Centers for Medicare & Medicaid Services. Home health services (Medicare.gov). Home health care helps you “maintain your current condition or level of function, or slow your rate of decline”; covered services include “speech-language pathology services (if you meet certain conditions)”; you must need part-time or intermittent skilled services and be homebound: “Leaving your home isn’t recommended because of your condition or you have trouble leaving your home without help” and “You’re normally unable to leave your home and leaving takes a lot of effort”; “You can still get home health care if you attend adult day care”; a provider “must see you in person and confirm you need home health care”; “You pay nothing for covered home health services.” Checked October 7, 2026.
40. Centers for Medicare & Medicaid Services. Skilled nursing facility care (Medicare.gov). Covered services include “Speech-language pathology services (if they’re needed to meet your health goal)”; Medicare covers SNF care only after “a prior medically necessary inpatient hospital stay of at least 3 days in a row”; eligibility includes needing skilled care “to improve or maintain your current condition, or to prevent or delay it from getting worse”; in 2026, “Days 1–20: You pay $0 each day after you pay the $1,736 deductible”; “Part A limits SNF coverage to 100 days in each benefit period.” Checked October 7, 2026.
41. Centers for Medicare & Medicaid Services. Inpatient rehabilitation care (Medicare.gov). Part A covers care in an inpatient rehabilitation facility, including rehabilitation services such as speech-language pathology; “Your health care provider must certify that you have a medical condition requiring intensive rehabilitation, continued medical supervision, and coordinated care from your providers”; in 2026, “Days 1-60: After you pay the $1,736 deductible you pay $0 each day.” Checked October 7, 2026.
42. Centers for Medicare & Medicaid Services. Therapy services. The Bipartisan Budget Act of 2018 repealed the outpatient therapy caps and “preserves the former therapy cap amounts as thresholds above which claims must include the KX modifier as a confirmation that services are medically necessary as justified by appropriate documentation in the medical record”; “For CY 2026 this KX modifier threshold amount is: $2,480 for PT and SLP services combined”; “the MR threshold is $3,000 for PT and SLP services”, and “not all claims exceeding the MR threshold amount are subject to review.” Checked October 7, 2026.
43. Medicaid.gov (Centers for Medicare & Medicaid Services). Mandatory & optional Medicaid benefits. “States are required to provide all mandatory benefits under federal law. States may provide optional benefits if they choose to add them through the state plan process”; mandatory benefits include home health services and nursing facility services; optional benefits include “Speech, hearing and language disorder services.” Checked October 7, 2026.
44. HealthCare.gov (Centers for Medicare & Medicaid Services). What Marketplace health insurance plans cover. “All plans offered in the Marketplace cover these 10 essential health benefits”, among them “Rehabilitative and habilitative services and devices (services and devices to help people with injuries, disabilities, or chronic conditions gain or recover mental and physical skills)”; “Specific services covered in each broad benefit category can vary based on your state’s requirements.” Checked October 7, 2026.
45. Veterans Health Administration. VHA Directive 1170.02(1): VHA audiology and speech pathology services (December 9, 2020; amended July 19, 2022). The directive covers “disorders of hearing, tinnitus, balance, speech, language, voice, fluency, cognitive and swallowing”; “Audiology and speech pathology services are standard medical benefits available to all enrolled Veterans.” Checked October 7, 2026.
46. National Institute on Deafness and Other Communication Disorders. What Is Apraxia of Speech? (last updated October 31, 2017). “AOS is not caused by weakness or paralysis of the speech muscles”; “Weakness or paralysis of the speech muscles results in a separate speech disorder, known as dysarthria”; “Some people have both dysarthria and AOS, which can make diagnosis of the two conditions more difficult.” Checked October 7, 2026.
47. American Speech-Language-Hearing Association. Information about ASHA certification. The CCC is “a nationally recognized professional credential that represents a level of excellence in the field”; holders “have voluntarily met rigorous academic and professional standards, typically going beyond the minimum requirements for state licensure.” Checked October 7, 2026.
48. American Speech-Language-Hearing Association. Audiology and speech-language pathology certification. ASHA’s public tool lets anyone “Verify the status of an individual’s Certificate of Clinical Competence in Audiology (CCC-A) or Speech-Language Pathology (CCC-SLP).” Checked October 7, 2026.
49. American Speech-Language-Hearing Association. Telepractice (Practice Portal). “Use of telepractice should be of equal quality to in-person services”; informed consent includes “the client’s right to request in-person services at any time”; “Clinicians should verify state licensure/certification requirements in the state from which the clinician provides services as well as the state in which the client receives services prior to initiating services.” Checked October 7, 2026.

Medical disclaimer. This page is for general educational purposes and does not constitute medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider about your individual situation.