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Speech therapy for Parkinson's disease

Quieter Speech in Parkinson's Disease: LSVT LOUD Training and Voice Exercises at Home

20 June 2026About 12 min read

Many families of people with Parkinson's disease know this situation. The patient feels that their speech is normal, while the family keeps saying "speak up, we can't hear you". The family's hearing is not the problem, and the patient is not too lazy to speak. It is a nerve mechanism caused by Parkinson's disease. The quieter speech in Parkinson's disease (called hypophonia in medicine) does not come from damage to the throat or vocal cords. It comes from an inaccurate internal calibration in the brain of how loud the person is. Understanding this explains why LSVT LOUD, the voice treatment with the strongest evidence in Parkinson's disease, seems to go against intuition. It does not ask the patient to practise clear articulation. It asks them to practise being loud, deliberately and with effort. This article explains the mechanism of hypophonia, why training for loudness is used, the evidence for and the limits of LSVT LOUD, daily voice exercises at home, and when to see a speech therapist.

About 90%
The proportion of people with Parkinson's disease who develop hypokinetic dysarthria. Quieter speech (hypophonia) is one of the most common and earliest speech features.
Moya-Galé & Levy 2019
Only about 3 to 4%
The proportion of people with Parkinson's disease who actually receive speech therapy. Most patients with speech problems are never referred, which is the biggest gap in treatment today.
Moya-Galé & Levy 2019
12 to 24 months
How long the gain in volume (sound pressure level, SPL) from LSVT LOUD can last. An RCT with 2 years of follow-up found that its effect was better than breathing therapy alone and was maintained.
Ramig et al. 2001

Why does speech get quieter in Parkinson's disease?

The speech problems of Parkinson's disease are known together as hypokinetic dysarthria. They come from degeneration of the nerve and movement pathways that control voicing, which affects the coordination of breathing, vocal cords, tongue and lips. The most common and earliest problem is reduced volume (hypophonia). The muscles used for voicing do not work hard enough, the outflow of air is too weak, and the whole voice becomes quieter. A review of dysarthria in Parkinson's disease (Moya-Galé & Levy 2019) noted that nearly 90% of patients have this kind of problem, and that reduced volume is one of the earliest features.

A quieter voice comes from a problem with nerve signals. It does not come from an "ageing throat" or "not enough breath". The root of the problem is not in the throat, so throat lozenges, clearing the throat or speaking slowly do not help. The patient needs training that targets the effort of voicing.

Inaccurate internal calibration: the patient feels already loud enough

The core of the voice problem in Parkinson's disease, and the most confusing part, is inaccurate internal calibration. The patient feels that they are loud enough, while the measured volume is clearly low. The patient is not unwilling to speak up. The brain's volume meter reads wrongly. The patient believes they are using a normal volume, and others already hear it as quite quiet.

The details of the evidence need to be explained. A study of loudness perception and speech intensity control in Parkinson's disease (Clark et al. 2014) found that the patients' perception of their own and other people's speech intensity had a restricted range and an abnormal pattern, and that they did not simply overestimate their own volume in every case. The accurate description is a biased calibration of perception. It should not be simplified to "the patient must feel they are loud". Clinically, this bias in perception explains the gap between the patient saying "I am loud enough" and the family saying "we can't hear you".

One focus of treatment is for the patient to accept that, for others to hear comfortably, the voice has to feel too loud to the patient.
The recalibration principle of LSVT LOUD (Fox et al. 2012)

Why train for loudness and not for clarity?

When speech is slurred and hard to understand, the natural response is to practise articulating the words clearly. LSVT LOUD does not do this. Its core is a single target: it increases only the effort of the whole voicing system (volume) and does not correct articulation, speaking rate and intonation one by one.

When the overall effort of voicing increases, breathing support, closing of the vocal cords and the size of articulator movements are all pulled up together, so volume, clarity and the rise and fall of intonation improve at the same time. These problems share a common root, which is that voicing movements are too small. There is only one instruction, "be loud". It is simple to remember, so the patient finds it easier to remind themselves and keep applying it in daily life, without having to manage several things at once (Fox et al. 2012).

Problems with training for clarity (correcting items one by one)

  • The patient has to manage articulation, speaking rate and intonation at once, which is too much to remember and hard to do.
  • It does not address the underlying problem, which is that voicing movements are too small.
  • A randomised controlled trial (RCT) comparing the two directly showed that the advantage of articulation training (LSVT ARTIC) in communication effectiveness had faded by 7 months (Ramig et al. 2018).

The logic of training for loudness (LSVT LOUD)

  • There is one target: increase the effort of voicing (that is, raise the volume).
  • When the volume goes up, clarity of articulation and the rise and fall of intonation improve as well.
  • The instruction is simple to remember, which makes it easy to remind oneself and keep applying it in daily life.

An RCT compared training for loudness (LSVT LOUD) directly with training for articulation (LSVT ARTIC). The loudness group improved significantly in how well their speech could be understood (intelligibility, by an absolute value of about 31%). This was significantly better than the articulation group (a difference of about 26.2%, p=0.04) and the no-treatment group (a difference of about 42.8%, p=0.0002) (Levy et al. 2020). Training for loudness did more than make the voice louder, because it also improved whether the patient could be understood. This is the strongest evidence for training for loudness and not for clarity.

  1. 1
    Sustained vowel
    Hold the sound "ah" for as long as possible at maximum volume, to train the strength of breath support and vocal cord closure.
  2. 2
    Pitch glides
    Slide with effort from the lowest note up to the highest and back down, to train the range of pitch change and the flexibility of the larynx, and to improve flat intonation.
  3. 3
    Functional phrases
    Practise speaking loudly with everyday sentences (for example introducing oneself or asking for directions), to apply the training in real communication.
  4. 4
    Daily volume monitoring
    Learn to notice one's own volume and, when talking, deliberately stay at a level that feels too loud.

Clinical research evidence for LSVT LOUD

LSVT LOUD (Lee Silverman Voice Treatment, named after the first patient treated) was developed by the team of Dr Lorraine Ramig. It is one of the speech interventions for Parkinson's disease with the most randomised controlled trial evidence. The standard course is 4 sessions a week for 4 weeks, 16 sessions in all, each about 60 minutes, plus daily voice practice at home. This intensity is part of why it works, and it is based on the principle of neuroplasticity (Fox et al. 2012).

2 years
The effect of LSVT was clearly better than breathing therapy alone (RET). The gains in volume (sound pressure level, SPL) and pitch variation were still present after 2 years.
Ramig et al. 2001
About 31% increase
LSVT LOUD clearly raised how well the patient could be understood (intelligibility), and the effect was clearly better than articulation training (LSVT ARTIC) and no treatment.
Levy et al. 2020
−8.0 points / −9.6 points
In a large three-arm RCT of 388 people, the improvement in self-rated voice handicap (VHI) with LSVT LOUD at 3 months was clearly greater than with no treatment (−8.0) and with usual UK NHS speech therapy (−9.6) (P<0.001).
Sackley et al. 2024 (PD COMM)

The PD COMM study published in the BMJ in 2024 (Sackley et al. 2024) is the newest and largest evidence. In a three-arm RCT of 388 people, LSVT LOUD improved self-rated voice handicap (VHI) significantly more than no speech therapy and more than usual UK NHS speech therapy. There was no significant difference between usual NHS speech therapy and no treatment. This moved the statement that LSVT LOUD is better than usual speech therapy from small trials to large-trial evidence.

Expectations should be reasonable.LSVT LOUD has three limits: (1) Parkinson's disease keeps progressing, so regular booster sessions are usually needed to keep the benefit; (2) the course is intensive (4 weeks, 16 sessions, plus daily practice at home), which takes real commitment; (3) a small number of people feel tension or discomfort in the vocal cords early in training, and the therapist has to adjust the effort. The earlier Cochrane systematic review (Herd et al. 2012) could not decide which speech therapy is best, because the trials it included were small, but it noted that LSVT LOUD raised volume more than LSVT ARTIC and breathing therapy. Recent large RCTs (such as PD COMM) have greatly strengthened the evidence.

The difference between LSVT LOUD and LSVT BIG

Another training with a similar name is LSVT BIG. Both are based on the same principle of enlarging the size of movement, but they apply to different things: LSVT LOUD is for voicing, and LSVT BIG is for large movements of the whole body (walking, turning, stretching and so on), and is led by physiotherapists (Fox et al. 2012). This page covers voicing only.

Daily voice exercises at home

Whether the benefit of LSVT LOUD lasts depends largely on the daily maintenance practice at home after the formal course (use it or lose it). The common exercises at home are listed below. Before starting, it is better for a speech therapist to assess, demonstrate and set the intensity, to avoid using the wrong effort or tiring the vocal cords.

  • Hold the vowel "ah"—Hold the sound "ah" as long as possible with a steady, loud voice, for at least 5 seconds each time, and repeat 5 to 10 times. This trains the vocal cords to keep working and builds breath support.
  • Highest and lowest pitch practice—Slide from a low note up to a high note and then from the high note down to the low note, and repeat 5 to 10 times. This widens the pitch range and improves flat, monotone intonation.
  • Deliberately loud in conversation—In everyday situations (for example talking with family, reading the newspaper aloud or making a phone call), deliberately speak at a volume that feels too loud. This is the most important step, because it brings the training into real conversation.
  • Record, compare and recalibrate—Record the volume that feels right on a mobile phone and play it back, to help the brain recalibrate what a normal volume is.
Daily voice practice checklist at home
  • Hold the vowel "ah" at the largest steady volume, 5 to 10 times.
  • Practise sliding between the highest and lowest pitch, 5 to 10 times.
  • In daily conversation, deliberately keep to a volume that feels too loud.
  • Record and play back, to recalibrate the sense of one's own volume.
  • If the volume clearly declines within a week or two, contact the speech therapist as soon as possible for a review or a booster session.

A short introduction to SPEAK OUT!

Besides LSVT LOUD, another voice training for Parkinson's disease that is mentioned more often in recent years is SPEAK OUT!. It was developed by the Parkinson Voice Project. Its core idea is to turn speaking from an automatic movement into speaking with intent, which means speaking with a purpose every time the patient opens their mouth instead of speaking without thinking. In practice it also stresses effortful voicing, combines pitch and functional speech exercises, and gives weight to long-term group maintenance sessions (known as the LOUD Crowd). For some patients, speaking with intent is easier to grasp than simply being loud. Which programme to use should be advised by a speech therapist after an individual assessment.

When to seek help from a speech therapist

The principle is simple: the earlier the better. Starting training while the nervous system still has good neuroplasticity gives better results that are easier to keep. It is not necessary to wait until the voice cannot be heard at all and social life is affected. The gap is large in reality. Research estimates that about 75% to 90% of people with Parkinson's disease have speech problems, but only about 3 to 4% actually receive speech therapy (Moya-Galé & Levy 2019). Most patients are not referred, the problem is taken as an unavoidable part of ageing, and the most useful time for intervention is missed.

Signs that an assessment is worthwhileClearly quieter speech, flat and monotone intonation, others often asking for repetition, or tiring after a couple of sentences are all signs that an assessment should be arranged. They do not mean that a diagnosis has been made.
How is this arranged in Hong Kong?Patients can be referred to a speech therapist through the Hospital Authority neurology or rehabilitation departments, or can seek help from private and community services (for example the Hong Kong Parkinson's Disease Association (HKPDA) provides patient peer support and information, the Hong Kong Society for Rehabilitation and others provide community support, and there are speech therapy centres). Hong Kong also has therapists with LSVT LOUD certification.
Why does home speech therapy suit the LSVT approach?Waiting times in public hospitals are fairly long, and public awareness of this area is limited. LSVT stresses deliberately speaking loudly in daily life, with the family taking part. Practising at home in front of the family is closest to the aim of this training.

Speech therapists at Nova Health can see the patient at home. More information is on our home speech therapy page.

Frequently asked questions

Speech in Parkinson's disease is getting quieter. Is the throat deteriorating or the vocal cords damaged?
In most cases the throat itself is not damaged. Quiet speech in Parkinson's disease (called hypophonia in medicine) mainly comes from a calibration error in the brain about the size of movement and the volume needed. The brain underestimates how much effort speaking needs, so the voice becomes quieter automatically even when the patient is already trying hard. Research shows that nearly 90% of people with Parkinson's disease develop this kind of hypokinetic dysarthria, and it is often one of the earliest signs. A weaker voice is a problem of nerve signals. It is not caused by a lack of breath or by an ageing throat, so it needs targeted voice training.
Why does the patient not notice the quiet voice, while the family keeps saying "speak up"?
This is the core of the voice problem in Parkinson's disease, and it is called inaccurate internal calibration. Research found that people with Parkinson's disease have a biased perception of how loud they are. They feel that they are speaking at a normal or even loud volume, but the measured sound pressure level is clearly low. The patient is not unwilling to speak up. The brain's volume meter is reading wrongly. One focus of treatment is to recalibrate this internal meter through repeated practice and listening to recordings. For others to hear comfortably, the patient has to feel that the voice is "too loud".
Should the patient train for clear speech or for loud speech?
The evidence clearly supports training for loudness. LSVT LOUD uses a single target: it increases only the effort of voicing (volume) and does not correct articulation, speaking rate and intonation one by one. When the overall effort of voicing increases, breathing, the vocal cords and articulation improve together, and volume, clarity and intonation get better as well. A randomised controlled trial compared training for loudness (LSVT LOUD) directly with training for articulation (LSVT ARTIC). The loudness group was significantly better at being understood, and the effect lasted longer. With only one target, loudness, the patient finds it easier to remind themselves and keep applying it in daily life.
Does LSVT LOUD really work? How long does the benefit last?
Among speech therapy methods, LSVT LOUD is one of those with the strongest evidence. Several randomised controlled trials (RCTs) found that it clearly raises volume and improves how well the patient is understood, with effects lasting 12 to 24 months. A large RCT of 388 people in 2024 (PD COMM) also showed that it improved patient-rated voice disability significantly more than usual speech therapy or no treatment. There are three limits: (1) Parkinson's disease keeps progressing, so regular booster sessions are usually needed to keep the benefit; (2) the course is intensive (4 weeks, 16 sessions, plus daily practice at home), which takes real commitment; (3) a small number of people feel tension or discomfort in the vocal cords early in training, and the therapist needs to adjust the effort. An early Cochrane review could not reach a conclusion because the trials were small, and recent large RCTs have greatly strengthened the evidence.
What voice exercises can be done at home?
Beyond the formal course, daily practice at home is the key to keeping the benefit (use it or lose it). Common exercises are: (1) holding the vowel "ah" as long as possible with a steady, loud voice, to train the vocal cords to keep working; (2) highest and lowest pitch practice, sliding from low to high and back down, to widen the pitch range and improve flat intonation; (3) deliberately speaking loudly in daily conversation, using a volume that feels "too loud" when talking to people, reading the newspaper aloud or making phone calls, to bring the training into real situations. Practise every day and with effort, and compare with recordings to recalibrate the sense of one's own volume. Practising alone can mean using the wrong effort or tiring the vocal cords, so it is better for a speech therapist to assess, demonstrate and set the intensity first, and for the patient to continue at home afterwards.
When should a speech therapist be involved? How is this arranged in Hong Kong?
The earlier the better. Intervening while the nervous system still has good neuroplasticity gives better results that are easier to keep. It is not necessary to wait until the voice cannot be heard at all and social life is affected. If the patient's voice becomes quieter, the intonation becomes flat, or others often ask for repetition, an assessment is worthwhile. In Hong Kong, a referral to a speech therapist can be made through the Hospital Authority neurology or rehabilitation departments, or help can be sought from private and community services (the Hong Kong Parkinson's Disease Association (HKPDA) provides patient peer support and information, community support is available from organisations such as the Hong Kong Society for Rehabilitation, and there are speech therapy centres). Hong Kong also has therapists with LSVT LOUD certification. Waiting times in public hospitals are long and public awareness is limited. Home speech therapy takes place in the patient's own home with family involved, which fits the LSVT emphasis on practice in everyday situations.

Disclaimer: This article is general health information and is not professional medical advice. If you have any health concerns, please consult a qualified healthcare professional.

References

  1. Ramig, L. O., Sapir, S., Countryman, S., Pawlas, A. A., O'Brien, C., Hoehn, M., & Thompson, L. L. (2001). Intensive voice treatment (LSVT) for patients with Parkinson's disease: a 2 year follow up. Journal of Neurology, Neurosurgery & Psychiatry, 71(4), 493–498. PubMed (PMID 11561033)
  2. Ramig, L., Halpern, A., Spielman, J., Fox, C., & Freeman, K. (2018). Speech treatment in Parkinson's disease: Randomized controlled trial (RCT). Movement Disorders, 33(11), 1777–1791. PubMed (PMID 30264896 / DOI 10.1002/mds.27460)
  3. Levy, E. S., Moya-Galé, G., Chang, Y. H. M., Freeman, K., Forrest, K., Brin, M. F., & Ramig, L. A. (2020). The effects of intensive speech treatment on intelligibility in Parkinson's disease: A randomised controlled trial. eClinicalMedicine, 24, 100429. PubMed (PMID 32639484 / DOI 10.1016/j.eclinm.2020.100429)
  4. Sackley, C. M., Rick, C., Brady, M. C., Woolley, R., Burton, C., Patel, S., … Clarke, C. E. (2024). Lee Silverman voice treatment versus NHS speech and language therapy versus control for dysarthria in people with Parkinson's disease (PD COMM): a pragmatic, UK based, multicentre, three arm, parallel group, unblinded, randomised controlled trial. BMJ, 386, e078341. PMC (DOI 10.1136/bmj-2023-078341)
  5. Fox, C., Ebersbach, G., Ramig, L., & Sapir, S. (2012). LSVT LOUD and LSVT BIG: Behavioral Treatment Programs for Speech and Body Movement in Parkinson Disease. Parkinson's Disease, 2012, 391946. PMC (DOI 10.1155/2012/391946)
  6. Clark, J. P., Adams, S. G., Dykstra, A. D., Moodie, S., & Jog, M. (2014). Loudness perception and speech intensity control in Parkinson's disease. Journal of Communication Disorders, 51, 1–12. PubMed (PMID 25194745 / DOI 10.1016/j.jcomdis.2014.08.001)
  7. Herd, C. P., Tomlinson, C. L., Deane, K. H. O., Brady, M. C., Smith, C. H., Sackley, C. M., & Clarke, C. E. (2012). Comparison of speech and language therapy techniques for speech problems in Parkinson's disease. Cochrane Database of Systematic Reviews, 2012(8), CD002814. PubMed (PMID 22895931 / DOI 10.1002/14651858.CD002814.pub2)
  8. Moya-Galé, G., & Levy, E. S. (2019). Parkinson's disease-associated dysarthria: prevalence, impact and management strategies. Journal of Research and Reviews in Parkinsonism, 9, 9–16. Dove Press (DOI 10.2147/JPRLS.S168090)