Voice therapy gives Parkinson’s patients a new life

A study published in the BMJ has demonstrated the effectiveness of Lee Silverman’s voice therapy (LSVT LOUD) in Parkinson’s patients and shown that it provides more benefits than conventional therapy through the public health system or no therapy at all.

New research shows that Lee Silverman’s speech therapy (LSVT LOUD) has a significant positive effect on speech and communication in Parkinson’s patients, compared to standard NHS treatment or no treatment at all. Despite some cases of voice problems, there is an improvement in quality of life.

An intensive voice treatment developed in the US and known as Lee Silverman Voice Treatment (LSVT LOUD) is more effective for Parkinson’s patients than traditional NHS speech and language therapy or no therapy at all, according to a study published today (10 July) in The BMJ.

According to the researchers, the results underscore the need to optimize the use of speech and language therapy resources for people with Parkinson’s disease.

A common symptom of Parkinson’s disease is slurred or slow speech (dysarthria). It can significantly impair communication and potentially lead to stigma, social isolation and a reduced quality of life.

Two approaches are available in the UK, such as NHS speech and language therapy or Lee Silverman’s voice treatment (LSVT LOUD), but there is no conclusive evidence of their effectiveness.

Study design and first results

To address this issue, researchers investigated the clinical effectiveness of these two speech therapy approaches compared to no therapy for dysarthria in Parkinson’s patients.

Their findings are based on 388 people with Parkinson’s disease and dysarthria (74% male; about half aged 70 or over) who were randomly assigned to one of three groups from September 2016 to March 2020: 130 to LSVT LOUD, 129 to NHS speech and language therapy, and 129 to no speech and language therapy.

Comparison of therapy results

LSVT LOUD consisted of four 50-minute sessions per week delivered in person or remotely over a four-week period, plus home-based practice activities (5–10 minutes daily on treatment days and 15 minutes twice daily on non-treatment days).

The number of NHS speech and language therapy sessions was decided by the local therapist according to the patient’s needs (an average of one session per week for six to eight weeks).

All participants reported their Voice Impairment Index score after three months – a measure of the impact of communication difficulties on a scale of 0 to 120 (with a low score being positive).

Patients receiving LSVT LOUD had voice impairment scores 8 points lower (ie, better) at three months than those who did not receive speech and language therapy, and almost 10 points lower than those who received speech and language therapy through the NHS.

Limitations of the study and long-term results

There was no difference in voice impairment scores between NHS speech and language therapy and no speech and language therapy.

In the LSVT-LOUD group, 93 adverse events (mainly voice strain) were reported, in the NHS therapy group 46 and in the no therapy group none. No serious adverse events were registered.

Voice impairment outcomes at six and twelve months were similar to those in the main analysis. Patients receiving LSVT LOUD also experienced a clinically meaningful benefit in quality of life related to communication.

The researchers point out some limitations of the study. For example, most participants were in the early stages of Parkinson’s disease and had mild speech disorders, which may not reflect all Parkinson’s patients who require speech therapy. Blinding the study was also not feasible, which may have influenced the results.

Nevertheless, they conclude: “This randomized trial provides evidence that can guide clinical decisions and highlights the need to optimize the use of speech and language therapy resources for people with Parkinson’s disease.”

Editorial insights and future directions

This study convincingly shows that LSVT LOUD is the most clinically effective speech treatment for this patient group, say experts in a linked editorial.

However, they note that the intensive nature of LSVT LOUD treatment raises access issues and impacts on service delivery, and believe that further research is needed to support patients for whom LSVT LOUD is not appropriate.

“The challenges of this study include how to ensure that health systems with limited resources can implement effective, evidence-based innovations and how patient groups can best advocate for this with health system decision-makers,” she concluded.

Reference: “What is the clinical effectiveness of Lee Silverman Voice Treatment (LSVT LOUD®), NHS speech and language therapy (SLT), compared with no speech and language therapy for dysarthria in people with Parkinson’s disease?” 10 July 2024, The BMJ.
DOI: 10.1136/bmj-2023-078341

Funding: National Institute for Health Research, Health Technology Assessment Program.