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A multi-centre randomised controlled trial to compare the clinical and cost-effectiveness of Lee Silverman Voice Treatment versus standard NHS speech and language therapy versus control in Parkinson’s Disease


  1. To evaluate the clinical and cost-effectiveness of speech and language therapy (SLT) for people with Parkinson’s disease using three comparisons: Lee Silverman Voice Treatment (LSVT) versus control; standard NHS SLT versus control; and LSVT versus standard NHS SLT.
  2. To contextualise and interpret the PD COMM trial results.


Communication problems are a common and disabling feature of Parkinson’s disease, yet high quality randomized controlled trial evidence for the effectiveness of speech and language therapy interventions is lacking. This three-arm UK multi-site trial, developed following a successful pilot, is recruiting 546 people with Parkinson’s disease who have self or carer-reported problems with their speech or voice and no dementia. It compares two routine NHS interventions with no SLT intervention for 12 months, and with each other. The interventions are Lee Silverman Voice Treatment (a standardized program delivered in 16 sessions over 4 weeks) and other standard NHS intervention (typically weekly sessions for 6-8 weeks tailored to individual needs, incorporating impairment, compensatory, functional and alternative/augmentative communication components). All outcome measures of communication and quality of life are patient-reported (one carer-reported), including the primary outcome measure the Voice Handicap Index, with the majority completed at baseline, then 3, 6 and 12 months. Adverse events are the vocal strain or abuse. A mixed method process evaluation includes interviews with a purposive sample of participants and therapists to understand the implementation of the trial and experience of its interventions and a quantitative exploration of therapy components and their combinations.

Principal Investigator: King's College London

NMAHP Research Unit Collaborators: Professor Marian Brady

External Collaborators: Burton C - Bangor University, Clark CE - University of Birmingham,  Ives N - University of Birmingham, Jowet S - University of Birmingham, Patel S - University of Birmingham, Rick C - University of Birmingham, Smith CH - University College London.

Funder: NIHR

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