The effects of intensive speech treatment on intelligibility in Parkinson's disease: A randomised controlled trial

Abstract

Background: More than 6,000,000 individuals worldwide are diagnosed with Parkinson's disease (PD). Nearly 90% develop speech signs that may substantially impair their speech intelligibility, resulting in losses in their communication and quality of life. Benefits of intensive speech treatment have been documented for a range of speech signs. However, the critical question of whether speech is more intelligible after treatment has not been investigated in a randomised controlled trial (RCT). We hypothesised that intensive speech treatment would improve speech intelligibility in PD. Method: Sixty-four patients with hypokinetic dysarthria secondary to PD participated in this single-centre, parallel arm, statistically-powered RCT. Reporting follows CONSORT guidelines for non-pharmacological treatment. Patients were recruited from US clinics and randomised using a statistician-derived minimisation algorithm, to intensive speech treatment (16 1-hour sessions/1 month) targeting voice (voice group) or targeting articulation (articulation group) or to an untreated group (no treatment group). Speech treatments were delivered by speech clinicians who specialised in treating patients with PD. Trial design minimised bias and supported equipoise. For intelligibility assessment, blinded listeners (n = 117) orthographically transcribed 57 patients' recorded, self-generated narrative speech samples, randomly presented in multi-talker babble noise. Listeners were American-English speakers, ages 18À35 years, with normal hearing. The primary outcome was baseline (pre-treatment) to post-treatment change in transcription accuracy (TA), recognised as the most objective measure of intelligibility. TA was defined as the percentage of words transcribed correctly. Listeners, data collectors, and data managers were blinded to treatment conditions and groups. Reliability was evaluated using intraclass correlation coefficients and differences amongst groups were evaluated by mixed-effects models, in accordance with the intention-to-treat approach. This trial was registered with ClinicalTrials.gov Identifier: NCT00123084. Findings: Between June 23, 2016 and August 14, 2017, blinded listeners transcribed baseline and post-treatment speech samples for intelligibility assessment of 57 patients in the voice (n = 19), articulation (n = 19) and no treatment (n = 19) groups. Between-group differences (d) in changes from baseline to post-treatment in TA indicated significantly greater increases following treatment targeting voice than treatment targeting articulation (d = 26¢2%, 95% CI 1¢5 À 51¢0; p = 0¢04; ES=1¢0). Differences between TA changes in the treatment targeting voice and in the no treatment group were significant (d = 42¢8%, 95% CI 22¢4 À 63¢2; p = 0¢0002; ES=1¢8). Differences between TA changes in the treatment targeting articulation and in the no treatment group were not significant (d = 16¢5%, 95% CI -6¢1 À 39¢2; p = 0¢147; ES=0¢9).

Speech Treatment Effects on Narrative Intelligibility in French-Speaking Children With Dysarthria

“…Transcription accuracy, considered an objective measure of intelligibility (Hustad, 2006), was calculated as percentage of words correctly transcribed. Orthographic transcriptions were considered correct if words matched the target exactly or if differences were due to homonyms or obvious misspellings (Cannito et al, 2012;Hustad, 2007;Levy, Moya-Galé, Chang, Freeman, et al, 2020). Mean naturalness ratings were calculated from the VAS responses.…”

Non-pharmacological Treatment Challenges in Early Parkinson's Disease for Axial and Cognitive Symptoms: A Mini Review

“…Only one RCT is available on the rehabilitation effect specifically for early PD patients. Levy and colleagues ( 18 ) found that only the high-intensity voice treatment, Lee Silverman Voice Treatment (LSVT) LOUD®, resulted in significant improvements in intelligibility for patients with mean H&Y 2.1. This was compared to patients receiving a high-intensity articulation treatment or no treatment.…”

Speech and language therapy treatment on hypokinetic dysarthria in Parkinson disease: Systematic review and meta-analysis

“…The quality assessment using the Downs and Black scale shows high quality for 7 22,27,29–33 of the included studies and fair for 8 21,24–29,34,35 of the studies. However, when Cochrane Risk of bias Assessment was applied, the risk of bias shown is generally low.…”

“…Among the included studies, five studies 23,24,28,33,34 compared speech and language therapy to no treatment; and five studies 21,25–27,31 compared speech and language therapy to control treatment (Respiratory effort treatment). Additionally, four studies 29,30,32,35 included three groups, (Two different groups of speech and language therapies and a non-treatment group).…”