Effects of voice rehabilitation in people with MS: A double-blinded long-term randomized controlled trial

Hypophonia is a prevailing problem in people with multiple sclerosis (PwMS). However, evidence supporting the effectiveness of voice rehabilitation is lacking.

The aim of this study was to identify the most effective method to reduce hypophonia.

In this randomized controlled trial, 44 PwMS were randomized to intensive and high-effort voice treatment groups, the LSVT-LOUD^®, and conventional treatment group. Subjects received 16 treatments (4 sessions/week) lasting 45 minutes. The primary outcome was voice intensity (dB) in monologue, vocalization, and sentences while voice handicap index (VHI) measured voice self-perception. Outcomes were assessed by a blinded observer at baseline, post-treatment, and 15-month follow-up (FU).

Linear models revealed a significant post-intervention between-group mean difference in favor of LSVT-LOUD for monologue: +6.3 dB (95% CI: 2.5 to 10.1); vocalization: +7.4 dB (95% CI: 2.3 to 12.5); and sentences: +9.5 dB (95% CI: 4.7 to 14.3). However, 43.7% PwMS in the LSVT-LOUD and 10% in the conventional treatment group obtained a full recovery of voice intensity (>60 dB) post-treatment, Fisher's test = 13.3, p < 0.01. However, these improvements were not maintained at FU. Between-group differences at VHI were -10.8 (95% CI: -21.2 to -0.4) and -11.3 (95% CI: -24.3 to -1.7) in favor of LSVT-LOUD at post and FU.

LSVT-LOUD can be a valid treatment to increase voice intensity in PwMS. However, results suggest the need for FU interventions targeting maintenance.