Effects of LSVT LOUD and EMST in individuals with Parkinson's disease: A two arm non-randomized clinical trial

This study compared the effects of Lee Silverman Voice Treatment and Expiratory Muscle Strength Training on swallow, cough, and voice function in individuals with Parkinson's disease.

Fifty-eight individuals with mild-moderate Parkinson's disease (male = 45, M = 69 years, SD = 8) were enrolled in a two-treatment clinical trial and completed four consecutive weeks of either Lee Silverman Voice Therapy or Expiratory Muscle Strength Training. All participants completed standard protocol videofluoroscopic swallow study, spirometry-cough tests, acoustic-voice assessment, and self-rated questionnaires pre- and post-therapy. Data were analysed by masked clinicians using specialised software. Mixed-model repeated measures and t-tests were performed.

Lee Silverman Voice Treatment resulted in greater effects in acoustic aerodynamic voice measures (loudness, pitch-range, and aerodynamic-efficiency; p < .05) compared to the Expiratory Muscle Strength Training group. There were significant effects on pharyngoesophageal segment maximum opening (p =.01) following Lee Silverman Voice Treatment. Expiratory Muscle Strength Training resulted in significantly greater change in maximum hyoid displacement (Hmax; p = .04) and decreased Hmax duration (p < .01) compared to Lee Silverman Voice Therapy group. No cough measures and self-reported questionnaires significantly differed between groups with both groups improving post-treatment.

Both Lee Silverman Voice Therapy and Expiratory Muscle Strength Training improved specific swallow efficiency and airway defence capacity despite differences in task and therapeutic dose. Only Lee Silverman Voice Thearpy improved vocal intensity. Both treatments are feasible options for individuals with mild-moderate Parkinson's disease.