Effect of expiratory muscle strength training on voice and speech: An exploratory study in persons with Parkinson's disease or multiple sclerosis.

Purpose: This study explored how respiration, voice, and speech were affected following expiratory muscle strength training (EMST) and maintenance training in persons with Parkinson's disease (PD) or multiple sclerosis (MS).

Method: Nine participants with PD and six with MS participated in a randomised study, where the effects of EMST, sham, and maintenance treatment were investigated. Outcome measures included maximum expiratory pressure (MEP); maximum phonation time (MPT); intelligibility; verbal diadochokinesis (DDK); speech rate; a self-report form on voice, speech, and communication; and open questions about how the participants experienced the intervention.