Prosodic Improvement in Persons with Parkinson Disease Receiving SPEAK OUT!® Voice Therapy

Hypokinetic dysarthria in Parkinson disease (PD) hinders the ability to verbally communicate and interferes with activities of daily living. SPEAK OUT!® is a therapy program designed to improve functional communicative ability. In contrast to the Lee Silverman Voice Treatment program, SPEAK OUT!® promotes speaking with intent to effect loud speech. This study evaluated the efficacy of SPEAK OUT!® in persons with idiopathic PD in 3 domains: self-reported voice handicap, clinical ratings of dysarthria and prosody, and acoustic analysis of prosody.

Pre-/post-therapy data included PD participants' scores on the Voice Handicap Index (VHI) and the Voice-Related Quality of Life (V-RQOL) questionnaire, audio recordings, perceptual evaluation scores, and demographic data, such as age, sex, handedness, diagnosis, and onset of PD.

Participants achieved a statistically and clinically significant improvement in speech intensity, pitch range, normalized pairwise variability index for pitch, sustained vowel duration, reading intelligibility, and vocal quality after SPEAK OUT!® training, consistent with both of the self-report voice scores, i.e., the VHI and the V-RQOL, and with the perceptual speech evaluation scores. Longer PD duration was associated with lowered efficacy.

SPEAK OUT!® is effective and should be administered as early as possible after disease onset.