Clinical evaluation of Parkinson's-related dysphonia

Abstract

Objectives: Nearly one third of patients with idiopathic Parkinson's disease (IPD) cite dysphonia, characterized subjectively as causing a harsh and breathy voice, as their most debilitating deficit. Medical or behavioral treatments may lead to voice improvement. The purpose of this study was 1) to determine whether vocal fold injection of Cymetra (micronized form of collagen, elastin, proteoglycans; Lifecell Co.) is associated with changes in dysphonic voice characteristics in subjects with IPD, as judged perceptually using a standard instrument Consensus Auditory-Perceptual Evaluation of Voice (CAPE-V), and (2) which acoustic and aerodynamic measurements of voice are most reflective of any observed perceptual changes in voice.

Study design: Prospective clinical evaluation of patients with Parkinson's-related dysphonia (PRD).

Methods: Six patients with PRD were evaluated before treatment for the presence of dysphonia and glottal gap. All subjects underwent transoral vocal fold collagen injection using topical anesthesia in the otolaryngology clinic as part of their clinical care. At the initial clinic visit, and 10 to14 days after vocal fold collagen injection, patients were asked to complete the Voice Handicap Index (VHI), a questionnaire concerning voice-related quality of life, and perceptual analyses of voice quality were performed. In addition, patients underwent acoustic (pitch/loudness range, maximum phonation time [MPT], and aerodynamic phonation threshold pressure [PTP]) voice analysis.

Results: Five of six subjects had self-perceived improvements in voice after treatment, as determined by the VHI (range, +8 to -24). All five subjects who completed testing demonstrated decreased PTP (range, -1.3 to -2.7, P = .002). Five of six subjects demonstrated statistically significant improvements in MPT (range, -2-16 s, P = .05). Five of six subjects had improved pitch range (-26-343 Hz), whereas all subjects had increased intensity range (0.6-23 db) after injection.

Conclusions: Transoral collagen injection in patients with PRD is safe, well tolerated, and is an effective temporary method of subjectively improving voice and speech in selected patients with IPD. Reduction of glottal gap with collagen improves MPT and subglottal PTP. The resulting gain of vocal efficiency may reduce vocal fatigue and provide a useful adjunct to voice therapy for PRD.