Voice analysis and videolaryngostroboscopy in patients with Parkinson's disease

Parkinson's disease (PD) is clinically characterized by a resting tremor, bradykinesia, cogwheel phenomenon, rigidity, disorder of postural reflexes and especially changes in voice and speech. We studied 30 PD patients who were treated with dopamine and 20 normal subjects as the control group. The parameters of vocal fold edges, glottal closure, vertical levels of cords, amplitude of vibration, mucosal wave, vibratory behavior, phase symmetry, ventricular folds and movements, periodicity, arytenoids and thick mucous were evaluated by videolaryngostroboscopy. The Unified Parkinson's Disease Rating Scale was applied to the patient group. The voices of the patients were evaluated by the Dr.Speech-4 and Spectra-PRO computer programs. Maximum phonation time, fundamental frequency, amplitude and the harmonic-to-noise ratio were recorded and compared with those of the control group. The abnormal videolaryngostroboscopic findings were more frequent in the PD group (70% versus 45%; P<0.05). Voice analysis showed significant differences in the parameters such as maximum phonation time, maximum fundamental frequency, the frequency range and the harmonic-to-noise ratio. We thought that these methods and parameters yielded sufficient information for diagnosis and follow-up of vocal function in patients with PD.