Voice quality in Parkinson's disease in the Croatian language speakers

Parkinson's disease (PD) is well known to cause voice impairments. The aim of this study is to evaluate subjective and objective changes in voice quality in patients with PD in Croatian language speakers. Twenty one patients (11 male and 10 female) with PD and twenty one age-matched (10 male and 11 female) of the control group were assessed. Voice impairment was scored according to Voice Handicap Index (VHI). Patient's perceptual voice analysis was assessed using GRBAS scale including Grade of Dysphonia, Roughness, Breathiness, Asthenia and Strain items. The analysed objective voice parametars were: fundamental frequency, highest frequency, lowest frequency, voice range, jitter, shimmer, maximum phonation time and s/z ratio. In all patients we performed videolaryngostroboscopic examination. Compared with the control group we found the significant differences in VHI, in GRBAS scale (p < 0.05 in all items except asthenia). On videostroboscopic examination, laryngeal tremor was present only in PD group (6 patients), abnormalities of the mucosal wave was found more frequent in PD group (17 versus 8 patients) and also non-closure glottis pattern (11 versus 6 patients). There was no significant difference in the objective voice parametars except in maximum phonation time which was shorter in PD group (15.8 seconds and 23 seconds, p = 0.014) and voice range, which was shorter in PD group (111 Hz versus 147 Hz, p = 0.0465). No one of patients with PD was included in any form of speech therapy. The voice disability in PD is generally well known, but very often underestimated. In this study we found which components of voice were more affected. The voice quality has a significant impact on life quality and potential in assessment for severity of disease state and for the efficacy of treatment.