Objective voice changes in nondysphonic Parkinson's disease patients.

Objective: To obtain objective acoustic analysis results from Parkinson's disease patients who do not have voice symptoms and to compare these results with those from age- and sex-matched control subjects.

Design: Prospective.

Setting: Tertiary reference hospital.

Method: The objective acoustic analysis results from 14 female Parkinson's disease patients with no voice symptoms were compared with those of 22 age- and sex-matched normal subjects.

Results: Statistical analysis revealed no differences in mean fundamental frequency and shimmer values. However, differences in jitter values, loudness, and the harmonics to noise ratio were statistically significant between the two groups (p < .05).

Conclusion: With this study, it was shown that Parkinson's disease patients who do not have any voice symptoms have objectively different acoustic values than their age- and sex-matched controls. Clinicians must be aware of these initial findings on the voice changes of Parkinson's disease patients.