title: Task-based profile of vocal intensity decline in Parkinson's disease.
abstract: This study examines intensity decay in the phonation of persons with Parkinson's disease (PD). The decline in vocal intensity (determined by linear regression of the intensity envelope) was compared across the following tasks: vowel prolongation, syllable repetition (diadochokinesis, DDK), isolated sentences and conversation. In contrast to previous studies, PD speakers demonstrated no significant differences in intensity decline from healthy speakers in vowel prolongation. The vocal intensity of speakers with PD declined more rapidly than that of controls in DDK tasks. While intensity slopes in conversation were more variable in both groups, some participants with PD exhibited abrupt changes in intensity. Results indicate that the DDK is particularly useful for describing intensity decay associated with PD. However, considering the inconsistent group differences across tasks, and the discrepant findings from previous studies, intensity decay is not a robust symptom of PD.
authors.affiliation: Waisman Center, Madison, WI 53705, USA. rosen@waisman.wisc.edu
authors.forename: Kristin M
authors.initials: KM
authors.lastname: Rosen
authors.forename: Raymond D
authors.initials: RD
authors.lastname: Kent
authors.forename: Joseph R
authors.initials: JR
authors.lastname: Duffy
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016022:Case-Control Studies; D006801:Humans; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000150:complications / Q000503:physiopathology*; D010699:Phonation / Q000502:physiology*; D013016:Sound; D013061:Speech Acoustics; D013068:Speech Production Measurement; D014827:Vocal Cords / Q000503:physiopathology*; D014832:Voice Disorders / Q000209:etiology* / Q000503:physiopathology