The Impact of Parkinson's Disease on Breath Pauses and Their Relationship to Speech Impairment: A Longitudinal Study.

Purpose The purposes of this longitudinal study were to (a) examine the impact of Parkinson's disease (PD) progression on breath pause patterns and speech and linguistic errors and (b) determine the extent to which breath pauses and speech and linguistic errors contribute to speech impairment. Method Eight individuals with PD and eight age- and sex-matched control participants produced a reading passage on two occasions (Time 1 and Time 2) 3 years and 7 months apart on average. Two speech-language pathologists rated the severity of speech impairment for all participants at each time. Dependent variables included the location of each breath pause relative to syntax and punctuation as well as the number of disfluencies and mazes. Results At Time 1, there were no significant differences between the groups regarding breath pause patterns. At Time 2, individuals with PD produced significantly fewer breath pauses at major syntactic boundaries and periods as well as significantly more breath pauses at locations with no punctuation than control participants. Individuals with PD produced a significantly greater number of disfluencies than control participants at both time points. There were no significant differences between the groups in the number of mazes produced at either time point. Together, the number of mazes and the percentage of breath pauses at locations with no punctuation explained 50% of the variance associated with the ratings of severity of speech impairment. Conclusion These results highlight the importance of targeting both respiratory physiological and cognitive-linguistic systems in order to improve speech production in individuals with PD.