Parkinsonian speech disfluencies: Effects of L-dopa-related fluctuations
Journal of Fluency Disorders
Goberman, A.M. & Blomgren, M. (2003) Parkinsonian speech disfluencies: Effects of L-dopa-related fluctuations Journal of Fluency Disorders, 28(1), 55-70
As Parkinson’s disease (PD) patients commonly exhibit changes in the dopamine levels (a neurotransmitter [a chemical] in the brain that affects the control of movement) accompanied by changes in motor performance, the present study examined disfluency (not having fluent speech) in PD patients to gain information on the role of dopamine in speech abnormalities. Nine PD patients with no history of developmental stuttering were recorded once before and twice after taking their morning medication (on separate days). They read a passage and produced a monologue. Within-word and overall speech disfluencies were calculated at each recording. Through motor testing, it was inferred that participants had relatively low dopamine levels before taking medication and relatively high dopamine levels after taking medication. There were no group changes in disfluency levels when the low-dopamine and high-dopamine states were compared. There were, however, significant differences in disfluencies between the PD participants and age-matched controls. The results of this study do not strongly support that excess dopamine influences stuttering.