RESUMO
Purpose. Persons with Parkinson disease (PD) demonstrate deficits in motor learning as well as bidirectional interference (the performance of one task concurrently interferes with the performance of another task) during dual-task performance. Few studies have examined the practice dosages necessary for behavioral change in rehabilitation relevant tasks. Therefore, to compare the effects of age and PD on motor learning during dual-task performance, this pilot study examined persons with PD as well as neurologically healthy participants during concurrent performance of postural and speaking tasks. Methods. Seven persons with PD and 7 healthy age-matched and 10 healthy young control subjects were tested in a motion capture facility. Task performances were performed concurrently and recorded during 3 time periods (acquisition (beginning and ending), 48-hour retention, and 1-week retention). Postural control and speech articulatory acoustic variables were measured. Results. Healthy young participants consistently performed better than other groups on all measured postural and speech variables. Healthy young participants showed decreased variability at retention, while persons with PD and healthy age-matched controls were unable to consistently improve their performance as a result of practice. No changes were noted in the speech variables. Conclusion. The lack of consistent changes in motor performance in any of the tasks, except in the healthy young group, suggests a decreased efficiency of motor learning in the age-matched and PD groups and argues for increased practice dosages during balance training.
RESUMO
Because people frequently talk while engaged in other activities, and because Parkinson's disease (PD) is known to diminish multi-tasking performance, this study examined dual task interference between speaking and postural stability in nine individuals with PD, seven age-matched, and 10 healthy young controls. Participants repeated a target utterance and performed a rise to toes task in both single and dual task conditions. Diphthong transitions were measured from audio recordings and postural variables reflecting planning, coordination, and stability were derived from a multi-camera motion capture system and force plate recordings. Thus, sensitive measures of both speech and postural control were obtained. The group with PD performed more poorly than both control groups for the isolated postural task, but their single task speech measures did not differ from the controls, in spite of listener ratings which indicated mild-to-moderate dysarthria severity. The group with PD showed evidence of bidirectional dual task interference in that there were reduced diphthong extents and slopes along with smaller, slower, and less stable postural movements. These results indicate that concurrent performance of speech and a challenging postural control task impairs speech and postural stability in persons with PD and may result in greater risk during daily activities.
