Jaw and finger movements during visual and auditory motor tracking in Parkinson disease
Résumé
Audiomotor and visuomotor tracking paradigms were used to evaluate differences in oral and upper limb motor deficits in Parkinson disease (PD). Ten PD subjects and 10 normal controls (NC) used their jaw and index finger to track visual targets and auditory targets. Tracking tasks included (1) stationary target tracking, (2) step tracking, and (3) predictable sinusoidal (.3, .5, .8, 1.1 Hz) tracking. Maximum rates of repetition were also examined. Performance measures included response time, repetition rate, and average tracking error. PD subjects showed a significant impairment on most of the tasks and measures that were examined. None of the primary interactions were significant. These interaction results indicate that PD oral and limb movements showed (1) equivalent reductions in the speed of repetitive movements, (2) equivalent increases in visual and auditory response times, (3) equivalent difficulty in maintaining visual and auditory guided postures, and (4) equivalent difficulty in tracking predictable auditory and visual targets. In general, these results support the hypothesis that speech/oral motor deficits are similar to limb motor deficits in PD. These results also emphasize the importance of equating motor tasks when comparing across different systems (i.e., limb vs. speech/oral, gait vs. upper limb).