Jaw and Finger Movements during Visual and Auditory Motor Tracking in Parkinsonís Disease

S Adams, M Jog, T Eadie, A Dykstra,G Gauthier, JL Vercher


The purpose of the present study was to compare oral (jaw) and upper limb (finger) movements in subjects with Parkinsonís disease (PD) using several equivalent auditory and visual motor tracking tasks. Ten PD subjects and 10 normal controls (NC) used their jaw and index finger to track visual targets on a computer screen and auditory targets (continuous 300-1100 Hz tones) through a set of headphones.These auditory and visual 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 of inferior-superior jaw and finger movements (20 mm) were also examined.Performance measures included, response time, repetition rate, and average tracking error (RMS-based procedure). For the comparisons between PD and NC subjects, significant differences were found for most of the tasks and measures that were examined (Mann-Whitney, p < .05). For the primary interaction analyses of interest([PD jaw Ė NC jaw] versus [PD finger Ė NC finger]) no significant differences were observed.In general, these results support the hypothesis that speech/oral motor deficits are very similar to limb motor deficits in PD. These results also emphasize the importance of equating motor tasks when comparing across different systems (ie. limb vs. speech/oral, gait vs. upper limb).