title: Effect of video feedback on the performance of a weight shifting controlled tracking task in subjects with parkinsonism and neurologically intact individuals.
abstract: This study compared the performance of a visual motor task, accomplished by standing weight shifting, of 34 people with Parkinson's disease (P.D.) and 34 neurologically intact (N.I.) subjects. Twenty of the P.D. subjects were in Stage 1 and 14 were in Stage 2. The performance of ten, 10-s trials was each examined under two feedback (FB) conditions: continuous video display of performance and end of trial position. Visual FB was composed of displaying a target and cursor on a video monitor, with the cursor controlled by the subject through weight shifting on a platform interfaced with a microprocessor. Once the cursor was centered, the computer then transferred the target to the upper right quadrant of the monitor, and the subject was required, through weight shifting, to relocate the cursor inside the target. ANOVA with repeated measures was used for data analysis. The visual motor performance of P.D. subjects was significantly worse than that of N.I. (P less than 0.01), as well as between FB conditions (P less than 0.01). The interaction of the FB condition by trial segment was significant (P less than 0.01), as was the interaction of group membership by the trial segment (P less than 0.01). FB condition and group membership did not significantly interact, confirming that performance was worse under end of trial position FB, regardless of group membership (P less than 0.01). Post hoc analysis yielded significant differences (P less than 0.05) in task performance between N.I. and P.D. subjects after the first second of the trials regardless of FB condition. In either group, significant differences between continuous visual FB and end of trial position FB (P less than 0.05) were verified after the fourth second. Performance between N.I., Stage 1, and Stage 2 P.D. subjects revealed significant differences (P less than 0.01) among all three groups, regardless of FB condition. One of the revealing aspects of this investigation was the establishment of significant differences in visual motor performance of individuals in the early stages of the disease compared to previous reports of extremity deficits in the later stages.
authors.affiliation: Physical Therapy Program, School of Health Sciences, Hunter College, New York, New York 10010.
authors.forename: G
authors.initials: G
authors.lastname: Krasilovsky
authors.forename: J
authors.initials: J
authors.lastname: Gianutsos
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D005246:Feedback; D006801:Humans; D008875:Middle Aged; D010300:Parkinson Disease / Q000523:psychology*; D011597:Psychomotor Performance; D012016:Reference Values; D012044:Regression Analysis; D013690:Television