title: Trunk-arm coordination in reaching for moving targets in people with Parkinson's disease: comparison between virtual and physical reality.
abstract: We used a trunk-assisted prehension task to examine the effect of task (reaching for stationary vs. moving targets) and environmental constraints (virtual reality [VR] vs. physical reality) on the temporal control of trunk and arm motions in people with Parkinson's disease (PD). Twenty-four participants with PD and 24 age-matched controls reached for and grasped a ball that was either stationary or moving along a ramp 120% of arm length away. In a similar VR task, participants reached for a virtual ball that was either stationary or moving. Movement speed was measured as trunk and arm movement times (MTs); trunk-arm coordination was measured as onset interval and offset interval between trunk and arm motions, as well as a summarized index-desynchrony score. In both VR and physical reality, the PD group had longer trunk and arm MTs than the control group when reaching for stationary balls (p<.001). When reaching for moving balls in VR and physical reality, however, the PD group had lower trunk and arm MTs, onset intervals, and desynchrony scores (p<.001). For the PD group, VR induced shorter trunk MTs, shorter offset intervals, and lower desynchrony scores than did physical reality when reaching for moving balls (p<.001). These findings suggest that using real moving targets in trunk-assisted prehension tasks improves the speed and synchronization of trunk and arm motions in people with PD, and that using virtual moving targets may induce a movement termination strategy different from that used in physical reality.
authors.affiliation: Department of Occupational Therapy, College of Medicine, National Cheng Kung University, Taiwan. huingma@mail.ncku.edu.tw
authors.forename: Hui-Ing
authors.initials: HI
authors.lastname: Ma
authors.forename: Wen-Juh
authors.initials: WJ
authors.lastname: Hwang
authors.forename: Ching-Yi
authors.initials: CY
authors.lastname: Wang
authors.forename: Jing-Jing
authors.initials: JJ
authors.lastname: Fang
authors.forename: Iat-Fai
authors.initials: IF
authors.lastname: Leong
authors.forename: Tsui-Ying
authors.initials: TY
authors.lastname: Wang
mesh_terms: D000368:Aged; D001132:Arm / Q000503:physiopathology; D001259:Ataxia / Q000503:physiopathology* / Q000534:rehabilitation; D001479:Basal Ganglia / Q000503:physiopathology; D001696:Biomechanical Phenomena / Q000502:physiology; D005260:Female; D005556:Form Perception / Q000502:physiology*; D018737:Hand Strength / Q000502:physiology*; D006801:Humans; D007699:Kinesthesis / Q000502:physiology; D008297:Male; D008875:Middle Aged; D009039:Motion Perception / Q000502:physiology*; D009048:Motor Skills / Q000502:physiology; D009949:Orientation / Q000502:physiology*; D010300:Parkinson Disease / Q000503:physiopathology* / Q000534:rehabilitation; D011597:Psychomotor Performance / Q000502:physiology*; D011930:Reaction Time / Q000502:physiology; D014584:User-Computer Interface