Kinematics of fast hemiparetic aiming movements toward stationary and moving targets

Citation
E. Van Thiel et al., Kinematics of fast hemiparetic aiming movements toward stationary and moving targets, EXP BRAIN R, 132(2), 2000, pp. 230-242
Citations number
33
Categorie Soggetti
Neurosciences & Behavoir
Journal title
EXPERIMENTAL BRAIN RESEARCH
ISSN journal
00144819 → ACNP
Volume
132
Issue
2
Year of publication
2000
Pages
230 - 242
Database
ISI
SICI code
0014-4819(200005)132:2<230:KOFHAM>2.0.ZU;2-U
Abstract
The aim of the present study was to gain insight into the control that hemi paretic subjects have over fast, unimanual aiming movements. Twelve hemipar etic subjects with cerebral palsy and twelve healthy subjects were asked to hit, as quickly as possible, stationary and moving targets projected onto a frontoparallel screen. The task was performed with the nonpreferred (spas tic/nondominant) and preferred (nonspastic/dominant) arm. Although the patt ern of kinematics of hemiparetic subjects generally corresponded with that reported in earlier reaching and grasping studies, the commonly observed pr olonged movement time of the nonpreferred arm as compared to the preferred arm was absent. The spatial variability of the lateral hand displacements t oward stationary targets was highest in the spastic arm of the hemiparetic subjects, indicating diminished motion stability. Even though hemiparetic s ubjects were expected to be unable to adjust their movements flexibly to th e position and the velocity of a moving target, they used an initial estima te of where moving targets would be hit in the same way as the healthy subj ects did, i.e., they started aiming toward a position in front of the targe t. In both subject groups, this spatial estimate and the movement time (MT) varied as a function of target velocity, suggesting that the use of target -velocity information in hitting moving targets is unaffected in spastic he miparetic subjects. The results are related to possible deficits in the reg ulation of cocontraction underlying movement stability.