Visuomotor training improves stroke-related ipsilesional upper extremity impairments.
BACKGROUND
Unilateral middle cerebral artery infarction has been reported to impair bilateral hand grasp.


METHODS
Individuals (5 males and 5 females; age 33-86 years) with chronic unilateral middle cerebral artery stroke (4 right lesions and 6 left lesions) repeatedly lifted a 260-g object. Participants were then trained to lift the object using visuomotor feedback via an oscilloscope that displayed their actual grip force (GF) and a target GF, which roughly matched the physical properties of the object.


RESULTS
The subjects failed to accurately modulate the predictive GF when relying on somatosensory information from the previous lifts. Instead, for all the lifts, they programmed excessive GF equivalent to the force used for the first lift. The predictive GF was lowered for lifts following the removal of the visual feedback. The mean difference in predictive GF between the lifts before and after visual training was significant (4.35 +/- 0.027 N; P <or= .001; 95% confidence interval [CI] = 3.80-4.88). After removal of visual feedback, there was also a significant mean difference in the applied predictive GF between the "early" and "late" lifts (0.78 +/- 0.029 N; P <or= .006; 95% CI = 0.22-1.35), demonstrating continued increase in predictive GF accuracy.


CONCLUSIONS
Predictive or feedforward fingertip force generation is impaired in the ipsilesional hand when lifting a novel object with precision grip. Reacquisition of the motor forces for the grasp of objects is possible after stroke. Potentially, retraining grasp control for the ipsilesional hand may translate to improved function and motor learning within the contralesional hand.
Quaney
Barbara M
BM
Landon Center on Aging, Kansas University Medical Center, Kansas City, Kansas 66160, USA. bquaney@kumc.edu
He
Jianghua
J
Timberlake
George
G
Dodd
Kevin
K
Carr
Caitlin
C
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001132:Arm; D002908:Chronic Disease; D020820:Dyskinesias / Q000209:etiology / Q000534:rehabilitation*; D030141:Feedback, Psychological; D005260:Female; D007839:Functional Laterality; D018737:Hand Strength; D006801:Humans; D020244:Infarction, Middle Cerebral Artery / Q000150:complications / Q000534:rehabilitation*; D008297:Male; D008875:Middle Aged; D009043:Motor Activity; D026201:Musculoskeletal Manipulations / Q000379:methods*; D011597:Psychomotor Performance; D016896:Treatment Outcome; D014796:Visual Perception