Abnormal cognitive planning and movement smoothness control for a complex shoulder/elbow motor task in stroke survivors.
OBJECTIVE
Cortical function is not well understood in stroke survivors with persistent dyscoordination. The study purpose was two-fold: 1) characterize cognitive planning time and cognitive effort level for a circle-drawing motor task in stroke survivors using shoulder/elbow muscles and 2) identify the relationship between cognitive effort level and movement smoothness.


METHODS
Twelve stroke survivors with shoulder/elbow coordination deficits (>12 mo) and eight controls were enrolled. The motor task was to draw a circle on a horizontal surface using only shoulder/elbow muscles. Outcome measures were: EEG-derived cognitive planning time, cognitive effort level, and movement smoothness. Comparisons between stroke and controls were made using t-tests. The Pearson's correlation model was analyzed to determine the relationship between movement smoothness and cognitive effort level.


RESULTS
Stroke subjects showed a statistically significant prolonged motor planning time versus controls for both lesion and non-lesion sides (p=0.013 and 0.049, respectively). They also showed a statistically significant elevated effort level versus controls for both sides (p=0.016 and 0.013). The patients exhibited statistically significant poor movement smoothness in the medial/lateral and forward/backward movement directions versus controls (p=0.035 and 0.037, respectively). For stroke, there was a significant correlation between cognitive effort level on the non-lesion side and smoothness of movement in the medial/lateral and forward/backward directions (r=0.54, p=0.036 and r=0.76, p=0.002, respectively). On the lesion side, results were mixed (r=0.268, p=0.2 r=0.59, p=0.023, respectively).


CONCLUSIONS
Stroke survivors with upper limb motor deficits exhibit a longer cognitive planning time and elevated cognitive effort for performance of a complex shoulder/elbow motor coordination task. The elevated cognitive effort level was associated with poor (jerky) motor performance, suggesting a potential role of the CNS in controlling movement smoothness of the arm.
Fang
Yin
Y
Department of Biomedical Engineering, The Cleveland Clinic Foundation, Cleveland, OH 44195, USA.
Yue
Guang H
GH
Hrovat
Kenneth
K
Sahgal
Vinod
V
Daly
Janis J
JJ
D000368:Aged; D001931:Brain Mapping; D003072:Cognition Disorders / Q000209:etiology*; D004550:Elbow / Q000294:innervation / Q000503:physiopathology*; D004569:Electroencephalography / Q000379:methods; D004576:Electromyography / Q000379:methods; D006801:Humans; D008875:Middle Aged; D009048:Motor Skills / Q000502:physiology*; D009068:Movement / Q000502:physiology*; D009716:Numerical Analysis, Computer-Assisted; D012782:Shoulder / Q000294:innervation / Q000503:physiopathology*; D020521:Stroke / Q000473:pathology / Q000503:physiopathology*; D017741:Survivors