Task switching after stroke.
OBJECTIVE
Task switching is a cognitive skill that may be compromised after brain damage. The purposes of this study were to examine task-switching abilities in the subacute phase after stroke, to determine whether a switching task under endogenous or internal control is more difficult than a switching task under exogenous or cued control, and to determine whether deficits in switching attenuate in the first few months after stroke.


METHODS
The participants in this study were 46 adults with stroke and 38 adults without stroke.


METHODS
Subjects performed 2 computer-based switching tasks, an alternating task that relied on endogenous control and a cued task that relied on exogenous control. Testing was done in subjects' homes at 1 and 3 months after stroke and at a 2-month interval for control subjects. Switch costs, or the difference between the no-switch condition and the switch condition, were calculated for accuracy and response time.


RESULTS
Subjects in the stroke group had higher switch costs for accuracy than did subjects in the control group. The alternating task was more difficult than the cued task, with higher switch costs for accuracy and response time. The alternating task was particularly difficult for subjects in the stroke group, with high switch costs for accuracy. Both groups showed decreased response time switch costs at the second testing session.


CONCLUSIONS
Task switching, particularly if under endogenous control, is impaired in adults in the subacute phase after stroke. Clinicians should be aware of performance deficits that may relate to task switching.
Pohl
Patricia S
PS
Department of Physical Therapy & Rehabilitation Sciences, University of Kansas Medical Center, Kansas City, KS 66160, USA. ppohl@kumc.edu
McDowd
Joan M
JM
Filion
Diane
D
Richards
Lorie G
LG
Stiers
William
W
Kluding
Patricia
P
D000368:Aged; D016022:Case-Control Studies; D003072:Cognition Disorders / Q000175:diagnosis / Q000209:etiology*; D003201:Computers; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012720:Severity of Illness Index; D020521:Stroke / Q000145:classification / Q000150:complications*; D013647:Task Performance and Analysis; D013997:Time Factors