Affiliations: Neuroscience Training Program, University of
Wisconsin-Madison, Madison, WI, USA | School of Medicine and Public Health, University of
Wisconsin-Madison, Madison, WI, USA | Emergency Medicine, Massachusetts General Hospital and
Brigham and Women's Hospital, MA, USA | Department of Radiology, University of
Wisconsin-Madison, Madison, WI, USA | Department of Neurology, Johns Hopkins University
School of Medicine, Baltimore, MA, USA
Note: [] Address for correspondence: Timothy B. Meier, University of
Wisconsin-Madison, Neuroscience Training Program, 1310d Wisconsin Institutes
for Medical Research, 1111 Highland Ave. Madison, WI 53705, USA. Tel.: +1 608
232 3343; Fax: +1 608 265 4152; E-mail: tbmeier@wisc.edu
Abstract: Functional imaging studies consistently find that older adults
recruit bilateral brain regions in cognitive tasks that are strongly
lateralized in younger adults, a characterization known as the Hemispheric
Asymmetry Reduction in Older Adults model. While functional imaging displays
what brain areas are active during tasks, it cannot demonstrate what brain
regions are necessary for task performance. We used behavioral data from acute
stroke patients to test the hypothesis that older adults need both hemispheres
for a verbal working memory task that is predominantly left-lateralized in
younger adults. Right-handed younger (age ⩽ 50,
n = 7) and older adults (age > 50,
n =21) with acute unilateral stroke, as well as younger
(n =6) and older (n =13) transient
ischemic attack (TIA) patients, performed a self-paced verbal item-recognition
task. Older patients with stroke to either hemisphere had a higher frequency of
deficits in the verbal working memory task compared to older TIA patients.
Additionally, the deficits in older stroke patients were mainly in retrieval
time while the deficits in younger stroke patients were mainly in accuracy.
These data suggest that bihemispheric activity is necessary for older adults to
successfully perform a verbal working memory task.
