Cerebral glucose metabolism as a predictor of recovery from aphasia in ischemic stroke.
OBJECTIVE
The recovery of language function seen in poststroke aphasia is significantly related to the severity of the initial neurologic deficit. However, a great deal of variability still remains in the improvement that is actually achieved. To detect predictors that will help in explaining this variability, positron emission tomography (PET) and fluorodeoxyglucose F 18 (18-F-fluorodeoxyglucose) were used and the results were analyzed by stepwise regression.


METHODS
Using PET imaging after injection of fluorodeoxyglucose F 18, the regional changes in glucose metabolism in 26 patients at a period of 12 to 18 days following an ischemic stroke involving the left middle cerebral artery were examined. A second PET examination was performed on 17 of our 26 patients who were able to perform speech activation exercises. All patients received an initial and a 4-month follow-up evaluation of language performance.


METHODS
During the two PET studies and the first language assessment, the patients were hospitalized in a neurologic clinic. The follow-up evaluation of language performance was performed when the patients were ambulatory.


METHODS
Twenty-six patients (10 women, 16 men; aged 38 to 77 years; mean +/- SD, 60 +/- 9.2 years) were selected in the study. Their aphasias were of various types and of varying severity ranging from mild impairment to severe global aphasia.


METHODS
For the stepwise regression analysis of variables, the following variables were analyzed in resting and activation PET to explain residual variance from the first to the second Token Test: regional cerebral metabolic rate for glucose of infarct and mirror region, left and right cerebral and cerebellar hemispheres, left and right Broca's area, left and right Wernicke's area, and left and right temporoparietal cortex.


RESULTS
As was expected, early and late Token Tests exhibit a high correlation (.85). The stepwise regression analysis shows that only the left cerebral hemisphere glucose value of the resting PET had significant effect on the residual variance of the Token Test regression. Regional metabolic rates during speech activation had the largest contribution to a significant recovery from aphasia. The infarct area and its corresponding mirror region, the left Broca's area, and the entire left cerebral hemisphere accounted for 80% of the residual variance.


CONCLUSIONS
These results emphasize not only the application of PET activation studies in the prediction of a tissue's potential reserve capacity but also the importance of left hemisphere integrity in the recovery of functional language.
Heiss
W D
WD
Max-Planck-Institut für Neurologische Forschung and Neurologische Universitätsklinik Köln, Germany.
Kessler
J
J
Karbe
H
H
Fink
G R
GR
Pawlik
G
G
D000328:Adult; D000368:Aged; D001037:Aphasia / Q000453:epidemiology / Q000209:etiology* / Q000503:physiopathology; D001921:Brain / Q000000981:diagnostic imaging / Q000378:metabolism*; D002561:Cerebrovascular Disorders / Q000000981:diagnostic imaging / Q000209:etiology / Q000503:physiopathology*; D005260:Female; D005947:Glucose / Q000378:metabolism*; D006801:Humans; D002546:Ischemic Attack, Transient / Q000150:complications / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests / Q000706:statistics & numerical data; D011237:Predictive Value of Tests; D012044:Regression Analysis; D014055:Tomography, Emission-Computed
D005947:Glucose