NEUROPSYCHOLOGICAL DEFICITS ARE CORRELATED WITH FRONTAL HYPOMETABOLISM IN POSITRON EMISSION TOMOGRAPHY STUDIES OF OLDER ALCOHOLIC PATIENTS

In an extension of previous work, we studied the behavioral correlates of medial frontal lobe glucose hypometabolism in chronically alcohol- dependent patients. Thirty-one male patients who were detoxified, medi cally stable, and free of other central nervous system risk factors fo r neuropsychological impairment were examined with (1) anatomic imagin g (CT or MR), (2) functional imaging with [F-18] fluorodeoxyglucose (F -18-FDG) and positron emission tomography (PET), and (3) a battery of neuropsychological tests, including two measures of abstraction known to be generally sensitive to frontal lobe disease or dysfunction [the Wisconsin Card Sorting Test (WCST) and the Halstead Category Test (HCT )]. F-18-FDG PET data from 18 age- and sex-matched normal control subj ects were used for comparison. All patients met criteria for severe al cohol dependence and for at least a mild degree of alcoholic-induced c ognitive impairment. Although the mean IQ level of the alcoholic patie nts was in the average range, the concepts attained and the error scor es on the WCST and HCT were significantly impaired in comparison with established norms. Local cerebral metabolic rate for glucose (LCMRglc) was significantly decreased in a sagittal strip of the medial frontal cortex in the alcoholic patients as compared with the normal controls . Comparison of data from PET scans and anatomic images indicated that the reduced LCMRglc could not be attributed to reduced amounts of tis sue alone. A statistically significant relationship was found between LCMRglc in the medial frontal region of the cerebral cortex and perfor mance on the WCST, but not the HCT. These findings suggest that chroni c alcohol intake results in impaired function of cerebral tissue in th e medial frontal region. The impairment pertains both to tissue metabo lic rates and the behavioral correlates of these rates.