A COMPARISON OF AGE-RELATED DEFICITS IN MEMORY AND FRONTAL-LOBE FUNCTION FOLLOWING ORAL LORAZEPAM ADMINISTRATION

Differential responses on cognitive function of young (18-45 years, n= 17) and elderly (60-75 years, n=9) subjects were compared before and a fter a challenge with lorazepam (2 mg oral) or placebo. Tests of memor y and frontal lobe function were administered to determine the specifi city of the amnesic deficit produced and the interaction of drug and t he aging brain. Anterograde amnesia, as assessed by recall of a word l ist, was noted in both groups and was greater in the elderly. Whereas lorazepam produced only impaired recall in the young group, the elderl y group manifested a further range of cognitive impairments, including decreased verbal fluency on the controlled oral word association test and reduced performance on the Wisconsin card-sorting test. These imp airments in the elderly group could not be attributed to performance d eficits pre-drug. Short-term memory, as evidenced by digit span and th e copy trial of the Rey figure, was not impaired by lorazepam. It is c oncluded that whilst lorazepam produces a relatively 'pure' amnesia in young to middle aged adults, in the elderly there is an admixture of deficits in some frontal lobe functions. This is presumed to reflect a ge-related changes in the brain and may be analogous to the spectrum o f results noted in Korsakoff's psychosis as opposed to 'pure' dienceph alic amnesia.