Impaired temporal context memory on anterograde but not retrograde tests in the absence of frontal pathology

This study examined the memory performance of patient RK who developed substantial memory impairments due to a hypothalamic glioma but in the absence of any evidence of frontal disturbance. RK was evaluated on both tests of anterograde and retrograde memory for temporal context. In the first experiment he exhibited marked deficits on a list discrimination task even when recognition performance was well within control range. Experiment 2 confirmed this disproportionate impairment of temporal order memory and showed that RK's list discrimination deficit was as severe as that found in alcoholic Wernicke-Korsakoff Syndrome patients. Experiment 3 showed that RK's temporal discrimination deficit was not a general deficit in discrimination because he performed normally on a spatial discrimination test of comparable difficulty to the temporal task. Experiment 4 examined RK's memory for deceased famous people and his ability to indicate the half decade in which they died. RK's performance was indistinguishable from controls whereas WKS patients were extremely impaired. This study adds to the view that frontal damage is not a necessary condition for impairment on anterograde measures of temporal context memory. However, further evidence from this study indicates that temporal judgments about pre-existing memories may depend on intact frontal lobe functioning.