Memory impairment in multiple sclerosis.

The memory performance of 22 Multiple Sclerosis (MS) subjects and their matched controls was compared on three tasks: a perceptual memory test, a picture recognition test and a verbal recognition test. Results showed that perceptual memory does not suffer as a consequence of MS. Moreover, MS subjects are as sensitive as controls to deep semantic encoding of individual items in a picture recognition task. However, for a verbal recognition task, where a semantic encoding strategy was optional, MS subjects were less likely to report use of a strategy. Those MS subjects who did use a strategy, did more poorly on memory for verbal information than controls. The results suggest a specific inter-item semantic encoding problem in MS.