Implicit memory in multiple sclerosis

A number of neuropsychological studies have revealed that memory problems are relatively common in patients with multiple sclerosis (MS). It may be useful to compare MS with conditions such as Huntington's disease (HD), which have been referred to as subcortical dementia. A characteristic of these conditions may be an impairment in implicit (unconscious) memory, but not in explicit (conscious) memory. The present study examined the functioning of explicit and implicit memory in MS. Results showed that implicit memory was not significantly impaired in the MS subjects, and that they were impaired on recall but not recognition. A correlation was found between implicit memory performance and disability status in MS patients. Findings also suggest the possibility of long-term priming of implicit memory in the control subjects. The implications of these results are discussed.