Variables Affecting Memory Deficits in Relapsing-Remitting Multiple Sclerosis

Memory impairment features prominently among the cognitive problems caused by Multiple Sclerosis (MS). In the present study 33 patients diagnosed with the relapsing-remitting form of MS and 30 controls matched on age, education, gender, and IQ were tested on measures of verbal learning (immediate and delayed recall of word lists and short stories), and lexical retrieval from long term memory (verbal fluency tests). MS patients demonstrated significant deficits in both immediate and delayed recall ability as well as in verbal fluency. Group differences in delayed verbal recall depended upon initial encoding ability of the same material, with the exception of delayed recall of the Wechsler Memory Scale Logical Memory story B. This finding may have been due to greater susceptibility of MS patients to the effects of proactive interference. Verbal fluency deficits appeared to depend upon a general impairment in the speed of information processing.