Patients with neurodegenerative diseases that cause mainly subcortical pathology often exhibit impairment when required to recall lists of unrelated words, but their memories are supposedly improved by test procedures that promote retrieval such as recognition or improve the organization of the to-be-remembered materials. Difficulties with floor effects on free recall and ceiling effects on recognition and other methodological concerns raise doubts about the validity of existing studies that tested these ideas. Using the verbal memory subtests of the RBANS, we [Arch. Clin. Neuropsychol. 18 (2003) 509] expressed each patient’s performances on Story Memory, List Learning, Story Recall, List Recall, and List Recognition as Z scores relative to his or her age group. Then, the Z scores were subtracted pairwise to test hypotheses about the nature of memory in Parkinson’s disease (PD). Contrary to expectation, patients with PD did not show better immediate or delayed recall of stories relative to lists and they did not show better recognition than recall.
In the present investigation, the same methodology was used to study verbal memory in multiple sclerosis, a disease that primarily affects subcortical structures. In contrast to previous results for patients with PD, the patients with MS exhibited better recall of stories than of lists and better List Recognition than Recall. Differences in the pathology of entorhinal regions in PD and MS may contribute to the differing patterns of memory impairment of these patients. The results emphasize that most patients with MS with memory impairments have deficits that are relatively mild and potentially remediable.