Validity of the California Verbal Learning Test–II in Multiple Sclerosis

Abstract

Multiple sclerosis (MS) is a disease of the central nervous system where roughly 50% of patients exhibit cognitive impairment. Episodic memory defects are particularly common in MS and the California Verbal Learning Test: 2nd Edition (CVLT-II) was recommended for assessment in MS in a recently published consensus position paper. We investigated the validity of the CVLT-II in 351 MS patients and 69 demographically matched normal controls. MS patients performed significantly more poorly on 18 of the 23 measures examined. In addition to a general memory factor, factor analysis revealed five distinct factors conforming to measures of consolidation, primary/recency effect, proactive interference, and learning asymptote. The external validity of the CVLT-II was also supported by logistic regression analysis, which separated employed from work-disabled MS patients. We conclude that the CVLT-II is a valid test in MS and provides a rich constellation of verbal memory measures.

Cognitive Deficits and Neuropsychological Assessment in Multiple Sclerosis

“…Patients with MS often have difficulties with memory-the prevalence is reported between 40 and 65%. The most common verbal memory tests are tasks in which the patient learns a wordlist [16]. Visuospatial memory, too, is affected in patients with MS [13].…”

Abnormal Long-Term Episodic Memory Profiles in Multiple Sclerosis?

“…In previous group studies, executive memory difficulties in MS have been widely reported [8,[26][27][28] and have generally been described as encoding impairments [8,23]. Some authors are operationalized this deficit as a pathological score for both cued recalls and delayed recognition [28,26], although a storage deficit could also explain this long-term profile.…”

“…However, for all these scores, data reported in the literature are controversial. Discrepancies between studies cannot be explained in terms of sample sizes, since conflicting results have been reported both in relation to small (n<30 MS patients [28]; Randolph et al, 2005 [36] for examples) and large study samples (n>200, [8,37]). For similar disease durations (11.5 years), differences in the EDSS score may influence performances, but only when disability increases (no significant difference below and above 1.5 [25]; selective deficit for 4.7 group versus 2.8, [26]).…”

“…When considering episodic memory abilities, it is usual to dissociate, on the one end, the long-term maintenance of information over the period of a few minutes to a lifetime (storage). On the other hand, the manipulation of information, which may include multiple executive sub-processes such as encoding, retrieval, sensitivity to interference and learning strategy [7][8][9].While executive impairments can be targeted by cognitive intervention, storage deficits are more likely to require prosthetic strategies (agenda or other external help).…”

“…Among the most comprehensive studies [7,8,21,[23][24][25][26]28], only Diamond and colleagues [21] and Stegen and colleagues [8] exhaustively reported on raw scores. In a large sample (351 patients), the latter study reported impaired performances for all the described indices.…”