STOCKHOLM – Cognitive rehabilitation to address memory deficits in multiple sclerosis (MS) can take a page from efforts to help those with other conditions, but practitioners and patients should realize that more intensive interventions are likely to be of greater benefit in MS.
in addressing the memory problems frequently seen in MS, reported at the annual congress of the European Committee for Treatment and Research in Multiple Sclerosis.
Hippocampal pathology can underlie the high-impact memory deficits that are seen frequently in patients with MS, noted Mr. Bouman, a doctoral student at Amsterdam University Medical Centers, and his collaborators. However, they observed, which strategies might best ameliorate hippocampal memory loss for those with MS is an open question.
To address this knowledge gap, Mr. Bouman and his coauthors conducted a systematic review and meta-analysis that aimed to determine which memory interventions in current use most help hippocampal memory functioning. The authors did not limit the review to MS, but included other conditions where hippocampal lesions, atrophy, or changes in connection or functioning may affect memory. These include healthy aging, mild cognitive impairment, and Alzheimer’s disease.
Included in the search for studies were those that used either cognitive or exercise interventions and also evaluated both visuospatial and verbal memory using validated measures, such as the Brief Visuospatial Memory Test or the California Verbal Learning Test.
After reviewing an initial 6,697 articles, the authors used Cochrane criteria to eliminate studies that were at high risk of bias. In the end, 141 studies were selected for the final review, and 82 of these were included in the meta-analysis. Eighteen studies involving 895 individuals addressed healthy aging; 39 studies enrolled 2,256 patients with mild cognitive impairment; 8 studies enrolled 223 patients with Alzheimer’s disease; and 26 studies involving 1,174 patients looked at cognitive impairment in the MS population.
To express the efficacy of the interventions across the various studies, Mr. Bouman and collaborators used the ratio of the difference in mean outcomes between groups and the standard deviation in outcome among participants. This ratio, commonly used to harmonize data in meta-analyses, is termed standardized mean difference.
Individuals representing the healthy aging population saw the most benefit from interventions to address memory loss, with a standardized mean difference of 0.48. Patients with mild cognitive impairment saw a standardized mean difference of 0.46, followed by patients with Alzheimer’s disease with a standardized mean difference of 0.43. Patients with MS lagged far behind in their response to interventions to improve memory, with a standardized mean difference of 0.34.
Looking at the different kinds of interventions, exercise interventions showed moderate effectiveness, with a standardized mean difference of 0.46. By contrast, high intensity cognitive training working on memory strategies was the most effective intervention, said Mr. Bouman and his coauthors: This intervention showed a standardized mean difference of 1.03.
Among the varying conditions associated with hippocampal memory loss, MS-related memory problems saw the least response to intervention, “which might be a result of a more widespread pattern of cognitive decline in MS,” noted Mr. Bouman and coauthors.
“Future studies should work from the realization that memory rehabilitation in MS might require a different approach” than that used in healthy aging, mild cognitive impairment, and Alzheimer’s disease, wrote the authors.
Their review revealed “persistent methodological flaws” in the literature, they noted. These included small sample sizes and selection bias.
Mr. Bouman reported that he had no disclosures. One coauthor reported financial relationships with Sanofi Genzyme, Merck-Serono and Biogen Idec. Another reported financial relationships with Merck-Serono, Bogen, Novartis, Genzyme, and Teva Pharmaceuticals.
SOURCE: Bouman P et al. ECTRIMS 2019. Abstract .