The impact of Information processing speed on visuospatial memory encoding and retrieval in multiple sclerosis.

INTRODUCTION

Information processing speed (IPS) is frequently impaired in people with multiple sclerosis (PwMS) and can potentially interfere with functioning in other cognitive domains. A relationship between IPS and visuospatial memory has been shown, but the impact of IPS on the separate components of visuospatial memory remains unclear. In this study, we aim to investigate the association between IPS impairment and encoding, active and passive retrieval, and learning indices of visuospatial memory in PwMS.

METHODS

Cross-sectional data from 92 PwMS with cognitive complaints and 29 matched healthy controls (HCs) were retrospectively analyzed. IPS and visuospatial memory were measured using the Symbol Digit Modalities Test (SDMT) and the Brief Visuospatial Memory Test - Revised (BVMT-R), respectively. Hierarchical regression analyses were performed to assess the predictive value of IPS impairment (z-score ≤-1.5) for visuospatial encoding, active and passive retrieval, as well as learning indices scores.

RESULTS

In total, 47.8% of PwMS were impaired on the SDMT. IPS impairment significantly predicted lower performance on the second (ß = -0.26, p = 0.011) and third (ß = -0.29, p = 0.003) learning trials, active retrieval (ß = -0.33, p < 0.001), and learning index (ß = -0.28, p = 0.003) of the BVMT-R in PwMS. No significant association was found between IPS impairment and the initial learning and passive retrieval scores. In HCs, no association between IPS and BVMT-R performance was found.

CONCLUSION

PwMS with IPS impairment perform worse on visuospatial learning and memory, particularly in the later encoding phases and active retrieval of information. These findings highlight the importance of taking IPS impairment into account when interpreting visuospatial memory performance in MS.