A pilot study of changes in functional brain activity during a working memory task after mSMT treatment: The MEMREHAB trial

Abstract

Background: Working memory deficits are common in multiple sclerosis (MS). The modified Story Memory Technique (mSMT) has been shown to improve new learning and memory in MS, but its effects on working memory (WM) are currently unknown.

Objective: The present study presents a secondary analysis of data from a larger double-blind, placebo-controlled, randomized clinical trial and examines changes in cerebral activation on a WM task following mSMT treatment.

Methods: Sixteen participants with clinically definite MS were randomly assigned to treatment (n=7) or placebo-control groups (n=9) matched for gender, age and education. Baseline and immediate follow-up functional Magnetic Resonance Imaging (fMRI) was obtained for all subjects. During fMRI participants completed an N-back task, consisting of 0-, 1-and 2-back conditions.

Results: Significant increases in cerebral activation were noted in the dorsolateral prefrontal cortex, supplementary motor area and inferior parietal lobule at follow-up in the treatment group. No significant changes were noted in the placebo control group.

Conclusion: Due to the small sample size, results of the current study should be interpreted as preliminary. However, the observed pattern of activation of the frontoparietal network involved in WM found in the treatment group, suggests that mSMT training increases recruitment of attention- and WM-related neural networks. We conclude that mSMT treatment leads to changes in WM-related cerebral activation.

Keywords: Cognitive rehabilitation; Multiple Sclerosis; Working memory; fMRI; mSMT.