Improved cognitive performance and event-related potential changes following working memory training in patients with multiple sclerosis

BACKGROUND: Few studies of cognitive rehabilitation in multiple sclerosis (MS) have targeted working memory specifically. OBJECTIVE: We examined the effects of n-back working memory training on cognitive performance and brain function in patients with MS. METHODS: Patients with MS (n = 12) and healthy controls (HC; n = 12) underwent 20 sessions of n-back working memory training. Before and after training (pre- and posttest) cognitive event-related potential (ERP) measures were obtained during a 3-back task. In addition, a battery of cognitive tests was administered. RESULTS: Following n-back training, both MS patients and HCs showed significant improvement on tests of working memory, processing speed, complex attention, and reasoning ability. MS and HCs also exhibited an enhancement of N2 ERP component amplitude, and earlier N2 and P3 latencies, following n-back training. CONCLUSIONS: Targeted training of working memory with the n-back task may improve cognitive function in MS. Enhancement of N2 ERP component amplitude and shorter N2 and P3 latency following training in patients with MS is consistent with plasticity of neural processes that are involved in working memory.