The Effects of Computer-Based Cognitive Rehabilitation on Working Memory in Patients with Parkinson's Disease: A Systematic Review

Background: Deterioration of working memory(WM) is a common cognitive deficit in Parkinson's disease (PD), and severely influences the ability to lead an independent life. Interventions which can delay the impact of WM deficits could positively impact the independence and quality of life of patients. Objective: To evaluate effects of computer-based cognitive rehabilitation (CBCR) on WM in patients with PD. Methods: Pubmed, Embase, Psycinfo and Cochrane Library were systematically searched. Authors of included studies were contacted to detect unpublished data or articles not found by database-search. Broad selection criteria were applied because literature was expected to be limited. Studies were eligible for inclusion if they investigated the effects of CBCR on WM in a sample consisting of at least 50% PD patients, or in which the results of PD patients could be isolated. Studies were further eligible for inclusion in a planned meta-analysis if the effects of the CBCR intervention could be isolated, the CBCR intervention was compared to active or passive control groups consisting solely of PD patients, and the WM outcome measure could be isolated. Results: Only six studies were included despite broad inclusion criteria. Study results were heterogeneous, and the risk of bias in study methodology was either unclear or high. Two studies were eligible for meta-analysis. A meta-analysis was not performed, because these studies used different measures of WM which were not rated as equally valid and reliable. Conclusion: Existing literature is sparse and provides insufficient evidence to conclude if CBCR benefits WM in PD patients.