Long-term effects of cognitive training in Parkinson's disease: A randomized, controlled trial

Background: Computerized cognitive training may be promising to improve cognitive impairment in Parkinson's disease and has even been suggested to delay cognitive decline. However, evidence to date is limited. The aim of this study was to assess the durability of eight-week cognitive training effects at up to two years follow-up. Methods: One hundred and thirty-six (136) individuals with Parkinson's disease, subjective cognitive complaints but without severe cognitive impairment (Montreal Cognitive Assessment >= 22) participated in this double-blind RCT. Participants underwent an eight-week home-based intervention of either adaptive, computerized cognitive training with BrainGymmer (n = 68) or an active control (n = 68). They underwent extensive neuropsychological assessment, psychiatric questionnaires and motor symptom assessment at baseline and one and two years after the intervention. We used mixed-model analyses to assess changes in cognitive function at follow-up and performed Fisher's exact tests to assess conversion of cognitive status.Results: There were no group differences on any neuropsychological assessment outcome at one- and two-year follow-up. Groups were equally likely to show conversion of cognitive status at follow-up. A considerable amount of assessments was missed (1y: n = 27; 2y: n = 33), most notably due to COVID-19 regulations.Conclusions: Eight-week cognitive training did not affect long-term cognitive function in Parkinson's disease. Future studies may focus on one cognitive subgroup to enhance reliability of study results. Intervention improvements are needed to work towards effective, lasting treatment options.