Effect of Eight-Week Online Cognitive Training in Parkinson’s Disease: A Randomized Controlled Trial

Abstract

Background: Cognitive training (CT) has been proposed as a non-pharmacological treatment option for the frequent cognitive impairments occurring in Parkinson's disease (PD). Objective: Assess the efficacy of CT on cognitive function in PD. Methods: In this double-blind, randomized controlled trial we enrolled 140 PD patients with significant subjective cognitive complaints. In eight weeks, participants underwent 24 sessions of computerized multi-domain CT or an active control condition for 45 minutes each (n=70 vs. n=70). The primary outcome was the accuracy on a computerized Tower of London task; secondary outcomes included effects on other neuropsychological outcomes and subjective cognitive complaints. Outcomes were assessed before and after training and at six-months follow-up, and were analyzed with multivariate mixed-model analyses. Results: The intention-to-treat population consisted of 136 participants. Multivariate mixed-model analyses showed no group difference on the Tower of London accuracy corrected for baseline performance: B: -0.06, 95% CI: -0.27 to 0.15, p=0.562. Participants in the CT group were on average 0.30 SD (i.e., 1.5 seconds) faster on the Tower of London, difficulty load 4 (secondary outcome): 95% CI: -0.55 to -0.06, p=0.015. CT had similar positive effects on other processing speed-related executive function tasks, although these did not reach statistical significance. At follow-up, no group differences were present. Conclusions: The results show tentative but consistent positive effects of CT on processing speed during executive functioning. Future studies should investigate booster sessions to increase durability, optimize training duration, and study different sub-groups of PD patients along the continuum of cognitive decline towards PD dementia.

Cognitive Training in Parkinson's Disease Induces Local, Not Global, Changes in White Matter Microstructure

“…Our results also showed that the reduction in FA in the ATR in the cognitive training group was associated with faster responses on the ToL task. Although this subsample of PD patients with a DWI scan did not show significant training-related increases in cognitive performance on the group level, our analyses in the entire sample of 140 PD patients showed positive effects of cognitive training on ToL response time, especially for the more cognitively demanding task load 4 [34]. Combining these results they suggest training-induced improvement in processing speed during executive functioning that is accompanied with an increase in intra-striatal or thalamo-striatal fibers on the individual level.…”

“…Interestingly, the decrease in FA in the ATR was associated with faster responses on ToL task (although this fell just short of our multiple comparison threshold). Traininginduced faster responses on the ToL task were the main finding on the behavioral level of our randomized controlled trial [34]. Cognitive training had no effect on network topology on neither the global or subnetwork level.…”

“…Supplementary Table 1 shows the effects of the intervention on performance on the ToL and SCWT in this subsample of 79 PD patients. Compared with the full sample of PD patients (see [34]), we observed similar but not statistically significant effect sizes, likely due to the decrease in power. 2).…”

Cognitive training in Parkinson’s disease induces local, not global, changes in white matter microstructure

“…Our results also showed that the reduction in FA in the ATR in the CT group was associated with faster responses on the ToL task. Although this subsample of PD patients with a DWI scan did not show significant differences in cognitive performance after training on the group level, our analyses in the entire sample of 140 PD patients showed positive effects of CT on ToL reaction time, especially for the more cognitively demanding task load 4 [34]. Combined these results are suggestive of training-induced improvement in processing speed during executive functioning that is accompanied with an increase in intra-striatal or thalamo-striatal fibers on the individual level.…”

“…Interestingly, the decrease in FA in the ATR was associated with faster responses on ToL task (although this fell just short of our multiple comparison threshold). Training-induced faster responses on the ToL task were the main finding on the behavioral level of our randomized controlled trial [34]. CT had no effect on network topology on neither the global or subnetwork level.…”