Cognitive training interventions for dementia and mild cognitive impairment in Parkinson's disease.
Level 1 - systematic review of randomized trials
Cochrane systematic review and meta-analysis of randomised controlled trials
PubMed 32101639 · doi:10.1002/14651858.CD011961.pub2
What was done
The authors searched multiple databases through August 2019 to identify randomised controlled trials evaluating single- or multi-domain cognitive training interventions compared to control conditions in people with Parkinson's disease dementia (PDD) or Parkinson's disease mild cognitive impairment (PD-MCI). Methodological quality and certainty of evidence were assessed using Cochrane and GRADE tools.
What was found
Across seven trials with 225 participants assessing 4 to 8 weeks of cognitive training, there was no statistically significant effect on global cognition (6 trials, n = 178; standardised mean difference [SMD] 0.28, 95% CI -0.03 to 0.59), executive function (5 trials, n = 112; SMD 0.10, 95% CI -0.28 to 0.48), visual processing (3 trials, n = 64; SMD 0.30, 95% CI -0.21 to 0.81), activities of daily living (3 trials, n = 67; SMD 0.03, 95% CI -0.47 to 0.53), or quality of life (5 trials, n = 147; SMD -0.01, 95% CI -0.35 to 0.33). Small improvements were found for attention (5 trials, n = 160; SMD 0.36, 95% CI 0.03 to 0.68) and verbal memory (5 trials, n = 160; SMD 0.37, 95% CI 0.04 to 0.69), but these effects became uncertain in sensitivity analyses excluding a trial that enrolled cognitively intact participants.
Why it matters
Available evidence does not show that short-term cognitive training leads to meaningful cognitive or functional gains in Parkinson's disease-related cognitive impairment.
Limits
The total sample size was small (225 participants across seven trials), and the certainty of evidence for all outcomes was low due to risk of bias and imprecision. Only one trial evaluated PDD, two trials included participants without cognitive impairment, treatment durations were limited to 4 to 8 weeks, and adverse events were rarely reported.
Cited by
- supports Studies testing cognitive and mental exercises in patients who already have cognitive impairment generally show little clinical benefit.