Computerised cognitive training combined with nutritional counseling in mild cognitive impairment - results of a 2 × 2 factorial randomized controlled trial (BrainFit-nutrition study)

Background Computerized cognitive training (CCT) and nutritional interventions may improve cognitive functioning in individuals with mild cognitive impairment (MCI). This study investigated whether a combination of CCT and online nutritional counseling can improve global cognition in individuals with MCI. We also evaluated differences between MCI-specified and active control versions of the interventions. Methods In this 2 × 2 factorial randomized controlled trial (BrainFit-Nutrition study), conducted fully remotely, participants in Germany with a psychometric diagnosis of MCI (age 60+) were randomized into four groups (Intention to treat, n = 270). For each intervention, one MCI specified and one active control version were developed (cognition: individualized CCT (iCCT) vs. basic CCT (bCCT); nutrition: whole-food plant-based nutrition (WFPB) vs. German Nutrition Society (DGE)). At baseline and after six months, cognitive functioning was assessed with the Montreal Cognitive Assessment (MoCA; primary outcome: change after six months). A mixed-model ANCOVA (t0-t6, complete case strategy (CC), n = 228) was applied for the main analysis. Results All four groups achieved a significant improvement of approximately 2 points on the MoCA after six months. Estimated marginal means varied from M = 2.44 (iCCTxDGE) to M = 1.77 (iCCTxWFPB), notably without significant group differences. The 2 × 2 mixed ANCOVA revealed a significant main effect of time ( F = 3.96, p = 0.048, partial η 2 = 0.018). The specific content of the respective modalities being compared (iCCT vs. bCCT; WFPB vs. DGE-oriented counseling) did not appear to make a relevant group difference with regard to the primary outcome. After 6 months, 55% of all participants reached non-MCI values on the MoCA. Conclusion The results of this study suggest, that in people with MCI, notable improvement in global cognition can be achieved in a six-months intervention period. When CCT is combined with digital nutritional counseling, the form of intervention – whether elaborate or basic – apparently did not modify the outcome; rather, this data set suggests that it is worthwhile to proactively undertake something in both domains. Future clinical studies in mixed-methods-designs, including usual-care comparators, basic science study modules, qualitative aspects and health economic variables are warranted to gain a better understanding of mechanisms, sustainability of effects, clinical relevance, and cost-effectiveness. Trial registration ISRCTN10560738; registered 11/23/2021.