Comparing the effects of cognitive and physical training on cognitive function and brain activation in people with mild cognitive impairment and mild dementia: a randomized controlled trial.

OBJECTIVE: Cognitive and physical training are frequently used interventions in individuals with early cognitive impairment. This study compared the effects of different training strategies in individuals with mild cognitive impairment (MCI) and mild dementia (MD). DESIGN: Randomized controlled trial. SETTING: University laboratory. PARTICIPANTS: Older adults aged over 65 years with a diagnosis of MCI or MD were eligible. INTERVENTIONS: Sixty participants were randomly assigned to cognitive training group (CTG), physical training group (PTG), and control group (CG), with 20 participants in each group. CTG and PTG received interventions for 30 minutes/session, 3 sessions/week, for 8 weeks. CG received health education. MAIN OUTCOMES MEASURES: Primary outcomes were cognition and prefrontal cortex (PFC) activation during a cognitive task. Global cognition was measured by the Alzheimer's disease assessment scale-cognitive subscale (ADAS-cog), executive function by the frontal assessment battery (FAB) and trail making test-B (TMT-B), attention by the trail making test-A (TMT-A), and memory by the category fluency test (CFT). PFC activation was documented with functional near-infrared spectroscopy. Secondary outcomes included the timed up and go (TUG) test and the modified falls efficacy scale (MFES). Data were analyzed using generalized estimating equations (GEE). RESULTS: CTG significantly improved ADAS-cog (p=0.022), FAB (p<0.001), TMT-A (p=0.014), TMT-B (p=0.008), and CFT (p=0.004) than CG. PTG significantly improved ADAS-cog (p=0.008), TMT-B (p=0.033), and CFT (p=0.005) compared with CG. CTG exhibited significantly decreased PFC activation compared to CG and PTG (p=0.002 vs. physical training, p=0.015 vs. control). PTG significantly improved TUG performance compared to CG and CTG (p=0.046 vs. cognitive training, p=0.003 vs. control). CONCLUSIONS: Both training strategies showed potential cognitive benefits, with only PTG exceeding the minimal clinically important difference on the ADAS-Cog. Reduced PFC activation in the CTG may reflect improved neural efficiency; however, this interpretation requires further verification.