Interplay of physical and cognitive performance using hierarchical continuous-time dynamic modelling and a dual-task training regime in AD patients

BackgroundTraining studies typically investigate the cumulative rather than the analytically challenging immediate effect of exercise on cognitive outcomes. MethodsWe investigated the dynamic interplay between single-session exercise intensity and time-locked cognition in older adults with suspected Alzheimers dementia (N = 17) undergoing a 24-week dual-task regime. We specified a state of the art hierarchical Bayesian continuous- time dynamic model with fully connected state variables to analyze the bidirectional effects between physical and cognitive performance over time. ResultsHigher physical performance was dynamically linked to improved memory recognition (-1.335, SD = 0.201, 95 BCI [-1.725, -0.954]). The effect was short-term, lasting up to five days (-0.368, SD = 0.05, 95 BCI [-0.479, -0.266]). Clinical scores supported the validity of the model and observed temporal dynamics. ConclusionHigher physical performance predicted improved memory recognition in a day- by-day manner, providing a proof-of-concept for the feasibility of linking exercise training and cognition in patients with Alzheimers dementia. HighlightsO_LIHierarchical Bayesian continuous-time dynamic modelling approach C_LIO_LI72 repeated physical exercise (PP) and cognitive (COG) performance measurements C_LIO_LIPP is dynamically linked to session-to-session variability of COG C_LIO_LIHigher PP improved COG in subsequent sessions in subjects with Alzheimers dementia C_LIO_LIShort-term effect: lasting up to four days after training session C_LI Research in ContextO_LISystematic review: Training-induced effects on cognitive outcomes in Alzheimers dementia and/or associated dynamic Bayesian modelling approaches were reviewed. Although studies showed exercise-induced cognitive improvements or maintenance, most of these studies fail to capture the dynamic nature of the change and interplay of physical (PP) and cognitive (COG) performance. C_LIO_LIInterpretation: Using a sophisticated hierarchical Bayesian continuous-time dynamic modelling approach, a fully connected state variable model was specified. PP is dynamically linked to COG, i.e. higher PP predicted improved COG in subsequent sessions. This effect was rather short term, lasting for up to five days. C_LIO_LIFuture direction: Our results support exercise-induced effects on cognition. The cognitive system was still able to fluctuate and change favourably even in a sample with Alzheimers dementia. Further studies using dynamic modelling are necessary to replicate findings and examine other contributors to cognitive volatility in dementia. C_LI