Differential effects of 2 and 4 weeks repetitive transcranial magnetic stimulation inducing neuroplasticity on cognitive improvement

Background Repetitive transcranial magnetic stimulation (rTMS) is an efficient intervention for alleviating cognitive symptoms in Alzheimer's disease (AD), but the optimal treatment duration for high efficacy remains unclear. Objective This study investigates the effects of 2-week and 4-week rTMS on neural network plasticity and cognitive improvement, aiming to identify the optimal treatment duration for cognitive impairment. Methods rTMS was administered to cognitively impaired patients over 2-week and 4-week periods, exploring its effects on cognitive improvement and induced neural circuits. The study also examines the predictive value of these neural circuits for individual treatment responses. Results The 4-week rTMS treatment significantly outperformed the 2-week course in improving cognitive function. Neural activity analysis identified the precuneus as a key region for episodic memory. Changes in brain regions, particularly within the default mode network (DMN), visual network (VN), and motor network (MN), were associated with cognitive improvements. Baseline functional connectivity in these regions predicted changes in general cognition (r = 0.724, p < 0.001) and episodic memory (r = 0.447, p = 0.022) after rTMS. Conclusions Extended rTMS treatment enhances cognitive performance in cognitive impairment patients, with the 4-week course showing superior effects. Reduced connectivity in the DMN following rTMS was linked to cognitive improvements. The neural network baseline can predict patients’ treatment responses.