Does repetitive transcranial magnetic stimulation improve cognitive function in age‐related neurodegenerative diseases? A systematic review and meta‐analysis

Objective: High-frequency, repetitive transcranial magnetic stimulation (rTMS) targeted over the dorsolateral prefrontal cortex (DLPFC) is widely used in research to promote neuroplasticity and cognitive enhancement. RTMS is a promising intervention to tackle cognitive decline in people with age-related neurodegenerative diseases. However, there is currently no systematic evidence examining the effects of DLPFC-targeted, high-frequency rTMS on cognitive function in this population. The aim of this systematic review was to evaluate the efficacy and moderators of this treatment intervention.

Methods: A comprehensive literature search of five electronic databases was performed to identify articles published before October, 2022. Following PRISMA guidelines, the identified articles were screened, data was extracted, and the methodological quality was assessed using the Cochrane tool, Risk of Bias 2. Meta-analyses were performed using R Studio (v.4.1.2).

Results: Sixteen studies involving 474 participants met the inclusion criteria, of which 8 studies measured global cognitive function. The results from the random-effects meta-analysis showed rTMS significantly improved global cognitive function relative to control groups shown by a large, significant effect size (g = 1.39, 95% CI, 0.34–2.43; p = 0.017). No significant effects were found between subgroups or for individual cognitive domains.

Conclusions: High-frequency rTMS, targeted over the DLPFC, appears to improve global cognitive function in people with age-related neurodegenerative diseases. However, these results should be interpreted with caution due to the small number of studies included, and high between-study heterogeneity.