Effects of different non-invasive brain stimulation interventions on cognitive and functional abilities in people with mild cognitive impairment and dementia: a systematic review and meta-analysis.

BACKGROUND

Non-Invasive Brain Stimulation (NIBS) shows promise for enhancing cognitive and functional abilities in people with cognitive impairment. However, its independent effects remain unclear due to the mixing of standalone and combination treatments in previous reviews.

OBJECTIVE

To evaluates the short-term and sustained effects of NIBS on cognitive and functional abilities and identify optimal stimulation parameters in people with cognitive impairment.

METHODS

Randomized controlled trials that compared NIBS interventions with sham/control interventions for people with cognitive impairment were searched across eight databases from inception to November 2, 2024. Methodological quality, risk of bias, and certainty of evidence were assessed using the PEDro scale, ROB 2.0 tool, and GRADE framework.

RESULTS

Eighty studies involving 3177 participants were reviewed. The results showed that traditional repetitive transcranial magnetic stimulation had short-term positive effects on global cognitive function (Hedges'g: 0.40), verbal episodic memory (0.53), and attention (0.51) and had both short-term (0.40) and sustained effects (0.57) on activities of daily living. Intermittent theta-burst stimulation improved verbal episodic memory (0.55), working memory (1.17), verbal fluency (0.49), naming ability (0.75), and visuospatial ability (0.97). Transcranial direct current stimulation afforded short-term improvements in global cognitive function (0.82), working memory (0.58), verbal fluency (0.83), naming ability (0.31) and attention (0.82) and sustained improvements in cognitive flexibility (4.28), inhibitory control (2.43), attention (1.62), and visuospatial ability (5.60).

CONCLUSIONS

NIBS offers significant cognitive and functional benefits for people with cognitive impairment, with effects varying by stimulation type and parameters.