Cognitive improvement by non-pharmacological electrical stimulation modalities in mild cognitive impairment: a protocol for systematic review and network meta-analysis.

Objective: Mild cognitive impairment, characterized by progressive cognitive decline, represents a prevalent transitional state among the global aging population and demonstrates high conversion rates to Alzheimer's disease, establishing itself as a critical window for preventive interventions against AD. Although growing evidence supports the efficacy of various non-pharmacological therapies in enhancing cognitive function, their comparative effectiveness remains insufficiently elucidated. This study aims to analyze the efficacy and safety of different electrical stimulation modalities in treating MCI patients, quantitatively compare the therapeutic benefits across multiple interventions, and provide evidence-based recommendations to facilitate informed clinical decision-making. Methods: We will systematically search 13 databases. All relevant studies published from inception until November 1, 2025, will be retrieved. Two reviewers will independently assess the risk of bias for all included studies using the revised Cochrane Risk of Bias tool (RoB 2). The primary outcome will be the Montreal Cognitive Assessment score to evaluate changes in cognitive function. Secondary outcomes will include neuropsychological assessments related to cognition, such as the Mini-Mental State Examination (MMSE) and the Alzheimer's Disease Assessment Scale-Cognitive Subscale (ADAS-Cog), as well as the modified Barthel Index for activities of daily living and the patient-reported Pittsburgh Sleep Quality Index. Data synthesis will be performed using Stata software, employing a random-effects network meta-analysis model to compare the efficacy and safety of non-pharmacological electrical stimulation therapies. The surface under the cumulative ranking curve (SUCRA) will be used to estimate the probability of intervention hierarchies. The strength of evidence will be evaluated using the Grading of Recommendations, Assessment, Development, and Evaluations framework. Conclusion: This study will synthesize evidence from multiple studies on various electrical stimulation therapies for improving cognitive function in patients with mild cognitive impairment, thereby providing a diverse body of evidence to support clinical decision-making by physicians and optimization of treatment strategies for patients. Study Protocols Registration: [https://www.crd.york.ac.uk/prospero/], identifier [CRD420251184505].