Efficacy of non-invasive neuromodulation technologies in improving cognitive function and activities of daily living in patients with Alzheimer’s disease, Parkinson’s disease, and stroke: a systematic review and network meta-analysis

BACKGROUND: In recent years, non-invasive neuromodulation techniques (NINM) have demonstrated potential in promoting cognitive recovery. However, their relative efficacy across various disease contexts and stimulation protocols remains unclear. OBJECTIVE: To evaluate the efficacy and ranking of non-invasive neuromodulation techniques in improving cognitive function and activities of daily living (ADLs) among patients with Alzheimer’s Disease, Parkinson’s Disease, and Stroke, and to explore the impact of age on therapeutic outcomes in order to provide evidence-based guidance for personalized clinical interventions. METHODS: We conducted a systematic literature search of PubMed, Web of Science, the Cochrane Library, Scopus, and EMBASE databases without any language restrictions. The search was limited to the period from the inception of each database up to May 2025. Inclusion criteria were Randomized Controlled Trials (RCTs) involving patients (≥ 18 years) with patients with Alzheimer’s Disease, Parkinson’s Disease, and Stroke and cognitive impairment. Interventions included Repetitive Transcranial Magnetic Stimulation (rTMS), intermittent Theta Burst Stimulation (iTBS), Transcranial Direct Current Stimulation (tDCS), or sham. Outcomes included Montreal Cognitive Assessment (MoCA), Mini-Mental State Examination (MMSE), Modified Barthel Index (MBI), and Instrumental Activities of Daily Living (IADL). Data extraction and risk of bias followed Cochrane guidelines. A Bayesian network meta-analysis was performed in R, with effects ranked by Surface Under the Cumulative Ranking curve (SUCRA). RESULTS: A total of 41 RCTs with 1957 participants were included. For cognitive outcomes, iTBS showed potential advantages on MoCA (MD = 3.62, 95% CI = 2.10 to 5.15; SUCRA = 95.1%) and MMSE (MD = 3.84, 95% CI = 1.96 to 5.71; SUCRA = 92.4%). Subgroup analyses revealed the strongest effects with stimulation of frontoparietal cognitive network. Age was identified as a factor influencing outcomes. For functional outcomes, low-frequency rTMS most improved MBI (MD = 13.43, 95% CI = 10.27 to 16.59; SUCRA = 85.8%), and tDCS had the greatest effect on IADL (SUCRA = 75.4%). CONCLUSION: Non-invasive neuromodulation techniques improve cognitive function and ADLs in patients with Alzheimer’s Disease, Parkinson’s Disease, and Stroke, with iTBS showing significant cognitive benefits. Due to research heterogeneity and methodological limitations, large-scale standardized RCTs are needed to optimize protocols, explore age- and disease-specific effects, and enhance clinical translation.