Effectiveness of multidomain versus single-domain non-pharmacological interventions for cognitive decline in mild cognitive impairment and dementia: a systematic review protocol

OBJECTIVE: This review will assess whether multidomain non-pharmacological interventions are more effective than single-domain strategies in mitigating cognitive decline for people with mild cognitive impairment (MCI) and dementia. INTRODUCTION: MCI and dementia are suboptimal conditions that significantly reduce quality of life for affected individuals and their families. Non-pharmacological, lifestyle-based interventions have shown promise in attenuating cognitive decline in these populations by targeting modifiable risk factors associated with cognitive performance. However, it remains unclear whether multidomain interventions that simultaneously address numerous risk factors are more effective than single-domain approaches in these individuals. ELIGIBILITY CRITERIA: Experimental and quasi-experimental studies evaluating the effects of non-pharmacological multidomain versus single-domain interventions on cognitive test performance in adults diagnosed with MCI or dementia will be included. METHODS: This review will be conducted according to the JBI methodology for reviews of effectiveness. The databases to be searched include PubMed, CINAHL, Embase, PsycINFO, Web of Science, Scopus, and the Cochrane Central Register of Controlled Trials, as well as multiple sources of unpublished evidence and gray literature. Two reviewers will independently perform study selection, and screen titles, abstracts, and full-text records that meet the eligibility criteria. Assessment of studies' methodological quality using JBI critical appraisal tools and AI-assisted data extraction will be completed by 2 reviewers independently. Where appropriate, meta-analyses will be performed per cognitive domain and population group. Certainty of findings will be determined by following the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) approach. REGISTRATION NUMBER: PROSPERO CRD420261398271.