Scoping Review Methodology

A scoping review was chosen over a systematic review because the research questions are broad and exploratory rather than narrowly confirmatory. No formal quality appraisal of individual studies will be conducted, which is consistent with scoping review methodology. The review will use narrative synthesis rather than meta-analysis because the included studies are expected to be heterogeneous. The review distinguishes methodologies from methods because the terms are often conflated in the literature. A scoping review is more appropriate than a systematic review because the existing literature is limited, conceptually inconsistent, and dominated by descriptive reports lacking rigorous evaluative designs. This scoping review will be the first systematic mapping of evidence on the oral microbiome's relationship to frailty, sarcopenia, and neurocognitive disorders considered together. The review is presented as the first to systematically map direct and indirect costs of PPI in stroke research, including under-reported areas such as emotional labour and governance. The review does not assess risk of bias or quality of evidence, consistent with scoping review conventions. Studies are no…