Neurophysiological biomarkers using transcranial magnetic stimulation in Alzheimer’s disease and mild cognitive impairment: A systematic review and meta-analysis

Transcranial magnetic stimulation (TMS) is a non-invasive neurophysiological tool that enables the investigation of cortical excitability in human brain. Paired-pulse TMS paradigms include short- and long-interval intracortical inhibition (SICI/LICI), facilitation (ICF), short-latency afferent (SAI), which can assess functions GABAergic, glutamatergic, cholinergic neural circuits, respectively. We conducted first systematic review meta-analysis to compare these indices among patients with AD, mild cognitive impairment (MCI), healthy controls (HC). Our meta-analyses indicated RMT, SAI, SICI, LICI were significantly lower while ICF did not show difference AD compared HC. In MCI, RMT SAI than conclusion, motor was increased, function decreased MCI comparison HC had GABAergic glutamatergic results warrant further studies differentiate HC, employing multimodal neurophysiology.