A meta-analysis of the effects of aging on motor cortex neurophysiology assessed by transcranial magnetic stimulation.

ABSTRACT: OBJECTIVE:Transcranial magnetic stimulation (TMS) is a non-invasive tool used for studying cortical excitability and plasticity in the human brain. This review aims to quantitatively synthesize the literature on age-related differences in cortical excitability and plasticity, examined by TMS. METHODS:A literature search was conducted using MEDLINE, Embase, and PsycINFO from 1980 to December 2015. We extracted studies with healthy old (50-89years) versus young (16-49years) individuals that utilized the following TMS measures: resting motor threshold (RMT), short-interval cortical inhibition (SICI), short-latency afferent inhibition (SAI), cortical silent period (CSP), intracortical facilitation (ICF), and paired associative stimulation (PAS). RESULTS:We found a significant increase in RMT (g=0.414, 95% confidence interval (CI) [0.284, 0.544], p<0.001), a significant decrease in SAI (g=0.778, 95% CI [0.478, 1.078], p<0.001), and a trending decrease in LTP-like plasticity (g=-0.528, 95% CI [-1.157, 0.100] p<0.1) with age. CONCLUSIONS:Our findings suggest an age-dependent reduction in cortical excitability and sensorimotor integration within the human motor cortex. SIGNIFICANCE:Alterations in the ability to regulate cortical excitability, sensorimotor integration and plasticity may underlie several age-related motor deficits.

SUBMITTER: Bhandari A 

PROVIDER: S-EPMC4956500 | biostudies-literature | 2016 Aug

REPOSITORIES: biostudies-literature