Citation

Tremblay S, de Beaumont L, Lassonde M, Théoret H. J. Neurotrauma 2011; 28(4): 493-502.

Affiliation

University of Montreal, Psychology, Montreal, Quebec, Canada; titesar@hotmail.com.

Copyright

(Copyright © 2011, Mary Ann Liebert Publishers)

DOI

10.1089/neu.2010.1615

PMID

21219259

Abstract

Sports concussions affect thousands of Americans every year and are a major public health concern. Still, litte is known about the long-term and cumulative effects of concussions on brain neurophysiology. The principal objective of this study was to investigate the long lasting effects of multiple sports concussions on sensorimotor integration and somatosensory processing in a sample of 12 concussed athletes and 14 non-concussed athletes of similar age (mean = 23 years) and education (mean = 16 years). Right median nerve stimulation was paired with transcranial magnetic stimulation (TMS) of the left primary motor cortex to investigate sensorimotor integration with short latency afferent inhibition (SAI) and long latency afferent inhibition (LAI) at five interstimulus intervals (18, 20, 22, 100, 200 ms). Somatosensory evoked potentials (SEP) were recorded from the left centro-parietal region. Primary motor cortex inhibitory mechanisms were also investigated with three TMS protocols : cortical silent period (CSP), long interval intracortical inhibition (LICI) and short interval intracortical inhibition (SICI). No differences were observed between groups for SAI, LAI and SEP. However, CSP duration was prolonged and LICI was enhanced in the concussed group. These findings suggest that multiple sport concussions lead to specific, long-term neurophysiological dysfunctions of intracortical inhibitory mechanisms in primary motor cortex while somatosensory processing and sensorimotor integration are spared. This study provides additional evidence for the presence of specific and stable alterations in primary motor cortex presumably reflecting GABAB receptor activity that may be of clinical value for prognosis and diagnosis.

Language: en