Citation

Pearce AJ, Hoy KE, Rogers MA, Corp DT, Maller JJ, Drury HG, Fitzgerald PB. J. Neurotrauma 2014; 31(13): 1139-1145.

Affiliation

Deakin University, Melbourne, Victoria, Australia ; alan.pearce@deakin.edu.au.

Copyright

(Copyright © 2014, Mary Ann Liebert Publishers)

DOI

10.1089/neu.2013.3219

PMID

24579780

Abstract

This study investigated corticomotor excitability and inhibition, cognitive functioning and fine motor dexterity in retired elite and amateur Australian football (AF) players, who had sustained concussions during their playing careers. Forty male AF players who played at the elite level (n=20; mean age 49.7 ± 5.7 years) or amateur level (n=20; mean age 48.4 ± 6.9 years), and had sustained on average 3.2 concussions 21.9 years previously, were compared to 20 healthy age-matched male controls (mean age 47.56 ± 6.85 years). All participants completed assessments of fine dexterity, visuomotor reaction time, spatial working memory (SWM) and associative learning (AL). Transcranial magnetic stimulation (TMS) was used to measure corticospinal excitability: stimulus-response (SR) curves and motor evoked potential (MEP) 125% of active motor threshold (aMT); and intracortical inhibition: cortical silent period (cSP), short-interval intracortical inhibition (SICI) and long interval intracortical inhibition (LICI). Healthy participants performed better in dexterity (p = 0.003), reaction (p = 0.003) and movement time (p = 0.037) compared to both AF groups. Differences between AF groups were found in AL (p = 0.027) and SWM (P=0.024). TMS measures revealed both AF groups showed reduced cSP duration at 125% aMT (p > 0.001) and differences in SR curves (p > 0.001), compared to healthy controls. Similarly, SICI (p = 0.012) and LICI (p = 0.009) were reduced in both AF groups compared to controls. Regression analyses revealed a significant contribution to differences in motor outcomes with the three measures of intracortical inhibition. The measures of inhibition differed, however, in terms of which performance measure with which they had significant and unique predictive relationship reflecting the variety of participant concussion injuries. This study is the first to demonstrate differences in motor control and intracortical inhibition, in AF players who have sustained concussions during their playing career two decades previously.

Language: en