Neurophysiological and cognitive impairment following repeated sports concussion injuries in retired professional rugby league players

Abstract

These findings of motor and cognitive changes, along with neurophysiological alterations, particularly with intracortical inhibition, nearly two decades post-concussion provides evidence for long-term sequelae for athletes with a history of repeated head trauma in contact sports.

Transcranial Magnetic Stimulation: A Tool for Quantifying Neurophysiological Changes in the Brain Following Concussion Injury in Sports

“…Categories were created to differentiate between concussion injury and recovery, as seen in short term studies [11]. Conversely long-term studies sort to understanding the physiology of persistent post-concussion symptoms [62], or the physiology of those with chronic changes years or decades later [63][64][65].…”

“…MT data was presented in eight studies [24,58,63,64,[74][75][76][77] with only one study reporting significantly increased MT in both symptomatic and asymptomatic concussed groups, compared to control [56]. Three studies reported latency data, with no difference between groups [65,74,78]. MEP amplitude presented in eight studies [24, 62-65, 74, 76] showed no differences between groups.…”

“…Intracortical inhibition was reported in all but one study [56]. Eleven studies presented cSP duration [24,[62][63][64][65][74][75][76][77][78][79][80]. Six studies reported significant lengthening of the cSP [24,62,63,[77][78][79], two studies reported significant shortening of the cSP [64,65], and three studies presented no change or mixed data [74,75,80].…”

“…Eleven studies presented cSP duration [24,[62][63][64][65][74][75][76][77][78][79][80]. Six studies reported significant lengthening of the cSP [24,62,63,[77][78][79], two studies reported significant shortening of the cSP [64,65], and three studies presented no change or mixed data [74,75,80]. Eleven studies included paired-pulse inhibitory measures [24,[62][63][64][65][75][76][77][78][79][80].…”

“…Six studies reported significant lengthening of the cSP [24,62,63,[77][78][79], two studies reported significant shortening of the cSP [64,65], and three studies presented no change or mixed data [74,75,80]. Eleven studies included paired-pulse inhibitory measures [24,[62][63][64][65][75][76][77][78][79][80]. Three of seven studies showed significant difference in SICI ratio between concussed and non-concussed controls [62,64,76].…”