Cortical excitability after pediatric mild traumatic brain injury

Trevor A Seeger; Adam Kirton; Michael J Esser; Clare Gallagher; Jeff Dunn; Ephrem Zewdie; Omar Damji; Patrick Ciechanski; Karen M Barlow

doi:10.1016/j.brs.2016.11.011

Cortical excitability after pediatric mild traumatic brain injury

Brain Stimul. 2017 Mar-Apr;10(2):305-314. doi: 10.1016/j.brs.2016.11.011. Epub 2016 Nov 19.

Authors

Trevor A Seeger¹, Adam Kirton¹, Michael J Esser², Clare Gallagher¹, Jeff Dunn¹, Ephrem Zewdie¹, Omar Damji³, Patrick Ciechanski¹, Karen M Barlow⁴

Affiliations

¹ Cumming School of Medicine, University of Calgary, Calgary, Canada; Hotchkiss Brain Institute, University of Calgary, Calgary, Canada; Alberta Children's Hospital Research Institute, Alberta Children's Hospital, Calgary, Canada.
² Cumming School of Medicine, University of Calgary, Calgary, Canada; Alberta Children's Hospital Research Institute, Alberta Children's Hospital, Calgary, Canada.
³ Cumming School of Medicine, University of Calgary, Calgary, Canada.
⁴ Cumming School of Medicine, University of Calgary, Calgary, Canada; Hotchkiss Brain Institute, University of Calgary, Calgary, Canada; Alberta Children's Hospital Research Institute, Alberta Children's Hospital, Calgary, Canada. Electronic address: karen.barlow@albertahealthservices.ca.

PMID: 27916406
DOI: 10.1016/j.brs.2016.11.011

Abstract

Introduction: Mild traumatic brain injury (mTBI) outcomes are variable, and 10-15% may suffer from prolonged symptoms beyond 3 months that impair the child's return to normal activities. Neurophysiological mechanisms of mTBI are incompletely understood, particularly in children, but alterations in cortical excitability have been proposed to underlie post-concussion syndrome. Improved understanding is required to advance interventions and improve outcomes.

Objective/hypothesis: To determine if cortical excitability is altered in children with mTBI, and its association with clinical symptoms.

Methods: This was a cross-sectional controlled cohort study. School-aged children (8-18 years) with mTBI were compared to healthy controls. Cortical excitability was measured using multiple TMS paradigms in children with (symptomatic) and without (recovered) persistent symptoms one-month post-injury. Primary outcome was the cortical silent period (cSP), a potential neurophysiological biomarker of GABAergic inhibition. Secondary outcomes included additional TMS neurophysiology, safety and tolerability. Associations between neurophysiology parameters and clinical symptoms were evaluated.

Results: Fifty-three children with mTBI (55% male; mean age 14.1 SD: 2.4 years; 35 symptomatic and 27 asymptomatic participants) and 28 controls (46% male; mean age 14.3 SD: 3.1 years) were enrolled. cSP duration was similar between groups (F (2, 73) = 0.55, p = 0.582). Log₁₀ long interval intracortical inhibition (LICI) was reduced in symptomatic participants compared to healthy controls (F (2, 59) = 3.83, p = 0.027). Procedures were well tolerated with no serious adverse events.

Conclusions: TMS measures of cortical excitability are altered at one month in children with mTBI. Long interval cortical inhibition is decreased in children who remain symptomatic at one month post-injury.

Keywords: Cortical silent period; Long interval intracortical inhibition; Mild traumatic brain injury; Pediatrics; Transcranial magnetic stimulus.

Publication types

Randomized Controlled Trial

MeSH terms

Adolescent
Brain Concussion / diagnosis*
Brain Concussion / physiopathology
Brain Concussion / therapy*
Cerebral Cortex / physiology*
Child
Cohort Studies
Cortical Excitability / physiology*
Cross-Sectional Studies
Evoked Potentials, Motor / physiology
Female
Humans
Male
Prospective Studies
Transcranial Magnetic Stimulation / methods*