Seeger, Trevor A.Kirton, AdamEsser, Michael J.Gallagher, ClareDunn, Jeff F.Zewdie, Ephrem TakeleDamji, OmarCiechanski, PatrickBarlow, Karen M.2018-10-312018-10-312016-11-19Seeger, T. A., Kirton A., Esser, M. J., Gallagher, C., Dunn, J. F., Zewdie E. T., ... Barlow K. M. (2017). Cortical excitability after pediatric mild traumatic brain injury. "Brain Stimulation", 10(2), 305-314.1935-861Xhttp://hdl.handle.net/1880/108941Introduction: Mild traumatic brain injury (mTBI) outcomes are variable, and 10e15% 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 (8e18 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) ¼ 0.55, p ¼ 0.582). Log10 long interval intracortical inhibition (LICI) was reduced in symptomatic participants compared to healthy controls (F (2, 59) ¼ 3.83, p ¼ 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.enTranscranial magnetic stimulusMild traumatic brain injuryCortical silent periodPediatricsLong interval intracortical inhibitionjournal article10.1016/j.brs.2016.11.01110.11575/PRISM/33901