Neurologia

Henry et al. BMC Neurology 2011, 11:105 http://www.biomedcentral.com/1471-2377/11/105

RESEARCH ARTICLE

Open Access

Metabolic changes in concussed American football players during the acute and chronic post-injury phases
Luke C Henry1*, Sébastien Tremblay1, Suzanne Leclerc2, Abdesselam Khiat3, Yvan Boulanger3, Dave Ellemberg1,2 and Maryse Lassonde1

Abstract
Background: Despitenegative neuroimaging findings many athletes display neurophysiological alterations and post-concussion symptoms that may be attributable to neurometabolic alterations. Methods: The present study investigated the effects of sports concussion on brain metabolism using 1H-MR Spectroscopy by comparing a group of 10 non-concussed athletes with a group of 10 concussed athletes of the same age (mean: 22.5years) and education (mean: 16 years) within both the acute and chronic post-injury phases. All athletes were scanned 1-6 days post-concussion and again 6-months later in a 3T Siemens MRI. Results: Concussed athletes demonstrated neurometabolic impairment in prefrontal and motor (M1) cortices in the acute phase where NAA:Cr levels remained depressed relative to controls. There was some recoveryobserved in the chronic phase where Glu:Cr levels returned to those of control athletes; however, there was a pathological increase of m-I:Cr levels in M1 that was only present in the chronic phase. Conclusions: These results confirm cortical neurometabolic changes in the acute post-concussion phase as well as recovery and continued metabolic abnormalities in the chronic phase. The results indicatethat complex pathophysiological processes differ depending on the post-injury phase and the neurometabolite in question. Keywords: MRI spectroscopy, sports concussion, recovery, metabolism

Background The perception of sports concussions has undergone a gradual overhaul throughout the past decade where an injury that was once considered to be inconsequential has come to be understood within theneuropsychological and medical communities to be an injury with quantifiable changes to the brain that are both transient [1-3] and persistent [4-7]. According to the current literature, transient changes are by far more abundant as most of these occur within the acute phase where athletes exhibit neurocognitive changes [8-10] in addition to neurophysiological alterations [11-15]. Persistent changeshave also been documented [4-7,16-19], though some doubt

* Correspondence: luke.henry@umontreal.ca 1 Centre de Recherche en Neuropsychologie et Cognition, Department of Psychology, University of Montreal, Montréal, Québec, Canada Full list of author information is available at the end of the article

their clinical legitimacy, citing litigation and other secondary gains as confounds [20-23].There is a disproportionate amount of research focusing on the acute post-injury phase owing largely to the fact that this is where the most overt effects of a sports concussion can be detected. The acute post-injury phase has no strict cut-off but is generally understood to be within three months though 80-90% of patients exhibit full recovery within the first 10 days [24,25]. Thus the chronicphase is understood to be anywhere from three months and outward post-injury in accordance with the DSM-IV-TR definition of Post-concussion Syndrome [26]. Indeed, most of the quantifiable changes associated with sports concussion are either subclinical or recovered in the acute phase [25,27]. Typically, post-concussive symptoms all but disappear within 2-3 weeks of concussion [24,28,29] with only asmall percentage of cases exhibiting post-concussion effects past the acute phase

© 2011 Henry et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is...