Metabolic changes in concussed American football players during the acute and chronic post-injury phases

<p>Abstract</p> <p>Background</p> <p>Despite negative neuroimaging findings many athletes display neurophysiological alterations and post-concussion symptoms that may be attributable to neurometabolic alterations.</p> <p>Methods</p> <p>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: 22.5 years) 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.</p> <p>Results</p> <p>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 recovery observed 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.</p> <p>Conclusions</p> <p>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 indicate that complex pathophysiological processes differ depending on the post-injury phase and the neurometabolite in question.</p

Neurocognitive Performance of Concussed Athletes When Symptom Free

Context: Concussed athletes may underreport concussion-related symptoms in order to expedite return to play. Whether neurocognitive impairments persist once concussion-related symptoms resolve has yet to be determined. Reliance on athlete-reported, postconcussion symptoms when making return-to-play decisions may expose athletes to subsequent injury if complete recovery has not occurred. Objective: To evaluate the presence of neurocognitive decrements in concussed athletes no longer reporting concussion-related symptoms. Design: Within-groups design. Setting: University research laboratory. Patients or Other Participants: Twenty-one National Collegiate Athletic Association Division I collegiate athletes (16 men, 5 women). Age = 19.81 ± 1.25 years, height = 180.95 ± 10.62 cm, mass = 93.66 ± 27.60 kg, and previous concussions = 1.76 ± 2.02. Main Outcome Measure(s): The ImPACT concussion assessment test was administered to concussed athletes at baseline, when symptomatic (within 72 hours of injury), and when asymptomatic. Index scores of verbal memory, visual memory, visual-motor speed, reaction time, and concussion-related symptoms were recorded at each session. The Symptom Assessment Scale was administered daily after injury to establish when the athlete became asymptomatic. Results: When assessed within 72 hours of concussion, 81% of the athletes showed deficits on at least 1 ImPACT variable. At the asymptomatic time point, 38% of the concussed athletes continued to demonstrate neurocognitive impairment on at least 1 ImPACT variable. Conclusions: Neurocognitive decrements may persist when athletes no longer report concussion-related symptoms. The exclusive use of symptom reports in making a return-to-play decision is not advised. A multifaceted approach to concussion assessment that includes evaluation of a myriad of functions is warranted

Test-Retest Reliability of Computerized Concussion Assessment Programs

Context: Computer-based neurocognitive assessment programs commonly are used to assist in concussion diagnosis and management. These tests have been adopted readily by many clinicians based on existing test-retest reliability data provided by test developers

Investigation of Baseline Self-Report Concussion Symptom Scores

Context: Self-reported symptoms (SRS) scales comprise one aspect of a multifaceted assessment of sport-related concussion. Obtaining SRS assessments before a concussion occurs assists in determining when the injury is resolved. However, athletes may present with concussion-related symptoms at baseline. Thus, it is important to evaluate such reports to determine if the variables that are common to many athletic environments are influencing them. Objective: To evaluate the influence of a history of concussion, sex, acute fatigue, physical illness, and orthopaedic injury on baseline responses to 2 summative symptom scales; to investigate the psychometric properties of all responses; and to assess the factorial validity of responses to both scales in the absence of influential variables. Design: Cross-sectional study. Setting: Athletic training facilities of 6 National Collegiate Athletic Association institutions. Patients or Other Participants: The sample of 1065 was predominately male (n = 805) collegiate athletes with a mean age of 19.81 +/- 1.53 years. Main Outcome Measure(s): Participants completed baseline measures for duration and severity of concussion-related SRS and a brief health questionnaire. Results: At baseline, respondents reporting a previous concussion had higher composite scores on both scales (P \u3c= .01), but no sex differences were found for concussion-related symptoms. Acute fatigue, physical illness, and orthopaedic injury increased composite SRS scores on both duration and severity measures (P \u3c= .01). Responses to both scales were stable and internally consistent. Confirmatory factor analysis provided strong evidence for the factorial validity of the responses of participants reporting no fatigue, physical illness, or orthopaedic injury on each instrument. Conclusions: A history of concussion, acute fatigue, physical illness, and orthopaedic injury increased baseline SRS scores. These conditions need to be thoroughly investigated and controlled by clinicians before baseline SRS measures are collected