Table 3.
Evidence table
| Reference | Patient population | Test(s) | Design | Results | Comments |
|---|---|---|---|---|---|
| Slobounov et al, 2012 | Penn State University, 380 contact sport athletes (football, rugby, ice hockey, etc) | NP, EEG, and objective balance testing | Baseline testing to all 380 participants, then follow-up testing of the 49 who sustained concussions (at days 7, 14, and 30 and at 6 and 12 mo post-mTBI) | For concussed participants, an increase COP area % was observed, on ave, 15% higher than baseline at day 15 post-mTBI, 3% on day 30. EEG study showed that those with > 20% alpha suppression at 7 d post-mTBI never returned to baseline levels by 12 mo. | Decreased proprioceptive ability and lingering effects of mTBI on the motor cortex in chronic-phase, post-RTP athletes |
| De Beumont et al, 2011 | 21 Active college level football players w/ concussion at least 9 mo prior, and 15 w/o hx of concussion | NP testing to determine asymptomatic status, then COP tests in quiet standing | All participants performed two 30-s trials in quiet standing | Significantly greater COP oscillations, greater variations in sagittal plane sway in chronic-phase mTBI group compared with control | Decreased proprioceptive ability in chronic-phase, post-RTP athletes |
| Henry et al, 2011 | 10 Active college-level football players with hx of mTBI, and 10 w/o hx of concussion | NP testing to determine asymptomatic status, then fMRI spectroscopy to look for metabolic changes in subacute/chronic mTBI group | fMRI to concussion athletes 6 mo postinjury compared with injury-free teammates | Decrease of N-acetylaspartate levels in the M1 cortex in chronic-phase mTBI group compared with control | Decreased N-acetylasparatate levels shown in previous studies to correlate with acute neuronal damage and mitochondrial dysfunction22,23 |
| De Beumont et al, 2007 | University of Montreal, varsity football players, 15 with 1 concussion, 15 with 2-5 concussions, and 15 with no concussions | NP testing to determine asymptomatic status, then TMS to all participants | TMS performed to all athletes to compare all 3 groups | Elongated CSP following TMS to concussion group compared with control. Also, an increase in CSP from multiple-mTBI group to single-mTBI group | Lingering effect of mTBI in chronic-phase, post-RTP athletes |
| Slovounov et al, 2007 | Penn State University, 160 male and female varsity rugby athletes with no hx of concussion | NP testing to baseline and after concussion, stereovisual testing in virtual reality setting using body sensors and force plate | Baseline stereovisual testing, retest for 39 athletes postconcussion at days 10, 17, and 30. Nine athletes having 2nd concussion in 1 year's time retested at days 10, 17, and 30 | At day 17 post RTP, 1st concussion group showed a 40% decrease of COP coherence to “moving room scene,” 2nd concussion group showed 60% decrease on day 17, while asymptomatic and again having returned to play. At day 30 in the 2nd concussion group, there was still a 35% decrease from baseline testing | Decreased rate of recovery as seen in proprioception and body awareness/coordination study, despite RTP in single- and multiple-concussed athletes |
COP, center of presure; EEG, electroencephalography; fMRI, functional magnetic resonance imaging; mTBI, mild traumatic brain injury; NP, neuropsychological; RTP, return-to-play.