Neuroimaging, wearable sensors, and blood-based biomarkers reveal hyperacute changes in the brain after sub-concussive impacts
Bibliographic record
Abstract
Impacts in mixed martial arts (MMA) have been studied mainly in regard to the long-term effects of concussions. However, repetitive sub-concussive head impacts at the hyperacute phase (minutes after impact), are not understood. The head experiences rapid acceleration similar to a concussion, but without clinical symptoms. We utilize portable neuroimaging technology – transcranial Doppler (TCD) ultrasound and functional near infrared spectroscopy (fNIRS) – to estimate the extent of pre- and post-differences following contact and non-contact sparring sessions in nine MMA athletes. In addition, the extent of changes in neurofilament light (NfL) protein biomarker concentrations, and neurocognitive/balance parameters were determined following impacts. Athletes were instrumented with sensor-based mouth guards to record head kinematics. TCD and fNIRS results demonstrated significantly increased blood flow velocity (p=0.01) as well as prefrontal (p=0.01) and motor cortex (p=0.04) oxygenation, only following the contact sparring sessions. This increase after contact was correlated with the cumulative angular acceleration experienced during impacts (p=0.01). In addition, the NfL biomarker demonstrated positive correlations with angular acceleration (p=0.03), and maximum principal and fiber strain (p=0.01). On average athletes experienced 23.9±2.9 g peak linear acceleration, 10.29±1.1 rad/s peak angular velocity, and 1,502.3±532.3 rad/s2 angular acceleration. Balance parameters were significantly increased following contact sparring for medial-lateral (ML) center of mass (COM) sway, and ML ankle angle (p=0.01), illustrating worsened balance. These combined results reveal significant changes in brain hemodynamics and neurophysiological parameters that occur immediately after sub-concussive impacts and suggest that the physical impact to the head plays an important role in these changes. : Brain injuries sustained during sport participation have received much attention since it is a common occurrence among participants. Although protective technologies have been developed over the years, the mechanism of injury is still unclear. There is less focus on the repetitive exposure to sub-concussive impacts on the functional integrity of the brain. Sub-concussive impacts are defined as a lesser impact force resulting in acceleration of the head without symptoms of concussion. Diminished neurocognitive performance has been associated with increased sparring exposure in amateur MMA/boxers suggesting that repeated sub-concussive blows may be just as harmful. However, no one has studied the potential effect of repeated sub-concussive head impacts at the hyperacute level defined as within minutes after impact. We apply novel mobile sensing tools such as head impact sensors and portable neuroimaging devices that allow us to examine possible physiological effects taking place within minutes of sub-concussive impacts which are generally transient, and have not been captured before due to limitations with clinical imaging. Based on previous studies, we developed a protocol to test real-world sub-concussive head impact effects on cerebral blood flow and activation patterns and demonstrate that significant changes can be observed immediately after impacts occur, which could lead to improved monitoring and management of injury risk in sport participation.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".