Repetitive head impacts and sport-related concussions are significant concerns in contact sports due to their potential adverse effects on brain health. This study investigated the association between head impact exposure (HIE) during varsity football games and short-term changes in cortical excitability of the primary motor cortex (M1) using transcranial magnetic stimulation (TMS). A convenience sample of forty-nine university-level male athletes (median [IQR] age: 23.0 [2.0] years] were recruited. Twenty-nine athletes wore instrumented mouthguards during a football game to measure HIE (head impact group). TMS measurements were conducted 24 hours before and 1-2 hours after the game. Another twenty control football athletes underwent a non-contact training session and underwent identical TMS assessments (control group). For the head impact group, the median [IQR] number of impacts (> 10g) per player during a game was 11.6 [15.0]; the magnitude of each head impact was 18.9 [7.1] g and the cumulative force sustained per player was 234 [312.9] g. TMS results showed that whereas short-interval intracortical inhibition (SICI) ratios increased by 0.054 (± 0.0614 ) in the head impact group in the hours following the game, it decreased by 0.0704 (±0.0352) in the control group within the same time interval following the non-contact training session. A 2X2 mixed ANOVA on SICI ratios showed a significant Time * Group interaction (F(1, 44) = 5.192, p = .028, η2 = 0.106). Neither the main effect of groups (head impact versus control; p = .058) nor the main effect of time (24 hours before sport vs 1-2 hours after sport; p = 0.756) on SICI measures reached statistical significance. The relationship between HIE (i.e., number, magnitude and cumulative forces of impacts) and SICI was also investigated using two-tailed Pearson’s correlations. SICI modulation following the game was found to be unrelated to the mean number of impacts (p˂ .05) as well as to the cumulative forces of impacts across low-magnitude impact ranges (p˂ .05). However, the observed SICI disinhibition following the game was significantly related to the number of high-magnitude head impacts beyond 40g (r(29)=-0.397, p = 0.041) and the cumulative forces beyond 40g (r(29)=-0.468, p = 0.014) after False Discovery Rate corrections for multiple comparisons were applied. Likewise, this SICI disinhibition strongly correlated with the number of head impacts over 60g (r(29)=-0.629, p < 0.001) and cumulative forces over 60g (r(29)=-0.648, p = 0.014). Athletes exposed to subconcussive hits associated to a football game exhibit abnormal M1 corticomotor inhibition function, particularly when recorded impact magnitude ranges above 40g. Given the deleterious effects of decreased inhibition on motor control and balance, systematically tracking head impact forces at each game and practice with contacts could reveal useful for injury prevention in contact sports.

Background: Risk management of concussive blows to the head continues to be a challenge during several occupational and sports activities. Recent evidence suggests that there may be a significant negative relationship between neck strength/endurance and risk levels for concussion. (Collins 2014, Chavarro-Nieto 2021)

Purpose: To evaluate immediate differences in neck strength and endurance with and without customized, optimal mandibular interocclusal appliance positioning.

Design: Cohort Study Design with repeated testing.

Location: University Outpatient Physical Therapy Clinic

Methods: 12 healthy participants (6 females/6 males) ages >18 yrs. were sampled by convenience. Inclusion criteria: normal cervical spine AROM, no recent head or neck trauma or surgery. Exclusion criteria: active cervical pain and any cervical spine postural abnormalities. Participants were fitted with a customized, mouth guard to properly align occlusal "bite" by a dentist while an orthopedic specialist, physical therapist assessed neck extension/flexion/rotation strength using the MicroFit® pressure gauge (Newtons) and grip strength using the Jamar hand dynamometer (kg/ psi). Last of all, timed isometric, cervical muscle contraction for neck flex/extension endurance was measured in seconds. Participants were tested in each activity without and then with the interocclusal appliance in place. Quality of life outcomes including the Neck Disability Index (NDI) and Disability Assessment of Shoulder & Hand (DASH) were used as psychosocial factors or covariates in all analyses.

Statistical Analysis: SPSS (vs.26.0, IBM Inc.) was used for descriptive statistics, paired T-Tests and 2-way repeated measures ANOVA to explore differences at p = 0.05 with a Greenhouse-Geisser correction factor. Multivariate mixed effects models were constructed to assess separate and combined influences of gender and condition on strength and endurance outcomes.

Results: There were significant differences found in strength based on Condition (F (1) 8.834, p =.018) and Position (F (1,8) = 134.226, p < 0.001). Significant differences were also observed in grip strength without vs with the MG (t (8) = -6.378, p < 0.001). There were also significant differences in endurance in both directions: Neck Flex Endurance Test-Supine, (t (8)= -2.334, p= 0.048), Neck Ext Endurance Test-Prone, (t (8)= -4.078, p = 0.002).

Conclusions: Preliminary results indicate a significantly increased neck strength and endurance with a jaw interocclusal appliance for optimized positioning compared to no appliance use.

Clinical Relevance: Suggested gains in cervical spine strength and endurance may assist concussion risk management for contact sports at all levels. Preliminary results also suggest the need for further research about how proper jaw alignment might optimize neck muscle strength over a broad spectrum of subjects regardless of sex, ages or athletic ability.

BACKGROUND: Although safety of coal mine production facilities and regulations continue to improve around the world, gas explosion accidents still exist. Brain damage caused by coal mine gas explosions is a unique type of injury that is different from those that are generally seen by the explosions in wars and open spaces. Specifically, it is caused by the gas explosions from the superposition of repeated shock waves in a closed space and subsequent poisonous gases such as carbon monoxide (CO), which is a particular combination of physical and chemical injuries. Currently, there are many models of simple explosion shock wave or CO poisoning separately, and it was also reported both experimentally and clinically that these injuries do not only cause neurological dysfunction in acute phase, but is also more susceptible to develop neurodegenerative diseases in later stage. However, animal model of coal mine gas explosions with combined injuries does not exist currently, which prevent us from better understanding the difference between the single and combined injuries. We speculate that the combined injuries in coal mine gas explosions are more complex and severe than single injuries. This study will develop an animal model of gas explosion with combined injury by simulating gas explosion condition in coal mine tunnel, and use the model to understand the injury mechanism. We believe that the results will be useful for finding effective intervention methods and early treatments for patients in coal mine gas explosion accidents in the future.

METHODS: 20 adult Kunming white mice were divided into four groups: (1) Single gas explosion (SGE), received one explosion in a customized device; (2) Continuous CO poisoning (CCP), received four CO intraperitoneal injections within 24 hours; (3) SGE+CCP, received single explosion immediately followed by four CO injections within 24 hours; (4) Normal control (NC), received no injury. Behavior tests were performed three and seven days after injuries, then the animals were terminated for molecular biology tests.

RESULTS: The elevated plus maze test shows that in both 3 days and 7 days after injury，all injured groups presented significantly lower entering number when compared to NC group (P < 0.05); while SGE+CCP group also presented significantly lower entering number when compared to SGE and CCP groups (P < 0.05). RT-qPCR test shows that the brain tissues from SGE+CCP group presented significantly higher expression of IL-1β and TNF-α in 3 days after injury as well as higher expression of IL-6 and TNF-α in 7 days after injury when compared to other groups (P < 0.05).

CONCLUSIONS: A mouse model of coal mine gas explosion was developed. The combined injury was found to be more severe than the single injuries behaviourally, which may be related to the more severe inflammation.

OBJECTIVE: This abstract investigates the utility of Photobiomodulation (PBM) for Traumatic Brain Injury (TBI) treatment, aiming to expand therapeutic options beyond symptom management. It presents a synthesis of PBM's biological mechanisms, a compilation of clinical evidence, and an overview of its regulatory considerations.

METHODS AND MECHANISMS: PBM introduces red and near-infrared (NIR) light to targeted tissues, instigating a cascade of mitochondrial and cellular responses conducive to brain healing. This review elucidates PBM's action in modulating the mitochondrial electron transport chain, fostering gene transcription, and stimulating growth factor production. The activity also attenuates the excitotoxicity and inflammation which are characteristic of TBI.

CLINICAL EVIDENCE: Emphasizing clinical outcomes, substantial evidence from recent studies is presented, demonstrating PBM's effectiveness in improving cognitive and behavioral symptoms associated with TBI. Specific improvements in depression, sleep quality, cognitive function, and PTSD symptoms have been consistently reported. Notably, reaction time and grip strength enhancements serve as additional objective metrics of PBM's impact on neural recovery. Additionally, case reports involving former athletes with suspected chronic traumatic encephalopathy (CTE) reveal symptom alleviation in similar domains, reinforcing PBM's therapeutic potential even in a worrying spectrum of brain injuries. The parallels drawn between PBM's effects on CTE and clinical evidence for Alzheimer’s disease underlines a broader application for neurodegenerative disorders.

PERSONALIZATION THROUGH TECHNOLOGY: Recognizing the heterogeneity of TBI, this presentation advocates for the use of artificial intelligence (AI) to personalize PBM treatment. By analyzing individual brain activity through EEG and fMRI, AI algorithms can optimize PBM settings, tailoring the therapeutic regimen to patient-specific neurophysiological profiles.

PIVOTAL TRIAL AND REGULATORY PROGRESS: Looking forward, the presentation details the design of an upcoming multi-site randomized controlled trial (RCT) encompassing 280 subjects to substantiate PBM's efficacy for chronic TBI symptoms. This RCT is a critical step toward obtaining FDA clearance, a milestone that would validate PBM as a sanctioned therapy for TBI.

CONCLUSION: PBM is posited as an innovative, non-invasive treatment modality for TBI, distinguished by its ease of use and potential for integration into home settings. The convergence of promising clinical evidence and ongoing research underscores the need for continued exploration into PBM's capabilities. With AI's advent, the personalization of treatment parameters is anticipated to further enhance PBM's clinical applicability and outcomes in TBI recovery.