High School Football Season Research Articles

Reduced Cortical Excitability is Associated with Cognitive Symptoms in Concussed Adolescent Football Players.

American tackle football is associated with high rates of concussion, leading to neurophysiological disturbances and debilitating clinical symptoms. Previous investigations of the neurophysiological effects of concussion have largely ignored aperiodic neurophysiological activity, which is a marker of cortical excitability. We examined whether concussion during a season of high school football is related to changes in aperiodic and periodic neurophysiological activity and whether any such changes are associated with clinical outcomes. Pre- and post-season resting-state magnetoencephalography (MEG) data were collected from 91 high school football players over as many as four seasons of play, for a total of 278 data collections. During these seasons of football play, a cohort of 10 individuals were diagnosed with concussion. MEG data were source-imaged, frequency-transformed and parameterized, and linear mixed models were used to examine effects of concussion on pre-to-post-season changes in neurophysiological activity. Scores on the Post-Concussive Symptom Inventory were correlated with pre-to-post-season neurophysiological changes to determine their clinical relevance. Concussion was associated with increased aperiodic exponents in superior frontal cortices, indicating a relative reduction in cortical excitability. This slowing of aperiodic neurophysiology mediated concussion effects on raw delta and gamma power and was associated with worse cognitive concerns across participants. Pre-to-post-season changes in aperiodic-corrected alpha and theta rhythmic activity were also decreased in posterior cortices in concussed players. These findings indicate that concussion alters both the excitability and rhythmic signaling of the cortex, with differing spatial topographies and implications for clinical symptoms.

Association of Auditory Interference and Ocular-Motor Response with Subconcussive Head Impacts in Adolescent Football Players.

The aim of this study was to examine whether neuro-ophthalmological function, as assessed by the King-Devick test (KDT), alters during a high school football season and to explore the role of auditory interference on the sensitivity of KDT. During the 2021 and 2022 high school football seasons, football players' neuro-ophthalmological function was assessed at five time points (preseason, three in-season, postseason), whereas control athletes were assessed at preseason and postseason. Two-hundred ten football players and 80 control athletes participated in the study. The year 1 cohort (n = 94 football, n = 10 control) was tested with a conventional KDT, whereas the year 2 cohort (n = 116 football, n = 70 control) was tested with KDT while listening to loud traffic sounds to induce auditory interference. There were improvements in KDT during a season among football players, regardless of conventional KDT (preseason 53.4 ± 9.3 vs. postseason 46.4 ± 8.5 sec; β = -1.7, SE = 0.12, p < 0.01) or KDT with auditory interference (preseason 52.3 ± 11.5 vs. postseason 45.1 ± 9.5 sec; β = -1.7, SE = 0.11, p < 0.001). The degree of improvement was similar between the tests, with no significant group-by-time interaction (β = -0.08, SE = 0.17, p = 0.65). The control athletes also improved KDT performance at a similar degree as the football cohorts in both KDT conditions. Our data suggest that KDT performance improves during a season, regardless of auditory interference or head impact exposure. KDT performance was not impacted by a noisy environment, supporting its sideline utility for screening more severe forms of injury.

Cognitive and Salience Network Connectivity Changes following a Single Season of Repetitive Head Impact Exposure in High School Football.

During a season of high school football, adolescents with actively developing brains experience a considerable number of head impacts. Our aim was to determine whether repetitive head impacts in the absence of a clinically diagnosed concussion during a season of high school football produce changes in cognitive performance or functional connectivity of the salience network and its central hub, the dorsal anterior cingulate cortex. Football players were instrumented with the Head Impact Telemetry System during all practices and games, and the helmet sensor data were used to compute a risk-weighted exposure metric (RWEcp), accounting for the cumulative risk during the season. Participants underwent MRI and a cognitive battery (ImPACT) before and shortly after the football season. A control group of noncontact/limited-contact-sport athletes was formed from 2 cohorts: one from the same school and protocol and another from a separate, nearly identical study. Sixty-three football players and 34 control athletes were included in the cognitive performance analysis. Preseason, the control group scored significantly higher on the ImPACT Visual Motor (P = .04) and Reaction Time composites (P = .006). These differences increased postseason (P = .003, P < .001, respectively). Additionally, the control group had significantly higher postseason scores on the Visual Memory composite (P = .001). Compared with controls, football players showed significantly less improvement in the Verbal (P = .04) and Visual Memory composites (P = .01). A significantly greater percentage of contact athletes had lower-than-expected scores on the Verbal Memory (27% versus 6%), Visual Motor (21% versus 3%), and Reaction Time composites (24% versus 6%). Among football players, a higher RWEcp was significantly associated with greater increments in ImPACT Reaction Time (P = .03) and Total Symptom Scores postseason (P = .006). Fifty-seven football players and 13 control athletes were included in the imaging analyses. Postseason, football players showed significant decreases in interhemispheric connectivity of the dorsal anterior cingulate cortex (P = .026) and within-network connectivity of the salience network (P = .018). These decreases in dorsal anterior cingulate cortex interhemispheric connectivity and within-network connectivity of the salience network were significantly correlated with deteriorating ImPACT Total Symptom (P = .03) and Verbal Memory scores (P = .04). Head impact exposure during a single season of high school football is negatively associated with cognitive performance and brain network connectivity. Future studies should further characterize these short-term effects and examine their relationship with long-term sequelae.

Longitudinal Associations of Clinical and Biochemical Head Injury Biomarkers With Head Impact Exposure in Adolescent Football Players

Consequences of subconcussive head impacts have been recognized, yet most studies to date have included small samples from a single site, used a unimodal approach, and lacked repeated testing. To examine time-course changes in clinical (near point of convergence [NPC]) and brain-injury blood biomarkers (glial fibrillary acidic protein [GFAP], ubiquitin C-terminal hydrolase-L1 [UCH-L1], and neurofilament light [NF-L]) in adolescent football players and to test whether changes in the outcomes were associated with playing position, impact kinematics, and/or brain tissue strain. This multisite, prospective cohort study included male high school football players aged 13 to 18 years at 4 high schools in the Midwest during the 2021 high school football season (preseason [July] and August 2 to November 19). A single football season. The main outcomes were NPC (a clinical oculomotor test) and serum levels of GFAP, UCH-L1, and NF-L. Participants' head impact exposure (frequency and peak linear and rotational accelerations) was tracked using instrumented mouthguards, and maximum principal strain was computed to reflect brain tissue strain. Players' neurological function was assessed at 5 time points (preseason, post-training camp, 2 in season, and postseason). Ninety-nine male players contributed to the time-course analysis (mean [SD] age, 15.8 [1.1] years), but data from 6 players (6.1%) were excluded from the association analysis due to issues related to mouthguards. Thus, 93 players yielded 9498 head impacts in a season (mean [SD], 102 [113] impacts per player). There were time-course elevations in NPC and GFAP, UCH-L1, and NF-L levels. Compared with baseline, the NPC exhibited a significant elevation over time and peaked at postseason (2.21 cm; 95% CI, 1.80-2.63 cm; P < .001). Levels of GFAP and UCH-L1 increased by 25.6 pg/mL (95% CI, 17.6-33.6 pg/mL; P < .001) and 188.5 pg/mL (95% CI, 145.6-231.4 pg/mL; P < .001), respectively, later in the season. Levels of NF-L were elevated after the training camp (0.78 pg/mL; 95% CI, 0.14-1.41 pg/mL; P = .011) and midseason (0.55 pg/mL; 95% CI, 0.13-0.99 pg/mL; P = .006) but normalized by the end of the season. Changes in UCH-L1 levels were associated with maximum principal strain later in the season (0.052 pg/mL; 95% CI, 0.015-0.088 pg/mL; P = .007) and postseason (0.069 pg/mL; 95% CI, 0.031-0.106 pg/mL; P < .001). The study data suggest that adolescent football players exhibited impairments in oculomotor function and elevations in blood biomarker levels associated with astrocyte activation and neuronal injury throughout a season. Several years of follow-up are needed to examine the long-term effects of subconcussive head impacts in adolescent football players.

Changes in resting state networks in high school football athletes across a single season.

The aim of this pilot cohort study was to examine changes in the organization of resting-state brain networks in high school football athletes and its relationship to exposure to on-field head impacts over the course of a single season. Seventeen male high school football players underwent functional magnetic resonance imaging and computerized neurocognitive testing (CNS Vital Signs) before the start of contact practices and again after the conclusion of the season. The players were equipped with helmet accelerometer systems (Head Impact Telemetry System) to record head impacts in practices and games. Graph theory analysis was applied to study intranetwork local efficiency and strength of connectivity within six anatomically defined brain networks. We observed a significant decrease in the local efficiency (-24.9 ± 51.4%, r = 0.7, p < 0.01) and strength (-14.5 ± 26.8%, r = 0.5, p < 0.01) of functional connectivity within the frontal lobe resting-state network and strength within the parietal lobe resting-state network (-7.5 ± 17.3%, r = 0.1, p < 0.01), as well as a concomitant increase in the local efficiency (+55.0 +/- 59.8%, r = 0.5, p < 0.01) and strength (+47.4 +/- 47.3%, r = 0.5, p < 0.01) within the mediotemporal networks. These alterations in network organization were associated with changes in performance on verbal memory (p < 0.05) and executive function (p < 0.05). We did not observe a significant relationship between the frequency or cumulative magnitude of impacts sustained during the season and neurocognitive or imaging outcomes (p > 0.05). Our findings suggest the efficiency and strength of resting-state networks are altered across a season of high school football, but the association of exposure levels to subconcussive impacts is unclear. The efficiency of resting-state networks is dynamic in high school football athletes; such changes may be related to impacts sustained during the season, though further study is needed.

Helmet Technology, Head Impact Exposure, and Cortical Thinning Following a Season of High School Football.

The purpose of this study was to compare the effects of wearing older, lower-ranked football helmets (LRank) to wearing newer, higher-ranked football helmets (HRank) on pre- to post-season changes in cortical thickness in response to repetitive head impacts and assess whether changes in cortical thickness are associated with head impact exposure for either helmet type. 105 male high-school athletes (NHRank = 52, NLRank = 53) wore accelerometers affixed behind the left mastoid during all practices and games for one regular season of American football to monitor head impact exposure. Pre- and post-season magnetic resonance imaging (MRI) were completed to assess longitudinal changes in cortical thickness. Significant reductions in cortical thickness (i.e., cortical thinning) were observed pre- to post-season for each group, but these longitudinal alterations were not significantly different between the LRank and HRank groups. Further, significant group-by-head impact exposure interactions were observed when predicting changes in cortical thickness. Specifically, a greater frequency of high magnitude head impacts during the football season resulted in greater cortical thinning for the LRank group, but not for the HRank group. These data provide preliminary in vivo evidence that HRank helmets may provide a buffer between the specific effect of high magnitude head impacts on regional thinning by dissipating forces more evenly throughout the cortex. However, future research with larger sample sizes, increased longitudinal measures and additional helmet technologies is warranted to both expand upon and further validate the present study findings.

A-09 Challenges in Measuring Repetitive Head Impacts, Cognition, and Eye Movements in High School Football Players

Abstract Purpose: Assess the feasibility of measuring Repetitive Head Impacts (RHI), cognition, and eye movements across a single season of high school football. Methods: Twelve players were provided an instrumented mouthguard (3200 Hz; Prevent Biometrics, Edina, MA) to evaluate RHI. Mouthguard use was assessed by total impacts and number of games/practices. Seven players also agreed to complete cognitive (ImPACT) and custom eye-tracking (500 Hz; EyeLink II) assessments pre-, mid-, and post-season. Multiple repeated measure ANOVA’s were completed using standard composite scores for ImPACT and oculomotor metrics. Results: Fifty percent of players ever used their mouthguard, and substantial variability in total impacts (M = 86.5, SD = 98.0, Range = 7–277) and number of games/practices (M = 9.8, SD = 7.6, Range = 2–23) were observed among players who did use their mouthguard. Specific completion rates for the 3 cognitive and 3 eye-tracking assessments were 71% each, and 57% of players completed all 6 scheduled assessments. Repeated measures ANOVA indicated Visual Motor Speed (VMS) improved between assessments (p = 0.015). Post hoc analysis showed both VMS and Verbal Memory increased from pre- to mid-season (−5.30(95%CI, −10.47 to −0.12), p = 0.046), (−0.20(95%CI, −13.00 to −1.41), p = 0.024). Conclusions: Variability in mouthguard use and missing assessment rates represent practical challenges in prospectively measuring RHI and utilizing multiple longitudinal assessment methods in high school football players. Although ImPACT results should be interpreted cautiously, future research should consider the potential role of practice effects and/or intentionally poor pre-season effort to explain the increase in performance during the season. A larger sample size will increase the possibility of measuring the effect of RHI on assessment outcomes.

Head Impact Telemetry System's Video-based Impact Detection and Location Accuracy.

This study aimed to quantify the Head Impact Telemetry (HIT) System's impact detection and location measurement accuracy using an impact biomechanics data set paired with video of high school football special teams plays. The head impact biomechanics data set and video were collected from 22 high school football players, wearing HIT System instrumented helmets, competing in 218 special teams plays over a single high school football season. We used two separate video analysis approaches. To quantify the impact detection accuracy, we evaluated the video for head impacts independently of the impact data collection triggers collected by the HIT System. Video-observed impacts matched to valid and invalid head impacts by the HIT System algorithm were categorized as true positives, false positives, false negatives, and true negatives. To quantify impact location accuracy, we analyzed video-synchronized head impacts for impact location independent of the HIT System's impact location measurement and quantified the estimated percent agreement of impact location between the HIT System recorded impact location and the impact location observed on video. The HIT System's impact-filtering algorithm had 69% sensitivity, 72% specificity, and 70% accuracy in categorizing true and non-head impact data collection triggers. The HIT System agreed with video-observed impact locations on 64% of the 129 impacts we analyzed (unweighted k = 0.43, 95% confidence interval = 0.31-0.54). This work provides data on the HIT System's impact detection and location accuracy during high school football special teams plays using game video analysis that has not been previously published. Based on our data, we believe that the HIT System is useful for estimating population-based impact location distributions for special teams plays.

THE EFFECTS OF INTERNAL JUGULAR VEIN COMPRESSION FOR PRESERVING WHITE MATTER INTEGRITY IN HIGH SCHOOL FOOTBALL PLAYERS COMPARISON OF HIGH VS LOW

Background:Repetitive head impacts experienced during competitive sports contribute to neurologic changes over the course of a season. Internal jugular vein compression, by means of an externally worn neck collar device has shown efficacy in mitigating white matter (WM) alterations following repeated head impact exposure. However, its relative effectiveness in high versus low head impact exposures is unknown.Hypothesis/Purpose:The purpose of this study was to investigate the effectiveness of an externally worn neck collar device in limiting WM alterations over a season of high school football in players who receive high and low cumulative head impact exposures over 90 g.Methods:213 male high-school football athletes were prospectively assigned to two study groups: a control group (non-collar; n=106) and an experimental group who wore the jugular vein compression collar during all practices and games (collar; n=107). MRI data was collected from all participants pre- and post-season. Fractional anisotropy (FA), and mean, axial and radial diffusivity (MD/AD/RD) were calculated to assess WM integrity at both time points. Cumulative head impact exposure was monitored by accelerometers attached to each athlete’s left mastoid process during every exposure. Participants were dichotomized into subgroups based on accumulated exposures to hits over 90 g, which divided the entire cohort into four subgroups, using a cut-off of 40 hits : (1) non-collar group (≥40 hits, n=57); (2) collar group (≥40 hits, n=51); (3) non-collar group (<40 hits, n=49); (4) collar group (<40 hits, n=56).Results:As seen in Table 1, in athletes with ≥40 hits, both the non-collar and collar group showed significant pre- to post- season reductions in MD, AD, and/or RD. The non-collar group with ≥40 hits also showed a significant increase in FA, MD, and AD. RD, FA, and MD changes were greater in the non-collar group compared to the control group with ≥40 hits, while AD changes were greater in the collar group compared to the non-collar group with ≥ 40 hits. The non-collar group with <40 hits presented significant pre- to post-season reductions in MD, AD, and RD that were greater than the collar group with < 40 hits (whom did not show pre-to post-season changes).Discussion & Conclusion:The present results provide support for internal jugular vein compression to protect the brain from both low- and high-level repeated head impact exposure. However, less consistent changes were observed for athletes exposed to repeated, high-level head impacts, warranting further investigation.Table 1.Number of WM voxels (1x1x1mm) with significant (p < .05 after correcting for multiple comparisons) pre- to post-season DTI changes and/or significant group difference (red indicates group difference for non-collar group; blue indicates group difference for collar group) for high and low head impact exposure FA ↓ MD↓ AD↓ RD↓ FA↑ MD↑ AD↑ RD↑ #hits ≥ 40 Noncollar,n= 5701390381 702965186110Collar, n=51013313350 0000Grp_diff-011511 24660-#hits <40 Noncollar,n= 4905925956340 0000Collar, n=560000 0000Grp_diff-308627611 ----

Oculomotor Response to Cumulative Subconcussive Head Impacts in US High School Football Players

Repetitive subconcussive head impacts in sports have emerged as a complex public health issue. Most of these head impacts remain asymptomatic yet have the potential to cause insidious neurological deficit if sustained repetitively. Near point of convergence (NPC) values have shown to reflect subclinical neuronal damage; however, the longitudinal pattern of NPC changes in association with subconcussive head impacts remains unclear. To examine the NPC response to recurring subconcussive head impacts in a single high school football season through a series of repeated measurements. This prospective case-series study of US varsity high school football players included baseline measurements of NPC, measurements at pregame and postgame points from 6 in-season games, and postseason follow-up measurements (a total of 14 points). An accelerometer-embedded mouthguard measured head impact frequency and magnitude from all practices and games. During the 6 games, players wore chest-strap heart rate monitors to record heart rate and estimate their excess postexercise oxygen consumption, accounting for possible physical exertion effects on NPC values. Players participated in practices and games with no restriction. Near point of convergence. The 12 included players were all boys, with a mean (SD) age of 16.4 (0.5) years. A total of 8009 head impacts, 177 907 g of peak linear acceleration, and 16 123 371 rad/s2 of peak rotational acceleration were recorded from the players in a single football season. There was a significant increase in NPC over time until the middle of the season (mean [SD] NPC: baseline, 5.25 [1.49] cm; pregame 3, 6.42 [1.93] cm; P = .01), which was significantly associated with subconcussive head impact frequency and magnitude (0.02 cm per 100 g of peak linear acceleration [SE, 0.0108; 95% CI, 0.0436-0.004]; P = .01; 0.023 cm per 10 000 rad/s2 of peak rotational acceleration [SE, 0.009; 95% CI, 0.041-0.0105]; P = .02). However, NPC values began to normalize toward baseline level from midseason (mean [SD] NPC: baseline, 5.25 [1.49] cm; pregame 6, 5.75 [2.23] cm; P = .32), as supported by a significant quadratic trend (β [SE], -0.002 [0.001] cm/d; P = .003), while participants continued to incur subconcussive head impacts. This longitudinal case series study suggests that NPC can be perturbed over the long term by subconcussive head impacts but may normalize over time. The oculomotor system may have an adaptational capacity to subclinical head impacts, yet the mechanism for such remains an open question and warrants further investigation.

Microstructural alterations of cortical and deep gray matter over a season of high school football revealed by diffusion kurtosis imaging

ObjectivesTo probe microstructural changes that are associated with subconcussive head impact exposure in deep and cortical gray matter of high school football players over a single season. MethodsPlayers underwent diffusion kurtosis imaging (DKI) and quantitative susceptibility mapping (QSM) scans. Head impact data was recorded. Association between parametric changes and frequency of frontal head impact was assessed. ResultsIn deep gray matter, significant decreases in mean kurtosis (MK) and increases in mean diffusivity (MD) over the season were observed in the thalamus and putamen. Correlations between changes in DKI metrics and frequency of frontal impacts were observed in the putamen and caudate.In cortical gray matter, decreases in MK were observed in regions including the pars triangularis and inferior parietal. In addition, increases in MD were observed in the rostral middle frontal cortices. Negative correlations between MK and frequency of frontal impacts were observed in the posterior part of the brain including the pericalcarine, lingual and middle temporal cortices.Magnetic susceptibility values exhibited no significant difference or correlation, suggesting these diffusion changes common within the group may not be associated with iron-related mechanisms. ConclusionMicrostructural alterations over the season and correlations with head impacts were captured by DKI metrics, which suggested that DKI imaging of gray matter may yield valuable biomarkers for evaluating brain injuries associated with subconcussive head impact. Findings of associations between frontal impacts and changes in posterior cortical gray matter also indicated that contrecoup injury rather than coup injury might be the dominant mechanism underlying the observed microstructural alterations. Advances in knowledgeSignificant microstructural changes, as reflected by DKI metrics, in cortical gray matter such as the rostral middle frontal cortices, and in deep gray matter such as the thalamus were observed in high school football players over the course of a single season without clinically diagnosed concussion.QSM showed no evidence of iron-related changes in the observed subconcussive brain injuries.The detected microstructural changes in cortical and deep gray matter correlated with frequency of subconcussive head impacts. Implications for patient careDKI may yield valuable biomarkers for evaluating the severity of brain injuries associated with subconcussive head impacts in contact sport athletes.

White Matter Changes Related to Subconcussive Impact Frequency during a Single Season of High School Football.

The effect of exposing the developing brain of a high school football player to subconcussive impacts during a single season is unknown. The purpose of this pilot study was to use diffusion tensor imaging to assess white matter changes during a single high school football season, and to correlate these changes with impacts measured by helmet accelerometer data and neurocognitive test scores collected during the same period. Seventeen male athletes (mean age, 16 ± 0.73 years) underwent MR imaging before and after the season. Changes in fractional anisotropy across the white matter skeleton were assessed with Tract-Based Spatial Statistics and ROI analysis. The mean number of impacts over a 10-g threshold sustained was 414 ± 291. Voxelwise analysis failed to show significant changes in fractional anisotropy across the season or a correlation with impact frequency, after correcting for multiple comparisons. ROI analysis showed significant (P < .05, corrected) decreases in fractional anisotropy in the fornix-stria terminalis and cingulum hippocampus, which were related to impact frequency. The effects were strongest in the fornix-stria terminalis, where decreases in fractional anisotropy correlated with worsening visual memory. Our findings suggest that subclinical neurotrauma related to participation in American football may result in white matter injury and that alterations in white matter tracts within the limbic system may be detectable after only 1 season of play at the high school level.

Exploring relationships between the coach-initiated motivational climate and psychological coping skills over the high school American football season

This study investigated the relationship between the perceived coach-initiated motivational climate and psychological coping skills over a competitive high school football season as well as changes in perceptions of the climate over the season. Near the beginning (Time 1) and end of the season (Time 2), 101 players from five competitive high school American football programs completed the Perceived Motivational Climate in Sport Questionnaire-2 and the Athletic Coping Skill Inventory-28. A hierarchical linear regression revealed that Time 2 task-involving climate predicted Time 2 psychological coping skills when controlling for Time 1 psychological coping skills. Repeated measure multivariate analysis of variance results demonstrated that players perceived a decrease in the task-involving climate and an increase in the ego-involving climate over the course of the competitive season. These results add to the research on the positive role of a task-involving climate in the sport domain. Additionally, this research provides insight into how perceptions of the coach-initiated motivational climate can shift over the course of the competitive season.

A Prospective Evaluation on the Effects of One High School Football Season on Neurocognitive Test Scores in High School Football Athletes

Subconcussive head impacts do not result in outward signs of neurological dysfunction, however they may have an effect on neurocognitive function. Limited research has indicated that negative changes in neurocognitive function occurs in high school football athletes as a result of one season of football. The purpose of this study was to prospectively evaluate the effects of one season of high school football on neurocognitive test scores. Results revealed a significant group and time interaction effect (p &lt; .001) for the Verbal Memory composite score of the ImPACT test. Further analysis revealed a significant difference in the Verbal Memory score between groups at postseason (p &lt; .01), with the football group scoring lower than the low contact group. It appears that one season of high school football may have a negative effect on the Verbal Memory composite score of the ImPACT test in high school football athletes.

Neck Collar with Mild Jugular Vein Compression Ameliorates Brain Activation Changes during a Working Memory Task after a Season of High School Football.

Emerging evidence indicates that repetitive head impacts, even at a sub-concussive level, may result in exacerbated or prolonged neurological deficits in athletes. This study aimed to: 1) quantify the effect of repetitive head impacts on the alteration of neuronal activity based on functional magnetic resonance imaging (fMRI) of working memory after a high school football season; and 2) determine whether a neck collar that applies mild jugular vein compression designed to reduce brain energy absorption in head impact through "slosh" mitigation can ameliorate the altered fMRI activation during a working memory task. Participants were recruited from local high school football teams with 27 and 25 athletes assigned to the non-collar and collar group, respectively. A standard N-Back task was used to engage working memory in the fMRI at both pre- and post-season. The two study groups experienced similar head impact frequency and magnitude during the season (all p > 0.05). fMRI blood oxygen level dependent (BOLD) signal response (a reflection of the neuronal activity level) during the working memory task increased significantly from pre- to post-season in the non-collar group (corrected p < 0.05), but not in the collar group. Areas displaying less activation change in the collar group (corrected p < 0.05) included the precuneus, inferior parietal cortex, and dorsal lateral prefrontal cortex. Additionally, BOLD response in the non-collar group increased significantly in direct association with the total number of impacts and total g-force (p < 0.05). Our data provide initial neuroimaging evidence for the effect of repetitive head impacts on the working memory related brain activity, as well as a potential protective effect that resulted from the use of the purported brain slosh reducing neck collar in contact sports.

Abnormalities in Diffusional Kurtosis Metrics Related to Head Impact Exposure in a Season of High School Varsity Football.

The purpose of this study was to determine whether the effects of cumulative head impacts during a season of high school football produce changes in diffusional kurtosis imaging (DKI) metrics in the absence of clinically diagnosed concussion. Subjects were recruited from a high school football team and were outfitted with the Head Impact Telemetry System (HITS) during all practices and games. Biomechanical head impact exposure metrics were calculated, including: total impacts, summed acceleration, and Risk Weighted Cumulative Exposure (RWE). Twenty-four players completed pre- and post-season magnetic resonance imaging, including DKI; players who experienced clinical concussion were excluded. Fourteen subjects completed pre- and post-season Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT). DKI-derived metrics included mean kurtosis (MK), axial kurtosis (K axial), and radial kurtosis (K radial), and white matter modeling (WMM) parameters included axonal water fraction, tortuosity of the extra-axonal space, extra-axonal diffusivity (De axial and radial), and intra-axonal diffusivity (Da). These metrics were used to determine the total number of abnormal voxels, defined as 2 standard deviations above or below the group mean. Linear regression analysis revealed a statistically significant relationship between RWE combined probability (RWECP) and MK. Secondary analysis of other DKI-derived and WMM metrics demonstrated statistically significant linear relationships with RWECP after covariate adjustment. These results were compared with the results of DTI-derived metrics from the same imaging sessions in this exact same cohort. Several of the DKI-derived scalars (Da, MK, K axial, and K radial) explained more variance, compared with RWECP, suggesting that DKI may be more sensitive to subconcussive head impacts. No significant relationships between DKI-derived metrics and ImPACT measures were found. It is important to note that the pathological implications of these metrics are not well understood. In summary, we demonstrate a single season of high school football can produce DKI measurable changes in the absence of clinically diagnosed concussion.

ACL Rupture in Collegiate Wrestler

Objective: To educate others on unique Anterior Cruciate Ligament tears and percentage of usage of the ACL in normal daily function. Background: Patient is an eighteen year old male participating in wrestling and football at the time of the injury. Patient now only participates in wrestling. No previous knee or chronic injuries were reported prior to this injury. Patient was playing football during the time of injury. The patient stated that he planted his foot down and was tackled at the same time when the injury occurred. The patient felt his knee twist and buckle. Patient complained of clicking inside the knee and had minimal swelling. He also complained of it being difficult to bear weight at the time. The patient did not seek further treatment until two months after the injury occurred when he received an MRI. His MRI showed a positive finding for an Anterior Cruciate Ligament rupture. His previous Athletic Trainer could not find a positive diagnosis for the patient prior to the MRI. Differential Diagnosis: Possible meniscal or ACL injury. Treatment: Doctors officially diagnosed the injury as a complete rupture of the ACL. The patient did not receive surgery immediately. Doctors have stated that he only uses about 50% of his ACL on a daily basis compared to a normal person who uses about 95% of their ACL daily. Because of this, the patient played on his rupture for seven months before receiving surgery. He played a whole season of high school football and a whole season of wrestling his senior year with the ACL ruptured. The patient only used a brace for better comfort during the seven months. The patient then received reconstructive surgery to repair the rupture. A hamstring tendon graft was used to repair the ruptured ACL. Because a tendon was taken from the hamstring, patient experienced a tight ACL and hamstring of the left leg post-surgery. The patient participated in Physical Therapy for five months to strengthen and stretch the new ACL and hamstring. After completing five months of physical therapy, the patient joined a college wrestling team in August 2013. The athletic training staff at the university started him on a quadriceps and hamstring strengthening rehabilitation program for about one month. The staff also worked on continuous flexion and extension of the knee to where the patient could feel comfortable with doing activities with his knee. The patient continues to participate in daily stretching and strengthening protocols for his quadriceps and hamstring bilaterally. Deviation from the Expected/Uniqueness: The patient still participated on a fully ruptured ACL for seven months with just complaining of minimal pain and discomfort. The athlete chose to complete two seasons of activities instead of receiving surgery immediately. The ratio of people who rupture their ACL is about 5 in every 100,000 people. It is interesting that the high school clinician could not diagnose the injury until the patient received an MRI two months post-injury. The patient was also told by doctors that he only uses about 50% of his ACL on a daily basis compared to anyone else who uses their ACL about 95%. The patient felt comfortable with the ACL ruptured and changed any discomfort by just wearing a brace. Conclusions: Not many people can play on a ruptured ACL for seven months before receiving any surgical repairs. We need to keep this in mind as Athletic Trainers so we are not sending our athletes back on the field and possibly causing them more damage. The athlete continues stretching protocols daily. Key Words: rupture, ACL, Anterior Cruciate Ligament

Comparison of Indiana High School Football Injury Rates by Inclusion of the USA Football "Heads Up Football" Player Safety Coach.

Background:In Indiana, high school football coaches are required to complete a coaching education course with material related to concussion awareness, equipment fitting, heat emergency preparedness, and proper technique. Some high schools have also opted to implement a player safety coach (PSC). The PSC, an integral component of USA Football’s Heads Up Football (HUF) program, is a coach whose primary responsibility is to ensure that other coaches are implementing proper tackling and blocking techniques alongside other components of the HUF program.Purpose:To compare injury rates in Indiana high school football teams by their usage of a PSC or online coaching education only.Study Design:Cohort study; Level of evidence, 2.Methods:Athletic trainers (ATs) evaluated and tracked injuries at each practice and game during the 2015 high school football season. Players were drawn from 6 teams in Indiana. The PSC group, which used the PSC component, was comprised of 204 players from 3 teams. The “education only” group (EDU), which utilized coaching education only, was composed of 186 players from 3 teams. Injury rates and injury rate ratios (IRRs) were reported with 95% confidence intervals (CIs).Results:During 25,938 athlete-exposures (AEs), a total of 149 injuries were reported, of which 54 (36.2%) and 95 (63.8%) originated from the PSC and EDU groups, respectively. The practice injury rate was lower in the PSC group than the EDU group (2.99 vs 4.83/1000 AEs; IRR, 0.62; 95% CI, 0.40-0.95). The game injury rate was also lower in the PSC group than the EDU group (11.37 vs 26.37/1000 AEs; IRR, 0.43; 95% CI, 0.25-0.74). When restricted to concussions only, the rate was lower in the PSC group (0.09 vs 0.73/1000 AEs; IRR, 0.12; 95% CI, 0.01-0.94), although only 1 concussion was reported in the PSC group. No differences were found in game concussion rates (0.60 vs 4.39/1000 AEs; IRR, 0.14; 95% CI, 0.02-1.11).Conclusion:Findings support the PSC as an effective method of injury mitigation in high school football. Future research should seek to replicate this study using larger samples from additional states.

Changes in Resting State Functional Connectivity Across a Season of High School Football (I5-3A)

Changes in Resting State Functional Connectivity Across a Season of High School Football (I5-3A)

Changes in Resting State Functional Connectivity Across a Season of High School Football (P7.148)

Changes in Resting State Functional Connectivity Across a Season of High School Football (P7.148)