Selective head cooling in the acute phase of concussive injury: a neuroimaging study.

Introduction: Neurovascular decoupling is a common consequence after brain injuries like sports-related concussion. Failure to appropriately match cerebral blood flow (CBF) with increases in metabolic demands of the brain can lead to alterations in neurological function and symptom presentation. Therapeutic hypothermia has been used in medicine for neuroprotection and has been shown to improve outcome. This study aimed to examine the real time effect of selective head cooling on healthy controls and concussed athletes via magnetic resonance spectroscopy (MRS) and arterial spin labeling (ASL) measures. Methods: 24 participants (12 controls; 12 concussed) underwent study procedures including the Post-Concussion Symptom Severity (PCSS) Rating Form and an MRI cooling protocol (pre-cooling (T1 MPRAGE, ASL, single volume spectroscopy (SVS)); during cooling (ASL, SVS)). Results: Results showed general decreases in brain temperature as a function of time for both groups. Repeated measures ANOVA showed a significant main effect of time (F = 7.94, p < 0.001) and group (F = 22.21, p < 0.001) on temperature, but no significant interaction of group and time (F = 1.36, p = 0.237). CBF assessed via ASL was non-significantly lower in concussed individuals at pre-cooling and generalized linear mixed model analyses demonstrated a significant main effect of time for the occipital left ROI (F = 11.29, p = 0.002) and occipital right ROI (F = 13.39, p = 0.001). There was no relationship between any MRI metric and PCSS symptom burden. Discussion: These findings suggest the feasibility of MRS thermometry to monitor alterations of brain temperature in concussed athletes and that metabolic responses in response to cooling after concussion may differ from controls.

AOA Critical Issues: Dichotomies in Leadership. Presidential Address to the AOA, June 17, 2022.

ABSTRACT: This speech was given at the 2022 American Orthopaedic Association (AOA) meeting in Providence, Rhode Island, on June 17, 2022, and discusses the most important elements of leadership. A sense of extreme ownership is required for effective leadership. Ownership allows leaders to delegate responsibilities to others and to instill confidence and trust in the people closest to them. True leaders recognize that every situation creates value, regardless of the outcome, because each and every encounter is an opportunity to learn. Oftentimes, a situation creates a natural dichotomy or controversy. Good leaders must recognize this dichotomy and balance the decision-making that is required for such an occurrence for the ultimate good of the individual or organization. True leaders will include rather than exclude the people around them and will graduate the responsibilities of individuals as the skills and trust of those individuals develop. Those in charge must also recognize that leadership includes intelligence, compassion, and instinct. Leaders who are health-care providers must keep patient care as the true "North Star" so that appropriations of space, personnel, and finances are maximally utilized. Finally, true leaders achieve their goals through the core principles of balance, orchestration, growth, inclusion, and envision.

Effects of Blood Flow Restriction Training on Clinical Outcomes for Patients With ACL Reconstruction: A Systematic Review.

CONTEXT: Knee muscle atrophy and weakness are common impairments after anterior cruciate ligament (ACL) reconstruction. Blood flow restriction (BFR) training represents a new approach to treat such impairments. However, limited evidence currently exists to support this intervention in related patients. OBJECTIVE: To appraise literature comparing the effects of BFR training with conventional therapy on knee muscle morphological and strength properties in ACL-reconstructed patients. DATA SOURCES: PubMed, SPORTDiscus, CINAHL, and Cochrane Central Register databases were searched for relevant articles from January 1991 through April 2021. STUDY SELECTION: Articles were minimum Level 3 evidence focusing on knee muscle morphologic as well as extensor and flexor strength outcomes in ACL-reconstructed patients of all graft types. STUDY DESIGN: Systematic review. LEVEL OF EVIDENCE: Level 2. DATA EXTRACTION: Critical appraisal instruments (Downs and Black checklist, Cochrane Collaboration tool, ROBINS-1 tool) were used to evaluate study quality. We independently calculated effect sizes (ESs) (Cohen d) between groups in each study. The Strength of Recommendation Taxonomy grading scale was used for clinical recommendations. RESULTS: Six articles (4 randomized control studies, 1 nonrandomized study, and 1 case-control study) met inclusion criteria. Exercises paired with BFR training included open kinetic chain, closed kinetic chain, and passive applications. Diverse assessments and time of intervention were observed across studies. ESs ranged from trivial to large in favor of BFR training for muscle morphological (d = 0.06 to 0.81) and strength assessments (d = -0.12 to 1.24) with CIs spanning zero. CONCLUSION: At this time, grade B or inconsistent and limited-quality patient-oriented evidence exists to support using BFR training to improve or maintain thigh muscle size as well as knee extensor and flexor strength in ACL-reconstructed patients. ESs indicated no consistent clinically meaningful differences when compared with conventional therapy. Subsequent analyses should be repeated as new evidence emerges to update practice guidelines.

Head acceleration event exposure and cognitive and functional outcomes: a comparison of multiple football seasons.

Athletes in contact sports are exposed to repetitive impacts as an inherent part of sport. There is concern over the accumulative effect; however, much is still unknown regarding their short-term effects. This study investigated impact accumulation and outcomes over three seasons (2015, 2017, 2019) in NCAA Football Bowl Subdivision players. Impacts were recorded using helmet accelerometers, and virtual reality testing (VR) was done across the season. Incidence rates for impacts (total; ≥25 G to <80 G; ≥80 G) all significantly differed by season (p < 0.05). VR scores changed across the seasons, specifically significant decreases in spatial memory (p < 0.05) in 2015, significant changes in balance and spatial memory (p < 0.05) in 2017, and no significant changes in 2019. Linear regressions predicting VR change score by impact incidence rate were nonsignificant. Monitoring exposure to impacts and changes in outcomes is useful; however, results are fluid, and many factors could indirectly have protective effects on athletes.

Treatment, Return to Play, and Performance Following Meniscus Surgery.

PURPOSE OF REVIEW: The standard of care in meniscal tear management is constantly evolving, especially for athletes and high-demand patients. Meniscus repairs, meniscus transplants, and partial meniscectomies are commonly performed, and rehabilitation methods following these operations are becoming more sophisticated. The ultimate goal of these procedures is returning patients to full activity with minimal risks. Return to play should be systematic, pathology dependent, and individualized to an athlete's needs, expectations, and level of play. This article provides a review of the current treatment modalities of meniscus tears, the rehabilitation protocols following each modality, and the return to play criteria that must be met before releasing the player to competition. In addition, it overviews articles that describe performance outcomes of patients that have undergone meniscus surgery. RECENT FINDINGS: Current research shows high return to play rates for athletes that undergo meniscus surgery and describes effective rehabilitation protocols to facilitate recovery. There is an increased emphasis on meniscus preservation in recent literature. In addition, meniscus allograft transplantation has demonstrated its efficacy as a salvage procedure and has become a stronger consideration in the athlete with meniscus pathology. No standardized return to play protocol can be applied uniformly to all kinds of meniscal surgeries, and two athletes with the same pathology cannot be expected to follow identical paths towards full recovery. A multidisciplinary approach to care should be provided to the patients, and in the case of patients with high levels of athleticism, the road to recovery starts even before the injury itself.

The accumulation of subconcussive impacts on cognitive, imaging, and biomarker outcomes in child and college-aged athletes: a systematic review.

Examine the effect of subconcussive impact accumulation on cognitive/functional, imaging, and biomarker outcomes over the course of a single season, specifically in contact sport athletes at collegiate level or younger. Systematic review following PRISMA guidelines and using Oxford Center for Evidence-Based Medicine 2011 Levels of Evidence and Newcastle Ottawa Assessment Scale. PubMed MEDLINE, PsycInfo, SPORT-Discus, Web of Science. Original research in English that addressed the influence of subconcussive impacts on outcomes of interest with minimum preseason and postseason measurement in current youth, high school, or college-aged contact sport athletes. 796 articles were initially identified, and 48 articles were included in this review. The studies mostly involved male football athletes in high school or college and demonstrated an underrepresentation of female and youth studies. Additionally, operationalization of previous concussion history and concussion among studies was very inconsistent. Major methodological differences existed across studies, with ImPACT and diffusion tensor imaging being the most commonly used modalities. Biomarker studies generally showed negative effects, cognitive/functional studies mostly revealed no effects, and advanced imaging studies showed generally negative findings over the season; however, there was variability in the findings across all types of studies. This systematic review revealed growing literature on this topic, but inconsistent methodology and operationalization across studies makes it challenging to draw concrete conclusions. Overall, cognitive measures alone do not seem to detect changes across this timeframe while imaging and biomarker measures may be more sensitive to changes following subconcussive impacts.

The Tibial Tubercle-Trochlear Groove Distance/Trochlear Dysplasia Index Quotient Is the Most Accurate Indicator for Determining Patellofemoral Instability Risk.

PURPOSE: The primary aim of our study was to evaluate diagnostic accuracy of the tibial tubercle-trochlear groove (TT-TG) distance relative to associated quotients produced from trochlear width (TT-TG distance/TW) and trochlear dysplasia index (TT-TG distance/TDI) for detecting patellofemoral instability. Secondary aims included identifying thresholds for risk and comparing differences between cases and controls. METHODS: Consecutive sampling of electronic medical records produced 48 (21 males, 27 females) patellofemoral instability cases (19 ± 7 years old) and 79 (61 males, 18 females) controls (23 ± 4 years old) who had a history of isolated meniscal lesion, as evaluated by magnetic resonance imaging. Standardized methods were employed with measurements executed in a blinded and randomized manner. A receiver operating characteristic curve assessed accuracy by area under the curve (AUC). The index of union (IU) was employed to identify a threshold for risk. Two-sample t-tests examined group differences. P < .05 denoted statistical significance. RESULTS: The AUC values were .69 (.60, .79) for TT-TG distance, .81 (.73, .88) for TT-TG distance/TW, and .85 (.78, .91) for TT-TG distance/TDI. Thresholds were 14.7 mm for TT-TG distance, .36 for TT-TG distance/TW, and 1.88 for TT-TG distance/TDI. Cases demonstrated statistically significant (P < .001) greater values for each measure compared with controls: TT-TG distance (15.8 ± 4.2 mm vs 12.9 ± 3.6 mm, [1.4, 4.3]); TT-TG distance/TW (.51 ± .24 vs .31 ± .09, [.13, .27]); TT-TG distance/TDI (3.07 ± 1.55 vs 1.7 ± .7, [.9, 1.84]). CONCLUSION: The TT-TG distance, TT-TG distance/TW, and TT-TG distance/TDI measures were 69%, 81%, and 85%, respectively, accurate for determining patellofemoral instability risk. Thresholds for risk were 14.7 mm for TT-TG distance, .36 for TT-TG distance/TW, and 1.88 for TT-TG distance/TDI. The thresholds reported in this study may help in advancing clinical decision-making. LEVEL OF EVIDENCE: Level III, diagnostic retrospective comparative observatory trial.

Fluoroscopy-Guided Suture Anchor Placement Yields Excellent Accuracy for Arthroscopic Acetabular Labral Repair: A Cadaveric Study.

PURPOSE: To determine the accuracy of fluoroscopy-guided suture anchor placement for arthroscopic acetabular labral repair in cadaveric hip specimens. METHODS: Two sports medicine fellowship-trained surgeons performed arthroscopic hip surgery on 6 cadaveric specimens each. Suture anchors were placed at the 11-, 12-, 1-, 2-, 3-, and 4-o'clock positions of the acetabulum in each specimen using a previously described fluoroscopically guided technique. Gross dissection and thin-cut computed tomography scans were performed to assess for accuracy. The insertion angle between the subchondral bone and the drill bit immediately prior to suture anchor insertion was measured, and fluoroscopic visualization of the subchondral bone at each clock-face position was qualitatively graded as good, fair, or poor by 2 independent reviewers. RESULTS: Overall, 90.3% of attempts (65 of 72) were entirely intraosseous, 5.5% (4 of 72) perforated the articular cartilage, and 4.2% (3 of 72) perforated the far cortex, rates that are comparable with those in previous cadaveric studies. There was no statistically significant difference in accuracy between the surgeons (P = .42) or between the various clock-face positions (P = .63). Neither the insertion angle (P = .26) nor visualization of the subchondral bone (P = .35) was significantly correlated with accuracy by gross dissection. CONCLUSIONS: In a cadaveric hip arthroscopy model, fluoroscopy-guided suture anchor placement yields excellent accuracy rates, similar to non-image-guided techniques. CLINICAL RELEVANCE: Intra-articular suture anchor placement and intrapelvic suture anchor placement are known complications of arthroscopic acetabular labral repair. Fluoroscopically guided suture anchor placement can be a useful tool for hip arthroscopy surgeons performing acetabular labral repair and reconstruction, potentially reducing the risk of these complications.

Effects of sleep disturbance on functional and physiological outcomes in collegiate athletes: A scoping review.

OBJECTIVE: To investigate sleep disturbances and circadian timing changes on functional and physiological correlates specifically in collegiate athletes. DESIGN: Scoping Review. DATA SOURCES: PubMed MEDLINE, SPORT-Discus, CINAHL, ERIC ProQuest, Web of Science. ELIGIBILITY CRITERIA: Articles in English, studying college athletes 18-24 years old, employing a sleep measurement, and a comparison measure of cognitive, academic performance, athletic performance, injury rate, biomarkers and physiological measures, or imaging. RESULTS: Thirty articles met inclusion criteria. There was wide range of study design, sport studied, modality used to measure sleep, frequency of sleep measurements, and functional and physiological outcomes across studies. Sleep measurements varied greatly in frequency of data collection and type of measurement tool, with the majority using a sleep questionnaire. While all variables of interest were represented within the review, most had a focus on cognitive performance, athletic performance, or injury rate as a function of sleep. Studies using biomarkers and physiological measures or imaging were largely underrepresented. Few studies used biomarkers and physiological measures, and one study used imaging measures. Most studies in this review reported negative cognitive and academic outcomes with worse sleep quality and quantity. CONCLUSIONS: Sleep is critical to maintaining optimal health and collegiate athletes represent a unique population given their unique time constraints, stresses, and sleep behaviors. Findings on athletic performance and injury rate as a function of sleep were mixed. Employing standardized objective methodologies in future work will allow for better understanding of the influence of sleep on the overall well-being and performance of college athletes.

The American Board of Orthopaedic Surgery Response to COVID-19.

The COVID-19 pandemic has disrupted every aspect of society in a way never previously experienced by our nation's orthopaedic surgeons. In response to the challenges the American Board of Orthopaedic Surgery has taken steps to adapt our Board Certification and Continuous Certification processes. These changes were made to provide flexibility for as many Candidates and Diplomates as possible to participate while maintaining our high standards. The American Board of Orthopaedic Surgery is first and foremost committed to the safety and well-being of our patients, physicians, and families while striving to remain responsive to the changing circumstances affecting our Candidates and Diplomates.

Injury and illness epidemiology at a summer sport-camp program, 2008 through 2011.

CONTEXT: University-sponsored summer sport camps often employ athletic trainers; however, there is a dearth of epidemiologic studies describing the injury and illness experience of sport-camp participants to guide clinicians. OBJECTIVE: To describe the injury and illness experience of youth participants at a university-sponsored summer sport-camp program during a 4-year period. DESIGN: Descriptive epidemiology study. SETTING: A National Collegiate Athletic Association Division I university that sponsored 76 to 81 camps for 28 sports each summer. PATIENTS OR OTHER PARTICIPANTS: A total of 44, 499 camp participants enrolled during the 4 years. Male and female participants ranged in age from 10 to 17 years and in athletic skill from novice to elite. MAIN OUTCOME MEASURE(S): Data from handwritten injury and illness log books, maintained by sports health care personnel, were accessed retrospectively, entered into an electronic spreadsheet, and coded. Data were applied to the National Athletic Injury/Illness Reporting System. Participant-personnel contacts, defined as any instance when a participant sought health care services from personnel, were calculated per 100 participants. Injury and illness rates were calculated per 10 ,000 exposures, measured in participant-days. The distribution of injury and illness conditions and affected body regions were calculated. RESULTS: There were 11 ,735 contacts, for an overall rate of 26 per 100 participants, and 4949 injuries and illnesses, for a rate of 1 per 10, 000 participant-days. Participants at single-sex camps were less likely to sustain injuries and illnesses than participants at coeducational camps (rate ratio [RR] = 0.49; 95% confidence interval = 0.45, 0. 35; P < .001, and RR = 0.47; 95% confidence interval = 0.43, 0.51; P < .001, respectively). The lower extremity was injured most frequently (27.9%). Most injury and illness conditions were dermatologic (37.1%). CONCLUSIONS: The contact and injury and illness differences observed among sports and between sexes demonstrated potential differences in the sports health care needs of camp participants. These data can be used to make evidence-based clinical decisions, such as determining injury-prevention strategies and sports health care staffing needs.

Comparative immediate functional outcomes among cryotherapeutic interventions at the ankle.

PURPOSE/BACKGROUND: There is a lack of evidence detailing the immediate effects of different cryotherapy interventions at the ankle on functional outcomes such as balance and jumping tasks in a physically active population; therefore, the purpose of the present study is to compare the immediate effects of varied modes of cryotherapy applications to the ankle joint on Star Excursion Balance Test and vertical jump height performance. The authors hypothesized that cryotherapy would acutely decrease performance when compared to a control, and that concomitant compression would further hinder outcomes. METHODS: A crossover study was conducted in a controlled laboratory setting. Thirty (9 men, 21 women) participants (20.6 ± 1.0 years, 1.7 ± 0.1 m, 67.5 ± 11.7 kg) were enrolled. The independent variable was treatment mode; no ice, ice without compression and ice with compression. Dependent variables included center of pressure (COP) excursions, dynamic balance reach distances and vertical jump height for the dominant leg. Participants underwent three separate testing sessions separated by 72-hour rest intervals. The order of treatment and performance measures was randomized to prevent order effects. Normalized dynamic balance reach distances were assessed using the reliable modified Star Excursion Balance Test (SEBT). Center of pressure path length was assessed via a force platform during a single-legged static balance task under eyes-open and eyes-closed conditions. Relative vertical jump height was assessed using a single-legged vertical hop test. Group means and standard deviations were calculated by treatment mode. One-way analyses of variance with Tukey's post hoc test were used to calculate differences among treatment modes. p < 0.05 denoted statistical significance. RESULTS: No statistically significant differences existed for all the performance measures among treatment modes. CONCLUSIONS: These findings suggest no immediate differences in lower extremity performance outcome measures between the respective treatment modes applied to the ankle in a young, healthy and physically active population. Additional investigation is warranted to study the related delayed effects of these interventions. LEVELS OF EVIDENCE: III.

Standing flexion deficits predict self-reported outcomes in women after ipsilateral hamstring anterior cruciate ligament reconstruction.

PURPOSE: To profile the standing flexion angle and its association with subjective outcomes in ipsilateral hamstring tendon autograft anterior cruciate ligament-reconstructed patients. A secondary aim was to describe prone position-measured hamstring strength as a predictor of flexion angle. METHODS: Fifteen women (mean age, 20.47 ± 1.96 years; mean height, 1.69 ± 0.08 m; mean weight, 68.51 ± 12.64 kg; mean Tegner score, 6.80 ± 1.52), at a mean of 25.93 ± 11.25 months after surgery, were matched to 15 healthy participants by sex and approximate age, height, mass, and activity level (mean age, 20.93 ± 1.22 years; mean height, 1.65 ± 0.06 m; mean weight, 66.52 ± 10.69 kg; mean Tegner score, 6.13 ± 1.06). The independent variable was leg condition (involved, uninvolved, or matched). Dependent variables included goniometric flexion angle, Knee Injury and Osteoarthritis Outcome Score (KOOS) subscale scores, and absolute isokinetic hamstring strength. We used 1-tailed paired and 2-sample t tests to analyze side and group differences, respectively. Corresponding effect sizes (d) were also quantified. Linear regression assessed relations between flexion angle and the KOOS, as well as strength and flexion angle. P < .05 denoted statistical significance. RESULTS: The involved leg showed a significantly lesser flexion angle (112.9° ± 8.1°) compared with the uninvolved leg (116.1° ± 8.4°, P = .024) and matched leg (117.1° ± 4.5°, P = .044), with corresponding weak side (d = 0.380) and strong group (d = 0.958) effect sizes. Significant associations existed between flexion angle and subjective outcomes (r(2) = 60.3% and P = .001 for KOOS pain subscale, r(2) = 37.8% and P = .015 for KOOS subscale for function in activities of daily living, and r(2) = 39.2% and P = .012 for KOOS subscale for function in sports and recreation) for the involved leg. Hamstring strength was not a significant predictor of flexion angle for all legs (P > .05). CONCLUSIONS: Our results support the hypotheses that standing flexion angle insufficiencies exist for the involved leg, superior subjective outcomes are associated with greater flexion capacity, and hamstring strength at deep knee angles does not predict the standing flexion angle. LEVEL OF EVIDENCE: Level IV, therapeutic study, case series.

Injury/illness physician referral profile from a youth university-sponsored summer sport camp program.

Participation at university-sponsored summer sport camps is popular among youth athletes; however, there is a dearth of information to describe the injuries/illnesses experienced by camp participants. Data from a university-sponsored sport camp program from 2008 to 2011 were accessed retrospectively. The sport camp program had approximately 80 camps for 28 sports over 12 weeks annually. Male and female participants were 10 to 17 years old. Athletic trainers maintained medical documentation and provided medical referrals. Referrals were made for 9.9% (n=478) of all injuries/illnesses. Emergency department referrals were made for 2.9% of injuries/illnesses. University health services received 42.5% of referrals. There were 1.1 referrals per 100 participants. Boys comprised 60.7% of referrals. Rugby had the highest referral rate--5.0 per 100 participants. These data help increase physician preparedness and guide the delivery of sports medicine services for related sport camp programs as a means to improve quality of care delivered to participants.

The effects of two therapeutic patellofemoral taping techniques on strength, endurance, and pain responses.

OBJECTIVE: To compare the effects of taping techniques on clinical measures in patellofemoral pain syndrome (PFPS) patients. DESIGN: Crossover experimental design. SETTING: Controlled laboratory. PARTICIPANTS: Twenty physically active PFPS patients. MAIN OUTCOME MEASURES: Isokinetic strength and endurance, and perceived pain. RESULTS: Bilateral baseline differences existed for strength (involved = 1.8 ± 0.5 Nm/kg; uninvolved = 2.1 ± 0.5 Nm/kg; p = 0.001) and endurance (involved = 35.6 ± 14.0 J/kg; uninvolved = 40.2 ± 12.9 J/kg; p = 0.013). Strength (McConnell = 2.1 ± 0.6 Nm/kg, 95% SCI = (1.1, 4.2); Spider(®) = 2.1 ± 0.5 Nm/kg, 95% SCI = (0.9, 4.0)) and endurance (McConnell = 42.9 ± 13.8 J/kg, 95% SCI = (2.9, 11.6); Spider(®) = 42.5 ± 11.0 J/kg, 95% SCI = (2.6, -11.3)) increased when taped compared to baseline. Pain decreased during strength (baseline = 3.0 ± 2.2 cm; McConnell = 1.9 ± 1.7 cm, 95% SCI = (-1.8, -0.4); Spider(®) = 1.6 ± 2.0 cm, 95% SCI = (-2.0, -0.5)) and endurance (baseline = 2.5 ± 2.0 cm; McConnell = 1.5 ± 1.8 cm, 95% SCI = (-1.6, -0.4); Spider(®) = 1.1 ± 0.8 cm, 95% SCI = (-1.7, -0.5)) measurements when taped. Differences between taping techniques were insignificant. CONCLUSIONS: Taping improved clinical measures in PFPS patients. No differences existed between Spider(®) and McConnell techniques.

The use of magnetic resonance spectroscopy in the subacute evaluation of athletes recovering from single and multiple mild traumatic brain injury.

Advanced neuroimaging techniques have shown promise in highlighting the subtle changes and nuances in mild traumatic brain injury (MTBI) even though clinical assessment has shown a return to pre-injury levels. Here we use ¹H-magnetic resonance spectroscopy (¹H-MRS) to evaluate the brain metabolites N-acetyl aspartate (NAA), choline (Cho), and creatine (Cr) in the corpus callosum in MTBI. Specifically, we looked at the NAA/Cho, NAA/Cr, and Cho/Cr ratios in the genu and splenium. We recruited 20 normal volunteers (NV) and 28 student athletes recovering from the subacute phase of MTBI. The MTBI group was categorized based upon the number of MTBIs and time from injury to ¹H-MRS evaluation. Significant reductions in NAA/Cho and NAA/Cr ratios were seen in the genu of the corpus callosum, but not in the splenium, for MTBI subjects, regardless of the number of MTBIs. MTBI subjects recovering from their first MTBI showed the greatest alteration in NAA/Cho and NAA/Cr ratios. Time since injury to ¹H-MRS acquisition was based upon symptom resolution and did not turn out to be a significant factor. We observed that as the number of MTBIs increased, so did the length of time for symptom resolution. Unexpected findings from this study are that MTBI subjects showed a trend of increasing NAA/Cho and NAA/Cr ratios that coincided with increasing number of MTBIs.

Residual brain dysfunction observed one year post-mild traumatic brain injury: combined EEG and balance study.

OBJECTIVES: There is still considerable debate and controversy about whether EEG can be used as a robust clinical tool for assessment of mild traumatic brain injury (MTBI). Nonhomogeneous subject populations, inaccurate assessment of severity of brain injury, time since injury when EEG testing was performed, the lack of EEG research conducted serially and in conjunction with other behavioral measures as injury evolves over time may contribute to the existing controversies. In this study, we implemented a concussion assessment protocol combining a series of EEG and balance measures throughout one year post-injury to document the efficacy of EEG and balance measures as relate to differential recovery of patients suffering from MTBI. METHODS: Three hundred and eighty subjects at risk for MTBI were initially recruited for baseline testing. Forty nine from this initial subjects pool subsequently suffered a single episode of concussive blow and were tested on day 7, 15, 30 days, 6 months and 12 months post-injury. EEGs were recorded while sitting, standing on the force plate and then on a foam base of support with eyes open/closed conditions. EEG alpha power (8-12 Hz) and its percent suppression from sitting to standing postures were computed. The center of pressure (COP) measures were obtained from the force platform and analyzed for eyes open and eyes closed conditions. RESULTS: Percent alpha power suppression from sitting to standing postural conditions significantly increased in MTBI subjects shortly after the injury (p<0.01). Percent alpha power suppression significantly correlated with increased area of COP during standing posture with eye closed (r(2)=0.53, p<0.01). The magnitude of alpha power suppression predicted the rate of recovery of this measure in sub-acute and chronic phases of injury (r(2)=0.609, p<0.01). Finally, 85% of MTBI subjects who showed more than 20% of alpha power suppression in the acute phase of injury did not return to pre-injury status up to 12 months post-injury. CONCLUSIONS: The efficacy of serially implemented EEG measures in conjunction with balance assessment over the course of MTBI evolution to document residual cerebral dysfunction was demonstrated. Specifically, alteration of EEG alpha power dynamics in conjunction with balance data in the acute phase of injury with respect to baseline measures may predict the rate of recovery from a single concussive blow. SIGNIFICANCE: Neurophysiological measures are excellent tools to assess the status and prognosis of patients with MTBI.

Alteration of brain default network in subacute phase of injury in concussed individuals: resting-state fMRI study.

There are a number of symptoms, both neurological and behavioral, associated with a single episode of r mild traumatic brain injury (mTBI). Neuropsychological testing and conventional neuroimaging techniques are not sufficiently sensitive to detect these changes, which adds to the complexity and difficulty in relating symptoms from mTBI to their underlying structural or functional deficits. With the inability of traditional brain imaging techniques to properly assess the severity of brain damage induced by mTBI, there is hope that more advanced neuroimaging applications will be more sensitive, as well as specific, in accurately assessing mTBI. In this study, we used resting state functional magnetic resonance imaging to evaluate the default mode network (DMN) in the subacute phase of mTBI. Fourteen concussed student-athletes who were asymptomatic based upon clinical symptoms resolution and clearance for aerobic exercise by medical professionals were scanned using resting state functional magnetic resonance imaging. Nine additional asymptomatic yet not medically cleared athletes were recruited to investigate the effect of a single episode of mTBI versus multiple mTBIs on the resting state DMN. In concussed individuals the resting state DMN showed a reduced number of connections and strength of connections in the posterior cingulate and lateral parietal cortices. An increased number of connections and strength of connections was seen in the medial prefrontal cortex. Connections between the left dorso-lateral prefrontal cortex and left lateral parietal cortex showed a significant reduction in magnitude as the number of concussions increased. Regression analysis also indicated an overall loss of connectivity as the number of mTBI episodes increased. Our findings indicate that alterations in the brain resting state default mode network in the subacute phase of injury may be of use clinically in assessing the severity of mTBI and offering some insight into the pathophysiology of the disorder.