A Preliminary Study of the Effect of Early Aerobic Exercise Treatment for Sport-Related Concussion in Males.

OBJECTIVE: To study the effect of early prescribed aerobic exercise versus relative rest on rate of recovery in male adolescents acutely after sport-related concussion (SRC). DESIGN: Quasi-experimental design. SETTING: University sports medicine centers. PARTICIPANTS: Exercise group (EG, n = 24, 15.13 ± 1.4 years, 4.75 ± 2.5 days from injury) and rest group (RG, n = 30, 15.33 ± 1.4 years, 4.50 ± 2.1 days from injury). INTERVENTIONS: Exercise group performed a progressive program of at least 20 minutes of daily subthreshold aerobic exercise. Rest group was prescribed relative rest (no structured exercise). Both groups completed daily online symptom reports (Postconcussion Symptom Scale) for 14 days. MAIN OUTCOME MEASURES: Days to recovery after treatment prescription. Recovery was defined as return to baseline symptoms, exercise tolerant, and judged recovered by physician examination. RESULTS: Recovery time from initial visit was significantly shorter in EG (8.29 ± 3.9 days vs 23.93 ± 41.7 days, P = 0.048). Mixed-effects linear models showed that all symptom clusters decreased with time and that there was no significant interaction between treatment group and time. No EG participants experienced delayed recovery (>30 days), whereas 13% (4/30) of RG participants experienced delayed recovery. CONCLUSIONS: These preliminary data suggest that early subthreshold aerobic exercise prescribed to symptomatic adolescent males within 1 week of SRC hastens recovery and has the potential to prevent delayed recovery.

Evaluation of Executive Function and Mental Health in Retired Contact Sport Athletes.

OBJECTIVE: To compare retired professional contact sport athletes with age-matched noncontact sport athletes on measures of executive function and mental health. SETTING: The University Concussion Management Clinic. PARTICIPANTS: Twenty-one retired National Football League (NFL) and National Hockey League (NHL) players (mean age 56 years) and 21 age-matched noncontact sport athlete controls. DESIGNS: Case control. MAIN MEASURE: The self- and informant-reported Behavior Rating Inventory of Executive Function-Adult form (BRIEF-A); Wisconsin Card Sorting Test; Delis-Kaplan Executive Function System; Trail Making Part A and B; Wechsler Adult Intelligence Scale; Neuropsychological Assessment Battery; List Learning; Controlled Oral Word Association Test; Beck Depression Inventory; Beck Anxiety Inventory; and Personality Inventory of the DSM-5. RESULTS: Former NFL and NHL players perceived themselves to have some impairment in 2 of the 9 domains of executive function on the BRIEF-A; however, their informants reported no difference when compared with informants of noncontact athletes. No significant differences were found when comparing contact sport athletes with noncontact athletes on objective neuropsychological testing. Contact sport athletes qualified as clinically anxious and had more "unusual beliefs and experiences," although they remained within with age-based norms. CONCLUSION: Participation in contact sports at the professional level may not lead to later-life executive dysfunction, as the popular media and some research currently suggest.

An Exploratory Study of Mild Cognitive Impairment of Retired Professional Contact Sport Athletes.

OBJECTIVE: To test the hypothesis that mild cognitive impairment (MCI) rates are higher among retired professional contact sport athletes than in noncontact athlete controls and compare history of contact sports with other MCI risk factors. SETTING: University Concussion Management Clinic. PARTICIPANTS: Twenty-one retired National Football League and National Hockey League players and 21 aged-matched noncontact athlete controls. DESIGNS: Case-control. MAIN MEASURES: Comprehensive criteria were used to assess MCI based on the following: Wisconsin Card Sorting Test, Delis-Kaplan Executive Function System; Trail Making Parts A and B; Wechsler Adult Intelligence Scale-Third Edition subtests; Neuropsychological Assessment Battery Memory Module List Learning, Story Learning, and Naming subtests; and Controlled Oral Word Association Test. The Wide Range Achievement Test was used as a proxy measure for IQ. Atherosclerotic cardiovascular disease risk factors were self-reported and blood cholesterol was measured. Depression was measured by the Beck Depression Inventory-II (BDI). RESULTS: Eight contact sport athletes (38%) and 3 noncontact athletes (14%) met MCI criteria (P = .083). Contact sport athletes' scores were significantly worse on Letter Fluency and List B Immediate Recall. Contact athletes were more obese, had more vascular risk factors, and had higher scores on the BDI than controls. CONCLUSION: Athletes with a history of playing professional contact sports had more vascular risk factors and higher depression scores. MCI rates were somewhat higher, though not significant.

Intracranial pressure changes after mild traumatic brain injury: a systematic review.

OBJECTIVE: Intracranial pressure (ICP) after mild traumatic brain injury (mTBI) is poorly studied due to lack of sensitive non-invasive methods. The purpose of this review was to summarize the existing knowledge of changes in ICP after mTBI. Literature selection: PubMed, Embase, CINAHL, and Scopus were searched by three reviewers independently up to December 2016. INCLUSION CRITERIA: animal and human studies measuring ICP and brain oedema after an mTBI. EXCLUSION CRITERIA: moderate and severe forms of traumatic brain injury, repeat samples, and studies that measured ICP at the time of impact but not after. Study quality was assessed using Downs and Black criteria. RESULTS: Of 1067 papers, 9 studies were included. In human studies, one provided direct evidence on increased, one provided indirect evidence of increased, and two provided indirect evidence of decreased ICP. In animal studies, three studies provided direct evidence of increased, one provided indirect evidence of increased, and one provided indirect evidence of no change in ICP. CONCLUSION: The existing research suggests that there may be increased ICP after mTBI and animal studies suggest an elevation for days which returns to baseline, which corresponds with functional and symptomatic recovery. Future human studies using sensitive indirect methods to measure ICP longitudinally after mTBI are needed.

Safety and Prognostic Utility of Provocative Exercise Testing in Acutely Concussed Adolescents: A Randomized Trial.

OBJECTIVE: To evaluate (1) systematic assessment of exercise tolerance in adolescents shortly after sport-related concussion (SRC) and (2) the prognostic utility of such assessment. DESIGN: Prospective randomized controlled trial. SETTING: University and community sports medicine centers. PARTICIPANTS: Adolescents with SRC (1-9 days from injury). Sixty-five were randomized and 54 completed the study (mean age 15 years, 4 days after injury). INTERVENTIONS: Buffalo Concussion Treadmill Test (BCTT, n = 27) or not (controls, n = 27) on visit day #1. Heart rate threshold (HRt) at symptom exacerbation represented level of exercise tolerance. Participants reported symptoms daily for 14 days and then had follow-up BCTT (n = 54). Recovery was defined as returning to normal level of symptoms and exercise tolerance, verified by independent physician examination. MAIN OUTCOME MEASURES: Days to recovery and typical (≤21 days) versus prolonged recovery (>21 days). Mixed effects linear models and linear regression techniques examined symptom reports and time to recovery. Linear regression assessed the association of HRt with recovery time. RESULTS: Days to recovery (P = 0.7060) and typical versus prolonged recovery (P = 0.1195) were not significantly different between groups. Symptom severity scores decreased in both groups over 14 days (P < 0.0001), were similar (P = 0.2984), and did not significantly increase the day after the BCTT (P = 0.1960). Lower HRt on visit day #1 was strongly associated with prolonged recovery time (P = 0.0032). CONCLUSIONS: Systematic evaluation of exercise tolerance using the BCTT within 1 week after SRC did not affect recovery. The degree of early exercise intolerance after SRC was important for prognosis. This has implications for school academic and team preparation.

In the wake of a possible mistake: Security motivation, checking behavior, and OCD.

BACKGROUND AND OBJECTIVES: In previous experiments, OCD washers did not differ significantly from controls in their initial level of activation in response to the potential threat of contamination; however, they were less able to reduce their activation by engaging in hand-washing, suggesting that the key problem in OCD is a faulty stopping mechanism. The main objectives of the present experiments were to develop a similar experimental paradigm for investigating checking behavior, and to use it to test the hypothesis that a faulty stopping mechanism also underlies OCD checking. METHODS: Participants sorted pills under the guise of beta testing a new medication system and then were given suggestions of the possibility of having made mistakes with potentially serious consequences. Later, participants engaged in a 90-s checking period and an unlimited period of checking. At baseline and three other times during the experiment, security motivation was measured with respiratory sinus arrhythmia (RSA) and subjective ratings of confidence. Experiment 1 established the parameters of the paradigm in non-patient participants, and Experiment 2 contrasted OCD checkers with OCD washers and non-patients. RESULTS: Results for both subjective and physiological measures of security motivation closely replicated previous findings for washing behavior. Groups did not differ significantly in initial activation, but the OCD checkers were unable to reduce their activation by engaging in period of checking that was ample for returning controls to baseline. LIMITATIONS: The sample size for the patient groups was modest. CONCLUSIONS: These results lend further support to the security-motivation theory of OCD.

When too much is not enough: obsessive-compulsive disorder as a pathology of stopping, rather than starting.

BACKGROUND: In obsessive-compulsive disorder (OCD), individuals feel compelled to repeatedly perform security-related behaviors, even though these behaviours seem excessive and unwarranted to them. The present research investigated two alternative ways of explaining such behavior: (1) a dysfunction of activation--a starting problem--in which the level of excitation in response to stimuli suggesting potential danger is abnormally strong; versus (2) a dysfunction of termination--a stopping problem--in which the satiety-like process for shutting down security-related thoughts and actions is abnormally weak. METHOD: In two experiments, 70 patients with OCD (57 with washing compulsions, 13 with checking compulsions) and 72 controls were exposed to contamination cues--immersing a hand in wet diapers--and later allowed to wash their hands, first limited to 30 s and then for as long as desired. The intensity of activation of security motivation was measured objectively by change in respiratory sinus arrythmia. Subjective ratings (e.g., contamination) and behavioral measures (e.g., duration of hand washing) were also collected. RESULTS: Compared to controls, OCD patients with washing compulsions did not differ significantly in their levels of initial activation to the threat of contamination; however, they were significantly less able to reduce this activation by engaging in the corrective behavior of hand-washing. Further, the deactivating effect of hand-washing in OCD patients with checking compulsions was similar to that for controls, indicating that the dysfunction of termination in OCD is specific to the patient's symptom profile. CONCLUSIONS: These results are the first to show that OCD is characterized by a reduced ability of security-related behavior to terminate motivation evoked by potential danger, rather than a heightened initial sensitivity to potential threat. They lend support to the security-motivation theory of OCD (Szechtman & Woody, 2004) and have important implications both for research into the biological mechanisms underlying OCD and for the development of new treatment approaches.

The psychology of potential threat: properties of the security motivation system.

Results of three experiments support hypothesized properties of the security motivation system, a special motivational system for handling potential threats, as proposed by Szechtman and Woody (2004). First, mild stimuli suggesting potential harm produced a marked state of activation (evident in both objective and subjective measures), consistent with the hypothesis that the security motivation system is finely tuned for the detection of potential threat. Second, in the absence of corrective behavior, this evoked activation is persistent, supporting the hypothesis that once stimulated, the security motivation system produces an enduring motivational state involving the urge to engage in threat-reducing behavior. Third, engagement in corrective behavior was effective in returning activation levels to baseline, whereas cognitive reappraisal was not. These findings are consistent with the hypothesis that deactivation of the security motivation system depends on performance of security-related behaviors, rather than non-behavioral events such as cognitive re-evaluation of threat.