Reliability of Computerized Neurocognitive Tests for Concussion Assessment: A Meta-Analysis.

OBJECTIVE: Although widely used, computerized neurocognitive tests (CNTs) have been criticized because of low reliability and poor sensitivity. A systematic review was published summarizing the reliability of Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT) scores; however, this was limited to a single CNT. Expansion of the previous review to include additional CNTs and a meta-analysis is needed. Therefore, our purpose was to analyze reliability data for CNTs using meta-analysis and examine moderating factors that may influence reliability. DATA SOURCES: A systematic literature search (key terms: reliability, computerized neurocognitive test, concussion) of electronic databases (MEDLINE, PubMed, Google Scholar, and SPORTDiscus) was conducted to identify relevant studies. STUDY SELECTION: Studies were included if they met all of the following criteria: used a test-retest design, involved at least 1 CNT, provided sufficient statistical data to allow for effect-size calculation, and were published in English. DATA EXTRACTION: Two independent reviewers investigated each article to assess inclusion criteria. Eighteen studies involving 2674 participants were retained. Intraclass correlation coefficients were extracted to calculate effect sizes and determine overall reliability. The Fisher Z transformation adjusted for sampling error associated with averaging correlations. Moderator analyses were conducted to evaluate the effects of the length of the test-retest interval, intraclass correlation coefficient model selection, participant demographics, and study design on reliability. Heterogeneity was evaluated using the Cochran Q statistic. DATA SYNTHESIS: The proportion of acceptable outcomes was greatest for the Axon Sports CogState Test (75%) and lowest for the ImPACT (25%). Moderator analyses indicated that the type of intraclass correlation coefficient model used significantly influenced effect-size estimates, accounting for 17% of the variation in reliability. CONCLUSIONS: The Axon Sports CogState Test, which has a higher proportion of acceptable outcomes and shorter test duration relative to other CNTs, may be a reliable option; however, future studies are needed to compare the diagnostic accuracy of these instruments.

Injury Rates in Age-Only Versus Age-and-Weight Playing Standard Conditions in American Youth Football.

BACKGROUND: American youth football leagues are typically structured using either age-only (AO) or age-and-weight (AW) playing standard conditions. These playing standard conditions group players by age in the former condition and by a combination of age and weight in the latter condition. However, no study has systematically compared injury risk between these 2 playing standards. PURPOSE: To compare injury rates between youth tackle football players in the AO and AW playing standard conditions. STUDY DESIGN: Cohort study; Level of evidence, 2. METHODS: Athletic trainers evaluated and recorded injuries at each practice and game during the 2012 and 2013 football seasons. Players (age, 5-14 years) were drawn from 13 recreational leagues across 6 states. The sample included 4092 athlete-seasons (AW, 2065; AO, 2027) from 210 teams (AW, 106; O, 104). Injury rate ratios (RRs) with 95% CIs were used to compare the playing standard conditions. Multivariate Poisson regression was used to estimate RRs adjusted for residual effects of age and clustering by team and league. There were 4 endpoints of interest: (1) any injury, (2) non-time loss (NTL) injuries only, (3) time loss (TL) injuries only, and (4) concussions only. RESULTS: Over 2 seasons, the cohort accumulated 1475 injuries and 142,536 athlete-exposures (AEs). The most common injuries were contusions (34.4%), ligament sprains (16.3%), concussions (9.6%), and muscle strains (7.8%). The overall injury rate for both playing standard conditions combined was 10.3 per 1000 AEs (95% CI, 9.8-10.9). The TL injury, NTL injury, and concussion rates in both playing standard conditions combined were 3.1, 7.2, and 1.0 per 1000 AEs, respectively. In multivariate Poisson regression models controlling for age, team, and league, no differences were found between playing standard conditions in the overall injury rate (RRoverall, 1.1; 95% CI, 0.4-2.6). Rates for the other 3 endpoints were also similar (RRNTL, 1.1 [95% CI, 0.4-3.0]; RRTL, 0.9 [95% CI, 0.4-1.9]; RRconcussion, 0.6 [95% CI, 0.3-1.4]). CONCLUSION: For the injury endpoints examined in this study, the injury rates were similar in the AO and AW playing standards. Future research should examine other policies, rules, and behavioral factors that may affect injury risk within youth football.

The minimum number of days required to establish reliable physical activity estimates in children aged 2-15 years.

The purpose of this study was to determine the minimum number of days needed to assess reliable estimates of step-count data for children based on age and gender. A total of 428 developing children (at least 30 boys and 30 girls in seven two-year intervals from 2-3 years to 14-15 years of age) wore a StepWatch accelerometer for 7 consecutive days. Following data screening, the 422 children's data were finally analyzed by age and sex groups using the Generalizability theory. Single-facet crossed designs (i.e. Participant (P) × Days (D)) were applied for each of 14 datasets. G-studies were performed to quantify the percentage of variance associated with the facet and interaction in the model. Follow-up D-studies were performed to determine the minimum number of days of step-count data collection needed to achieve a desirable reliability coefficient (G ≥ 0.80). The results from the G-studies show that P explained a large percentage of the total variance (26-71%) while D had little effect on the total variance (0-5%). A relatively large percentage of variance was unidentified (i.e. the P × D interaction). The minimum number of days necessary to achieve a desirable reliability coefficient (G ≥ 0.80) ranged from 2 to 12 d. On average, boys required less days of monitoring than girls. Researchers should use the findings of this study to design data collection that ensures reliable data.

Objective functional assessment after a head injury using movement and activity in physical space scores: a case report.

OBJECTIVE: To describe the potential benefit of using a global positioning system (GPS) and accelerometry as an objective functional-activity measure after concussion by creating Movement and Activity in Physical Space (MAPS) scores. BACKGROUND: A 21-year-old female soccer player suffered a blow to the back of the head from an opponent's shoulder during an away match. No athletic trainer was present. She played the remainder of the match and reported to the athletic training facility the next day for evaluation. DIFFERENTIAL DIAGNOSIS: Concussion. TREATMENT: The athlete was removed from all athletic activities. Her symptoms were monitored based on the Zurich guidelines. She was also instructed to wear an accelerometer on her hip and to carry an on-person GPS receiver at all times for 10 days. Her total symptom scores for the 4 symptomatic days were 82, 39, 49, and 36. Her mean MAPS functional score for symptomatic days 3 through 5 was 900.9 and for asymptomatic days 6 through 11 was 2734.9. UNIQUENESS: We monitored the patient's function during the concussion-recovery process using an on-person GPS receiver and accelerometer to calculate personalized MAPS scores. This novel approach to measuring function after injury may provide a useful complementary tool to help with return-to-play decisions. CONCLUSIONS: An on-person GPS receiver and accelerometer were used to observe the patient's physical activity in a free-living environment, allowing for an objective measure of function during recovery. Her MAPS scores were low while she was symptomatic and increased as she became asymptomatic. We saw the expected inverse relationship between symptoms and function. In situations where accuracy of reported symptoms may be a concern, this measure may provide a way to verify the validity of, or raise doubts about, self-reported symptoms.

Development of a core-stability model: a delphi approach.

CONTEXT: Despite widespread acceptance, there is currently no consensus on the definition, components, and the specific techniques most appropriate to measure and quantify core stability. OBJECTIVE: To develop a comprehensive core-stability model addressing its definition, components, and assessment techniques. DESIGN: Delphi technique. SETTING: University laboratory. PARTICIPANTS: 15 content experts from United States and Canada, representing a variety of disciplines. MAIN OUTCOME MEASURE: The authors distributed an open-ended questionnaire pertaining to a core-stability definition, components, and assessment techniques specific to each expert. They collected data over 2 rounds of telephone interviews. They concluded data collection once a consensus was achieved that equated with 51% agreement among respondents. RESULTS: The authors developed a working definition of core stability as the ability to achieve and sustain control of the trunk region at rest and during precise movement. Eighty-three percent of the experts considered the definition satisfactory. Therefore, the definition was accepted. Furthermore, the experts agreed that muscles (14/15 = 93.3%) and neuromuscular control (8/12 = 66.7%) were components of core stability. Assessment techniques were identified and inconsistencies were highlighted; however, no consensus was established. CONCLUSIONS: A consensus core-stability definition was created and 2 components were identified. However, of the initial definitions provided by the experts, no 2 were identical, which revealed the inconsistencies among experts and the importance of this study. Nonetheless, the goal of obtaining a consensus definition was obtained. Although a consensus for the assessment techniques of core stability could not be reached, it was a beneficial starting point to identify the inconsistencies that were discovered among the content experts.

Development and validation of a movement and activity in physical space score as a functional outcome measure.

OBJECTIVE: To develop and validate a functional measure, the Movement and Activity in Physical Space (MAPS) score, that encompasses both physical activity and environmental interaction. DESIGN: Observational matched-pair cohort with 2-month follow-up. SETTING: General community under free-living conditions. PARTICIPANTS: Adult participants (N=18; n=9 postsurgical, n=9 matched control; mean age ± SD, 28.9 ± 12.0y) were monitored by an accelerometer and global positioning system receiver for 3 days within 1 week (4.1 ± 2.8d) after knee surgery (T=0) and 2 months later (T+2). The healthy controls were matched for age, sex, smoking, perceived physical activity level, and occupation of a postsurgical participant. Correlation, t test (with Bonferroni adjustment: α=.05/2), analysis of variance, and intraclass correlation coefficient were used to establish validity and reliability evidence. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURE: MAPS scores. RESULTS: MAPS scores were moderately correlated with the Knee Injury and Osteoarthritis Outcome Score (P<.05). There was a significant group difference at T = 0 for MAPS (t(9.9)=-3.60; P=.01). Analysis of variance results for the MAPS indicated a time and group interaction (F(1,12)=4.60, P=.05). Reliability of 3 days of MAPS scores ranged from 0.75 to 0.81 (postsurgical and control), and 2-month test-retest reliability in the control group was 0.94. CONCLUSIONS: The results provide a foundation of convergent and known-group difference validity evidence along with reliability evidence for the use of MAPS as a functional outcome measure.

Effects of exercise training on dendritic morphology in the cardiorespiratory and locomotor centers of the mature rat brain.

It has been shown that dendritic branching in neural cardiorespiratory and locomotor centers can be attenuated with exercise training (ET) initiated immediately after weaning. The purpose of this study was to determine whether neuroplastic changes occur within cardiorespiratory and locomotor centers due to ET after maturation. Male Sprague-Dawley rats (21 days old, n=28) were individually housed in standard cages. At 91 days of age, animals were divided into two groups: untrained (UN; n=14) and trained (TR; n=14). The TR group exercised spontaneously for 50 days on running wheels. ET indexes were obtained, including maximal O2 consumption, percent body fat, resting heart rate, and heart weight-to-body weight ratios. The brain was processed with a modified Golgi-Cox procedure. Impregnated neurons from the periaqueductal gray (PAG), posterior hypothalamic area (PH), nucleus of the tractus solitarius (NTS), cuneiform nucleus (CnF), rostral ventrolateral medulla, nucleus cuneatus, and cerebral cortex were examined. Neurons were traced and analyzed using the Sholl concentric ring analysis of dendritic branching. The mean total number of dendritic intersections with the concentric rings per neuron per animal were compared between UN and TR groups. There were significant differences between UN and TR groups in the PH, PAG, CnF, and NTS in the total number of intersections per animal. In some areas, the effect size was smaller when ET was initiated in mature animals, possibly related to their relatively reduced activity levels. In conclusion, the adult rat brain remains dynamic and adapts to chronic ET. However, some brain areas appear to be more affected if ET is initiated in early postnatal development.

Measuring practice capacity for change: a tool for guiding quality improvement in primary care settings.

PURPOSE: Capacity for change, or the ability and willingness to undertake change, is an organizational characteristic with potential to foster quality management in health care. We report on the development and psychometric properties of a quantitative measure of capacity for change for use in primary care settings. METHODS: Following review of previous conceptual and empirical studies, we generated 117 items that assessed organizational structure, climate, and culture. Using information from direct observation and key informant interviews, a research team member rated these items for 15 primary care practices engaged in a quality improvement intervention. Distributional statistics, pairwise correlation analysis, Rasch modeling, and item content review guided item reduction and instrument finalization. Reliability and convergent validity were assessed. RESULTS: Ninety-two items were removed because of limited response distributions and redundancy or because of poor Rasch model fit. The final instrument comprising 25 items had excellent reliability (alpha = .94). A Rasch model-derived capacity for change score correlated well with an independently determined, qualitatively derived summary assessment of each practice's capacity for change (rhoS = 0.82), suggesting good convergent validity. CONCLUSION: We describe a new instrument for quantifying organizational capacity for change in primary care settings. The ability to quantify capacity for change may enable better recognition of practices likely to be successful in their change efforts and those first requiring capacity building prior to change interventions.

How many days was that? We're still not sure, but we're asking the question better!

Unreliable measures limit the ability to detect relationships with other variables. Day-to-day variability in measurement is a source of unreliability. Studies vary substantially in numbers of days needed to reliably assess physical activity. The required numbers of days has probably been underestimated due to violations of the assumption of compound symmetry in using the intraclass correlation. Collecting many days of data become unfeasible in real-world situations. The current dilemma could be solved by adopting distribution correction techniques from nutrition or gaining more information on the measurement model with generalizability studies. This would partition the variance into sources of error that could be minimized. More precise estimates of numbers of days to reliably assess physical activity will likely vary by purpose of the study, type of instrument, and characteristics of the sample. This work remains to be done.

Development of the mental, emotional, and bodily toughness inventory in collegiate athletes and nonathletes.

CONTEXT: The assessment of an individual's mental toughness would assist clinicians in enhancing an individual's performance, improving compliance with the rehabilitation program, and improving the individual treatment program. However, no sound measure of mental toughness exists. OBJECTIVE: To develop a new measure of mental toughness, the Mental, Emotional, and Bodily Toughness Inventory (MeBTough). DESIGN: Participants were invited to complete a 45-item questionnaire. SETTING: University research laboratory. PATIENTS OR OTHER PARTICIPANTS: A total of 261 undergraduate students were recruited to complete the questionnaire. MAIN OUTCOME MEASURE(S): The Rasch-calibrated item difficulties, fit statistics, and persons' mental toughness ability estimates were examined for model-data fit of the MeBTough. RESULTS: Forty-three of the 45 items had good model-data fit with acceptable fit statistics. Results indicated that the distribution of items was fittingly targeted to the people and the collapsed rating scale functioned well. The item separation index (6.31) and separation reliability statistic (.98) provided evidence that the items had good variability with a high degree of confidence in replicating placement of the items from another sample. CONCLUSIONS: Results provided support for using the new measure of mental, emotional, and bodily toughness.

Issues in outcomes research: an overview of randomization techniques for clinical trials.

OBJECTIVE: To review and describe randomization techniques used in clinical trials, including simple, block, stratified, and covariate adaptive techniques. BACKGROUND: Clinical trials are required to establish treatment efficacy of many athletic training procedures. In the past, we have relied on evidence of questionable scientific merit to aid the determination of treatment choices. Interest in evidence-based practice is growing rapidly within the athletic training profession, placing greater emphasis on the importance of well-conducted clinical trials. One critical component of clinical trials that strengthens results is random assignment of participants to control and treatment groups. Although randomization appears to be a simple concept, issues of balancing sample sizes and controlling the influence of covariates a priori are important. Various techniques have been developed to account for these issues, including block, stratified randomization, and covariate adaptive techniques. ADVANTAGES: Athletic training researchers and scholarly clinicians can use the information presented in this article to better conduct and interpret the results of clinical trials. Implementing these techniques will increase the power and validity of findings of athletic medicine clinical trials, which will ultimately improve the quality of care provided.

Generalizability of Stabilogram Diffusion Analysis of center of pressure measures.

Quiet standing balance and postural control are often assessed by drawing information from center of pressure (COP) data collected with a force platform. Efforts to better understand the underlying processes involved in postural control have lead to methods that examine the dynamic or stochastic characteristics of the COP. One method that has recently gained popularity is Stabilogram Diffusion Analysis (SDA). There is, however, a lack of standardization in the methodology of data collection for this approach, i.e., how many trials to include and how long to sample a trial. The purpose of this study was to use the tools of Generalizability Theory (G-Theory) to investigate the reliability of SDA measures of quiet standing and to establish an optimal measurement protocol. G-Theory provides a tool that allows us to break down the sources of variation, or facets, in a measurement procedure and ultimately design a protocol that provides optimal reliability. Fifteen young, healthy participants completed ten 90-s trials: first with eyes open and then eyes closed. Common measures of SDA were calculated using the first 30, 60 and 90 s of each trial. G-Theory through a Generalizability Study (G-study) and follow-up Decision Studies (D-studies) were performed to estimate reliability coefficients (G-coefficients). The fully crossed facets included were participants (P), length of trials (L) and number of trials (T). Results of this study suggest that at least five 60s trials should be used when using the selected measures of SDA. These guidelines address acceptable reliability and the gains achieved by adding trials or increasing trial length.

Salicylate-based analgesic balm attenuates pressor responses from skeletal muscle.

PURPOSE: Analgesic balms (AB) are widely used in sports medicine. We previously have examined effects of various counterirritant-based AB on pressor responses evoked by muscular contraction (MC), mediated by group III and IV muscle afferents known to produce exercise and nociceptive responses. Our purpose was to examine trolamine salicylate-based analgesic balm (TS) effects. METHODS: Ten healthy, adult male and female cats were used. Decerebration under halothane allowed elimination of anesthesia. Electrical stimulation of L7 and S1 ventral roots evoked static MC (30 s). After control runs, commercial TS (10% concentration) was applied to the skin over the contracting muscles of one hind limb (N = 5). MC was evoked every 10 min, alternating between sides. Ipsilateral (T = 0, T + 20, T + 40, T + 60 min) and contralateral (T - 10, T + 10, T + 30, T + 50 min) responses were analyzed. Five additional cats received AB minus TS. RESULTS: There were significant attenuations in both peak mean arterial pressure (MAP), in the last 12 s and the last 6 s of the 30 s of MC for both contra- and ipsilateral limbs occurring at T + 50 and T + 60 min after TS application, respectively. No significant changes in heart rate (HR) responses were seen for either the ipsi- or contralateral stimulation. There were no changes in MAP or HR in control cats. CONCLUSIONS: These results indicate that TS affects the end of the 30 s of MC, which is thought to be mainly chemically mediated through group IV afferents. TS represents the salicylate class of AB and has no counterirritant properties. TS works as an inhibitor of cyclooxygenase (prostaglandin formation) and is, at least in part, blood borne.

Generalizability of center of pressure measures of quiet standing.

Center of pressure (COP) measures are commonly used as indicators of balance and postural control. At present, there are no universally accepted standards in research investigating fluctuations in the COP with regard to the number of trials or the length of a given trial. The purpose of this study was to use the tools of Generalizability Theory (G-Theory) to investigate the reliability of COP measures of quiet standing and to establish an optimal measurement protocol. G-Theory provides a tool that allows us to break down the sources of variation, or facets, in a measurement procedure and ultimately design a protocol that provides optimal reliability. Fifteen participants completed 10 90-s trials with eyes open and closed. COP measures of anterior-posterior standard deviation (SD(AP)), medial-lateral SD (SD(ML)), average velocity (Vel), and 95% confidence ellipse area (Area) were calculated using the first 30, 60, and 90s of each trial. A G-study and follow-up D-studies were performed to estimate reliability coefficients (G-coefficients). The results of the G-Theory analysis suggest that these COP measures reached acceptable levels of reliability (G>or=0.70) with at least five 60s trials.

Effects of a menthol-based analgesic balm on pressor responses evoked from muscle afferents in cats.

OBJECTIVE: To evaluate changes in heart rate (HR) and mean arterial pressure (MAP) as indicators of changes in pressor response for muscle afferents after topical application of menthol (MEN)-based analgesic balm. ANIMALS: 11 decerebrate cats. PROCEDURE: Pressor responses were reflexively evoked by static contraction of hind limb muscles, which are caused by group III and IV afferents. Responses were monitored without interference from anesthesia or effects of higher brain function by the use of decerebrate cats. After obtaining baseline data, MEN analgesic balm (1.9%) was applied to the skin over contracting muscles of 1 hind limb in 6 cats; petrolatum was applied to 5 control cats. Muscle contractions were evoked every 10 minutes, alternating between hind limbs, for 120 minutes. Peak MAP and HR were analyzed. RESULTS: Peak MAP responses evoked by static muscle contraction for the ipsilateral hind limb were significantly attenuated 20 minutes after application, but approached baseline values 40 minutes after application. The pressor response was significantly decreased 20 minutes after application during the last 12 seconds of the stimulus, which was attributed to group IV afferents. There were no significant differences in HR responses. CONCLUSIONS AND CLINICAL RELEVANCE: Application of MEN analgesic balm to the skin over contracting muscles significantly decreased the pressor response to static muscle contractions. This suggests that topical application of MEN has effects on responses evoked from receptors located in muscles. The MEN analgesic balm appeared to attenuate the pressor response 20 minutes after application, but it was a short-term effect.

Capsaicin-based analgesic balm decreases pressor responses evoked by muscle afferents.

UNLABELLED: Capsaicin-based analgesic balm decreases pressor responses evoked by muscle afferents. Physically active individuals use countless analgesic balm (AB) products with various active ingredients daily. Despite this, few studies have investigated the mechanism of action and efficacy of AB. PURPOSE: We examined the effects of capsaicin (CAP) application on pressor responses evoked by muscle contraction (MC), which are mediated by group III and IV muscle afferents. METHODS: Heart rate (HR), blood pressure, and end-tidal CO2 were monitored in cats (N = 12) decerebrated under halothane. Decerebration eliminated anesthesia use and effects from the higher brain. Electrical stimulation of L7 and S1 ventral roots evoked static hindlimb MC (30 s). After control runs, a commercial CAP (4.95% Oleoresin Capsicum) AB was applied to the skin over the contracting muscles of one hindlimb. MC were evoked every 10 min, alternating between hindlimbs. Data were analyzed with RM ANOVA and Tukey post hoc test. RESULTS: Changes in peak mean arterial pressure (MAP) induced by static ipsilateral MC were significantly attenuated at 20 min and tended to approach baseline levels at 40 min after CAP application. The mean (+/- SEM) of the peak MAP for the ipsilateral side just before application (T = 0), at 20 min (T+20), and 40 min (T+40) were 28.3 mm Hg +/- 6.4, 13.8 mm Hg +/-2.9, and 22.6 mm Hg +/- 5.2, respectively. There were no significant changes in HR. CONCLUSIONS: Cardiovascular effects due to activation of group III and IV afferent fibers were significantly attenuated by the application of CAP. The time course of the effects appeared to support the need for repeated CAP application for pain relief. Central nervous system circuitry responsible for this effect awaits elucidation.

Effects of topical analgesics on the pressor response evoked by muscle afferents.

PURPOSE: Pressor responses are reflexly evoked by the activation of groups III and IV muscle afferents, which are also known to mediate nociceptive responses. In this experiment, the effects of analgesic balm (AB) application on these responses were investigated without the interference of other types of anesthesia or effects from the higher brain. METHODS: Heart rate (HR), blood pressure, and end-tidal CO(2) were monitored in midcollicularly decerebrated cats. Static contractions (30 s) of hindlimb muscles were evoked by electric stimulation of L7 and S1 ventral roots. After control runs, a commercial AB (1% capsaicin, 12.5% methyl salicylate) was applied to the skin surface over the contracting muscles. Muscle contractions were evoked every 10 min, alternating between the two hindlimbs. RESULTS: Changes in mean arterial pressure (MAP) evoked by static ipsilateral muscular contraction were significantly attenuated 20 min and 40 min after AB application. The decreases in the pressor response were significant at both the initial and the last parts of the stimulus intervention after 20 min of AB application. There were no significant changes in the response to contraction of the hindlimb contralateral to the AB application. Application of AB to the contralateral leg did not add to the ipsilateral effects. CONCLUSIONS: AB application to the skin surface over contracting muscles significantly decreased autonomic responses to static muscular contraction. This effect was independent of higher cortical processing and strongly suggests that application of methyl salicylate and capsaicin on the skin has analgesic effects on signals from receptors located in muscle.