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Background While previous studies have demonstrated a complex visual scene search elicits a robust neurovascular coupling (NVC) response, it is unknown how the duration of visual stimuli presentation influences NVC metrics. This study examined how stimuli duration, in addition to biological sex and self‐reported engagement impact NVC responses. Methods Participants (n = 20, female = 10) completed four visual paradigms. Three involved simple visual shapes presented at 0.5‐, 2‐, and 4‐s intervals in randomized orders. The fourth paradigm was a complex visual scene search (“Where's Waldo?”). Participants completed eight cycles of 20‐s eyes‐closed followed by 40‐s eyes‐open. Transcranial Doppler ultrasound indexed posterior and middle cerebral artery velocities (PCA and MCA). Participants self‐reported their engagement following each task (1 [minimal] to 10 [maximal]). Results The “Where's Waldo?” task evoked greater PCA percent increase (all p, A simple shapes task elicited a modest neurovascular coupling (NVC) response, regardless of image presentation duration (4‐, 2‐, or 0.5‐s). Conversely, a complex “Where's Waldo?” search produced a robust response that maximized the NVC response. While absolute cerebral blood velocity metrics were higher in females, no differences were found between biological sexes regarding the NVC response. However, subjective task engagement had a greater correlation within males, highlighting the need for researchers to use more engaging tasks for males to elicit a similar NVC response compared to females.

Context After concussion, a multifaceted assessment is recommended, including tests of physical exertion. The current criterion standard for exercise testing after concussion is the Buffalo Concussion Treadmill Test (BCTT); however, validated tests that use alternative exercise modalities are lacking. Objective To evaluate the feasibility and concurrent validity of a universal cycling test of exertion compared with the BCTT in adults who sustained a sport-related concussion. Design Crossover study. Setting University sports medicine clinic. Patients or Other Participants Twenty adults (age = 18–60 years) diagnosed with a sport-related concussion. Intervention(s) Participants completed the BCTT and a cycling test of exertion in random order, approximately 48 hours apart. Main Outcome Measure(s) The primary outcome of interest was maximum heart rate (HRmax; beats per minute [bpm]). Secondary outcomes of interest were the total number of symptoms endorsed on the Post-Concussion Symptom Scale, whether the participant reached volitional fatigue (yes or no), the symptom responsible for test cessation (Post-Concussion Symptom Scale), maximum rating of perceived exertion, symptom severity on a visual scale (0–10), and the time to test cessation. Results Of the 20 participants, 19 (10 males, 9 females) completed both tests. One participant did not return for the second test and was excluded from the analysis. No adverse events were reported. The median HRmax for the BCTT (171 bpm; interquartile range = 139–184 bpm) was not different from the median HRmax for the cycle (173 bpm; interquartile range = 160–182 bpm; z = −0.63; P = .53). For both tests, the 3 most frequently reported symptoms responsible for test cessation were headache, dizziness, and pressure in the head. Of interest, most participants (64%) reported a different symptom responsible for cessation of each test. Conclusions On the novel cycling test of exertion, participants achieved similar HRmax and test durations and, therefore, this test may be a suitable alternative to the BCTT. Future research to understand the physiological reason for the heterogeneity in symptoms responsible for test cessation is warranted.

Context Current guidelines for recovery after sport-related concussion (SRC) recommend 24 to 48 hours of rest, followed by a gradual return to activity with heart rate (HR) maintained below the symptom threshold. In addition, monitoring physical activity (PA) after SRC using ActiGraph accelerometers can provide further objective insight into the amounts of activity associated with recovery trajectories. Cutpoint algorithms for these devices allow minute-by-minute PA to be classified into intensity domains; however, researchers have shown that different algorithms used to evaluate the same healthy participant dataset can produce various classifications. Objective To identify the more physiologically appropriate cutpoint algorithm (Evenson or Romanzini) to analyze ActiGraph data among concussed adolescents in comparison with their HR responses on the Buffalo Concussion Treadmill Test (BCTT). Design Prospective cohort study. Setting University sport concussion clinic. Patients or Other Participants Eleven high school students (5 boys, 6 girls; median [range] age = 16 years [15–17 years], height = 177.8 cm [157.5–198.1 cm], mass = 67 kg [52–98 kg], body mass index = 22 [17–31]) involved in high-risk sports who sustained a physician-diagnosed SRC. Main Outcome Measure(s) Evenson and Romanzini algorithm PA intensity domains via ActiGraph data and HR during the BCTT. Results We observed differences in PA time classified as moderate (P = .003) and vigorous (P = .004) intensities between algorithms but no difference in PA time classified as light intensity (P = .48). The Evenson algorithm classified most of the time as moderate-intensity PA (mean = 57.03%, range = 0.00%–94.12%), whereas the Romanzini algorithm classified virtually all PA as vigorous intensity (mean = 88.25%, range = 2.94%–97.06%]). Physical activity based on HR (stages 1–7 = 20%–39% HR reserve [HRR], stages 8–13 = 40%–59% HRR, stages ≥14 = 60%–85% HRR) indicated the BCTT primarily involved light to moderate intensity and, therefore, was better represented by the Evenson algorithm. Conclusions The Evenson algorithm better characterized the HR response during a standardized exercise test in concussed individuals and, thus, should be used to analyze ActiGraph PA data in pediatric populations with concussion.

Objective. Currently, a recording of 300 s is recommended to obtain accurate dynamic cerebral autoregulation estimates using transfer function analysis (TFA). Therefore, this investigation sought to explore the concurrent validity and the within- and between-day reliability of TFA estimates derived from shorter recording durations from squat-stand maneuvers. Approach. Retrospective analyses were performed on 70 young, recreationally active or endurance-trained participants (17 females; age: 26 ± 5 years, [range: 20–39 years]; body mass index: 24 ± 3 kg m−2). Participants performed 300 s of squat-stands at frequencies of 0.05 and 0.10 Hz, where shorter recordings of 60, 120, 180, and 240 s were extracted. Continuous transcranial Doppler ultrasound recordings were taken within the middle and posterior cerebral arteries. Coherence, phase, gain, and normalized gain metrics were derived. Bland–Altman plots with 95% limits of agreement (LOA), repeated measures ANOVA’s, two-tailed paired t-tests, coefficient of variation, Cronbach’s alpha, intraclass correlation coefficients, and linear regressions were conducted. Main results. When examining the concurrent validity across different recording durations, group differences were noted within coherence (F (4155) > 11.6, p F (4155) p > 0.611), gain (F (4155) p > 0.440), or normalized gain (F (4155) p > 0.359) parameters. The Bland–Altman 95% LOA measuring the concurrent validity, trended to narrow as recording duration increased (60 s: Significance. Future studies examining autoregulation should seek to have participants perform 300 s of squat-stand maneuvers. However, valid and reliable TFA estimates can be drawn from 240 s or 180 s recordings if physiological covariates are controlled.

Objectives To identify the symptoms responsible for cessation of exercise testing and evaluate changes in post-concussion symptom scores on the Post-Concussion Symptom Scale (PCSS) from the Sport-Concussion Assessment Tool (SCAT5) immediately, 1-4 hours, and 6-12 hours following completion of the Buffalo Concussion Treadmill Test (BCTT) in youth and adults who have sustained a sport-related concussion. Design Prospective Case-Series. Methods Individuals who were diagnosed with a sport-related concussion and self-reported difficulties with exertion were referred to perform an exertional treadmill test. Individuals were recruited from a university sports medicine clinic. Change in PCSS symptom severity scores were operationally defined as a change ≥4 points. Results Forty-five individuals aged 13-57 years consented to participate. A total of 14/24 (58.3%) female and 13/21 (61.9%) male participants reported an increase in symptom severity scores immediately following the BCTT. At 1-4 hours, 5/10 (50.0%) males and 5/14 (35.7%) females who completed the PCSS had elevated symptom severity scores compared to pre-exertion. Only 24.2% (3/17 males and 5/16 females) of participants completing the PCSS at 6-12 hours reported increased symptom severity scores. Conclusion Exertional testing is an important component of a multifaceted assessment following concussion; however, previous research evaluating symptom responses to exertion is limited. This study provides evidence to suggest individuals who experience an exacerbation of concussion-associated symptoms after exertion are likely to return to pre-exertion levels within the same day. Future research monitoring symptoms following exertion and throughout recovery should be performed in tandem with physiological measures to better understand the source of symptoms.

Introduction One approach to slow the pandemic of obesity and chronic disease is to look to our evolutionary past for clues of the changing behaviors contributing to the emergence of 'diseases of civilization'. Modern humans have deviated from the lifestyle behaviors of our ancestors that have introduced pressures (i.e. diet and activity changes) quicker than our genetic ability to respond. This caused a 'mismatch' between our biological systems and environment, leading to 'man-made' chronic diseases. Purpose The purpose of the study was to investigate the effects of a short-term evolutionarily informed dietary and lifestyle intervention on inflammatory and cardio-metabolic profiles in individuals characterized as having metabolic syndrome (MetS). Methods Twelve subjects with MetS followed a crossover design with two, four-week interventions, including a carbohydrate (CHO)-restricted Paleolithic-based diet (CRPD

Introduction Metabolic syndrome (MetS) has been recognized as one of the most important clinical challenges and global health issues of today. Growing evidence suggests that mechanisms of energy metabolism may also play a key role in mediating aspects of cognitive function. Brain-derived neurotrophic factor (BDNF) is one such factor well known for its critical role in neuronal plasticity, including memory and learning, and more recently metabolic processes. BDNF levels have been shown separately to be dependent on diet and exercise programming. Purpose The purpose of this study was to investigate the effect of diet and exercise on BDNF levels and cognitive functioning with any metabolic association in individuals characterized with MetS. Methods Twelve subjects with MetS followed a randomized crossover design with two four-week interventions, including a carbohydrate (CHO)-restricted Paleolithic-based diet (CRPD

Background: The Sport Concussion Assessment Tool 5 (SCAT5) is a standardized instrument designed to assist with the clinical and sideline assessment of concussion. Following the 5th International Conference on Concussion in Sport in 2016, the SCAT5 was released. Compared to the previous version (SCAT3), the SCAT5 includes more detailed instructions regarding the symptom checklist and a 10-word list in the immediate memory section to diminish ceiling effects. This study aims to examine the association between having a previous history of concussion and SCAT5 scores in high school rugby players. A second objective is to provide reference values for healthy rugby players for the SCAT5, including typical scores on immediate memory using the 10-word list. Methods: High school rugby players (ages 15-18) from Calgary, Alberta participating in the 2018 high school rugby season (n=388, male=212, female=176) were recruited to a cohort study and asked to complete a baseline SCAT5 assessment administered by trained research assistants at the beginning of the playing season. Outcome measures included baseline symptom evaluation (/22 symptoms)], self-reported rating of percentage of normal (100% perfectly normal) felt at time of testing, immediate memory score using a 10-word list [/30)], digits backward (/4), delayed word memory (/10), and modified Balance Error Scoring System [BESS (/30)]. Players also completed a preseason demographic questionnaire, which assessed their history of concussion. Results: A total of 237/388 (61.08%) rugby players reported no history of concussion (NC) and 151/388 (38.92%) reported at least 1 previous concussion (PC). Ninety of the 212 males (42.45%) and 61 of the 176 females (34.66%) reported a history of previous concussion. Median SCAT5 symptom score was 6 (range; 0-21) for NC and 7 (0-22) for PC groups. At the time of baseline testing, only 30.51% of NC players and 21.85% of PC players reported feeling 100% of normal. Median total scores on the immediate memory score (/30) were 21 (range; 9-28) for NC and 21 (range; 9-29) for PC. Median total score on digits backward (/4) was 3 (range; 0-4) and the delayed memory score (/10) was 7 (range; 0-20), for both NC and PC groups. Median total errors made on the BESS were 4 (range; 0-20) for NC players and 5 (range; 0-17) for PC players. Conclusions: Players with and without a previous history of concussion obtained similar scores on all components of the SCAT5 at baseline. Many high school rugby players did not report feeling 100% of normal during typical baseline testing sessions. The addition of the 10-word list option in the immediate and delayed memory section reduces the likelihood of a ceiling effect. This study informs the use and interpretation of the SCAT5 in high school rugby players.