A realistic "dose" of short sleep, similar to what many adolescents experience regularly on school nights, can cause or contribute to symptom reports during concussion assessments. Consistent with previous sleep research, one-on-one cognitive tests seem to be less sensitive than measures of emotional and behavioral functioning to the effects of short sleep.

Autonomic cardiac function can be indirectly detected non-invasively by measuring the variation in microtiming of heart beats by a method known as heart rate variability (HRV). Aerobic training for sport is associated with reduced risk for some factors associated with cardiovascular diseases (CVD), but effects on autonomic function in different athlete types are less known.To compare cardiac autonomic modulation using a standard protocol and established CVD risk factors in highly trained intercollegiate athletes competing in aerobic, explosive, and cross-trained sports. A total of 176 college athletes were categorized in distinct sports as explosive (EA), aerobic (AA), or cross-trained (mixed) athletes. Eight different HRV measures obtained at rest were compared across training type and five health factors: systolic (SBP), diastolic blood pressure (DBP), body weight (BW), sex, and race. All athletic types shared favorable HRV measures that correlated with low CVD risk factors and indicated normal sympathovagal balance. A significant correlation was reported between DBP and pNN50 (% RR intervals > 50 ms) (β = −0.214, p = 0.011) and between BW and low-frequency (LF) power (β = 0.205, p = 0.006). Caucasian and African American athletes differed significantly (p < 0.05) with respect to four HRV variables: pNN50, HF power, LF power, and LF/HF ratios. Explosive, aerobic and mixed athletes had similar cardiovascular and autonomic HRV results in all eight HRV parameters measured. All athletes reported LF and pNN50 values that were significantly correlated with two CVD risk factors: DBP and BW. Compared with Caucasian teammates, African American athletes demonstrated lower LF/HF and higher pNN50, indicating an even more favorable resting sympathovagal activity and healthy CV function.

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Objective: To establish the King-Devick test (KD) performance values for children and adolescents. Design: Prospective cohort. Setting: Pediatric sports medicine clinics. Participants: Five hundred seven athletes presenting to a pediatric sports medicine clinic for non–concussion-related evaluations. Independent Variables: Age, sex, and risk factors for abnormal concussion recovery. Main Outcome Measures: The King-Devick test time. Results: Four hundred eighty-three participants were included in the final analysis, which included 60.5% girls (n = 292) and 39.5% boys (n = 191). The KD test performance varied by age with a steady decrease in test time yearly from 8 years through 14 years of age, where some plateauing occurred. Baseline scores changed approximately 31 seconds over ages 8 to 18. Analysis of variance results revealed a strong effect of age on overall mean KD time (P < 0.001). The KD test performance was not associated with sex or other studied concussion risk factors or comorbid conditions. Conclusions: The KD test performance was reported in a cohort of youth aged 8 to 18 years, allowing for comparison of performance in individuals who may not have a baseline assessment. If baseline testing is desired, at least yearly intervals seems to be appropriate through childhood and early adolescence.

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