Objectives: Osteopathic manipulative treatment (OMT) focused on the upper cervical spine is theorized to affect the function of the vagus nerve and thereby influence the parasympathetic branch of the autonomic nervous system. This study was designed to determine the acute effect of upper cervical spine manipulation on cardiac autonomic control as measured by heart rate variability. Design: Nineteen healthy, young adult subjects underwent three different experimental interventions administered in random order: cervical OMT, sham manipulation, and time control. Six minutes of electrocardiographic data were collected before and after each intervention, and heart rate variability was assessed by both time-domain and frequency-domain measures. Results: No differences in resting heart rate or any measure of heart rate variability were observed between the baseline periods prior to each intervention. The OMT protocol resulted in an increase in the standard deviation of the normal-to-normal intervals (0.12 -0.082 seconds, p < 0.01), an increase in the high frequency spectral power ( p = 0.03), and a decrease in the low/high frequency spectral ratio ( p = 0.01) relative to the sham and time control conditions. No significant differences between sham and time control were observed ( p > 0.11 for all variables). Conclusions: These data support the hypothesis that upper cervical spine manipulation can acutely affect measures of heart rate variability in healthy individuals.

An overground walking program appears to offer some advantages over a treadmill walking program in older adults. Using RPE alone to regulate intensity may reduce the benefits of a treadmill walking program in older adults.

IMPORTANCE The Four Corners Youth Consortium was created to fill the gap in our understanding of youth concussion. This study is the first analysis of posttraumatic headache (PTH) phenotype and prognosis in this cohort of concussed youth. OBJECTIVE To describe the characteristics of youth with PTH and determine whether the PTH phenotype is associated with outcome. DESIGN, SETTING, AND PARTICIPANTS This cohort study examined outcomes from patients in a multi-institutional registry of traumatic brain injury (TBI) clinics from December 2017 to June 2019. Inclusion criteria included being between ages 5 and 18 years at enrollment and presentation within 8 weeks of a mild TBI. Data were analyzed between February 2019 and January 2021. EXPOSURE Mild TBI with standard care. MAIN OUTCOMES AND MEASURES Time to recovery and headache 3 months after injury; measurement device is the Postconcussion Symptom Inventory (PCSI). PTH with migraine phenotype was defined as moderate-severe headache that is new or significantly worse compared with baseline and associated with nausea and/or photophobia and phonophobia. RESULTS A total of 612 patients with 625 concussions were enrolled, of whom 387 patients with 395 concussions consented to participate in this study. One hundred nine concussions were excluded (concussions, rather than patients, were the unit of analysis), leaving 281 participants with 286 concussions (168 [58.7%] girls; 195 [75.6%] White; 238 [83.2%] aged 13-18 years). At the initial visit, 133 concussions (46.5%) were from patients experiencing PTH with a migraine phenotype, 57 (20%) were from patients experiencing PTH with a nonmigraine phenotype, and 96 (34%) were from patients with no PTH. Patients with any PTH after concussion were more likely to have prolonged recovery than those without PTH (median [interquartile range], 89 [48-165] days vs 44 [26-96] days; log-rank P < .001). Patients with PTH and a migraine phenotype took significantly longer to recover than those with nonmigraine phenotype (median [interquartile range], 95 [54-195] days vs 70 [46-119] days; log-rank P = .01). Within each phenotype, there was no significant difference between sexes in recovery or PTH at 3 months.

IMPORTANCEPediatric mild traumatic brain injury (TBI) and concussion are a public health challenge with up to 30% of patients experiencing prolonged recovery. Pediatric patients presenting to concussion clinics often have ongoing impairments and may be at increased risk for persistent symptoms. Understanding this population is critical for improved prognostic estimates and optimal treatment. OBJECTIVE To describe pediatric patients presenting to concussion clinics and characterize factors associated with their recovery. DESIGN, SETTING, AND PARTICIPANTS This prospective cohort study included patients enrolled at multicenter concussion specialty clinics from the Four Corners Youth Consortium from December 2017 to July 2019, with up to 12-month follow-up. Patients were eligible if they were aged 5 to 18.99 years with a diagnosis of mild TBI or concussion presenting to participating clinics within 8 weeks of injury. Patients were excluded if the patient or their parents were unable to read or sign the consent document, or if the patient had a Glasgow Coma Scale score less than 13 or a penetrating injury. Data were analyzed from February 2019 to April 2020. EXPOSURES Diagnosis of mild TBI or concussion. MAIN OUTCOMES AND MEASURES This study used National Institute of Neurological Disorders and Stroke common data elements, including data on demographic characteristics, injury details, history, neurological and neuropsychological assessments, and treatment. RESULTS A total of 600 patients were consecutively enrolled, among whom 324 (54.0%) were female and 435 (72.5%) were adolescents (ie, aged 13-18 years). A higher proportion of girls and women (248 patients [76.5%]) were adolescents compared with boys and men (187 patients [67.8%]) (P = .02), and girls and women reported significantly more preexisting anxiety compared with boys and men (80 patients [26.7%] vs 46 patients [18.7%]; P = .03). Significantly more adolescents reported preexisting migraines compared with preadolescents (82 patients [20.9%] vs 15 patients [10.9%]; P = .01). Girls and women recovered more slowly than boys and men (persistent symptoms after injury: week 4, 217 patients [81.6%] vs 156 patients [71.2%]; week 8, 146 patients [58.9%] vs 89 patients [44.3%]; week 12, 103 patients [42.6%] vs 58 patients [30.2%]; P = .01). Patients with history of migraine or anxiety or depression recovered more slowly than those without, regardless of sex.(continued) Key Points Question What factors are associated with recovery in pediatric patients with mild traumatic brain injury or concussion? Findings In this cohort study of 600 pediatric patients presenting to concussion clinics in 3 centers, girls and women experienced slower recovery and were more likely to have preexisting anxiety compared with boys and men. Independent of sex, patients with anxiety or depression or migraine recovered more slowly than those without these comorbidities. Meaning These findings suggest that factors, such as sex and comorbidities, in pediatric patients with mild traumatic brain ...

The link between sleep apnoea and systemic hypertension in humans is well documented. However, a direct causal association between the two diseases independent of comorbidities has been difficult to establish. Comorbidities clearly play an important role in this strong relationship; however, new findings also suggest that sleep apnoea is an independent risk factor for hypertension. This relationship appears to be at least in part a result of chronically elevated sympathetic activity, and therefore manifests as a neurally mediated hypertension. Although the mechanism(s) for this causal relationship of sleep apnoea to hypertension remains ill defined, a growing body of literature suggests that autonomic dysfunction, mediated by abnormal chemoreflex control of sympathetic activity, is a potential mechanism. Abnormal chemoreflex responses to both acute and chronic apnoea or hypoxia have been demonstrated. Hypothesized mechanisms by which chemoreflex dysfunction may contribute to chronically elevated sympathetic tone and ultimately hypertension are explored in this review. Thus, this review focuses on the current evidence linking chemoreflex function to obstructive sleep apnoea and systemic hypertension in humans and provides an analysis of these data and their implications. The link between obstructive sleep apnoea (OSA) and cardiovascular morbidity, particularly systemic hypertension, is well recognized. However, a true causal relationship, independent of common comorbidities (such as obesity, metabolic disorders, etc.), has been difficult to demonstrate. In 2000, Peppard and colleagues demonstrated in a longitudinal study a dose-dependent relationship between the severity of sleep apnoea and subsequent development of hypertension (Peppard et al. 2000). Moreover, these data suggest that this relationship was independent of comorbidity and other confounding factors. These findings are the first to directly implicate sleep apnoea as causative for the occurrence of hypertension. The physiological mechanism(s) responsible for this direct causal association of sleep apnoea to hypertension remains elusive. A growing body of evidence points to autonomic dysfunction and abnormal vascular control as the primary culprits, and this is the focus of this themed issue of Experimental Physiology. In this review, a case is made for abnormal chemoreflex control of sympathetic activity as the primary mechanism driving the increased risk of neurogenicmediated hypertension accompanying sleep apnoea.In patients with chronic OSA, there are significant elevations of production and circulation of catecholamines during sleep and wakefulness (Fletcher et al. 1987;Carlson et al. 1993;Marrone et al. 1993;Somers et al. 1995;Garcia-Rio et al. 2000). Marrone et al. (1993) illustrated that both noradrenaline and adrenaline were elevated in patients with sleep apnoea and that urinary adrenaline secretion decreased in the absence of apnoeas. Fletcher et al. (1987) and Carlson et al. (1993) both demonstrated elevated noradrenaline levels in OSA pati...