Short sleep duration and health outcomes: a systematic review,meta-analysis,and meta-regression

ObjectiveThe dose–response of short sleep duration in mortality has been studied, in addition to the incidences of notable health complications and diseases such as diabetes mellitus, hypertension, cardiovascular diseases, stroke, coronary heart diseases, obesity, depression, and dyslipidemia.MethodsWe collected data from prospective cohort studies with follow-ups of one year or more on associations between short sleep duration and the outcomes. For the independent variable, we divided participants at baseline into short sleepers and normal sleepers. The primary outcomes were defined as mortality and an incident of each health outcome in the long-term follow-up. Risk ratios (RRs) for each outcome were calculated through meta-analyses of adjusted data from individual studies. Sub-group and meta-regression analyses were performed to investigate the association between each outcome and the duration of short sleep.ResultsData from a cumulative total of 5,172,710 participants were collected from 153 studies. Short sleep was significantly associated with the mortality outcome (RR, 1.12; 95% CI, 1.08–1.16). Similar significant results were observed in diabetes mellitus (1.37, 1.22–1.53), hypertension (1.17, 1.09–1.26), cardiovascular diseases (1.16, 1.10–1.23), coronary heart diseases (1.26, 1.15–1.38), and obesity (1.38, 1.25–1.53). There was no sufficient usable evidence for meta-analyses in depression and dyslipidemia. Meta-regression analyses found a linear association between a statistically significant increase in mortality and sleep duration at less than six hours. No dose–response was identified in the other outcomes.ConclusionsBased on our findings, future studies should examine the effectiveness of psychosocial interventions to improve sleep on reducing these health outcomes in general community settings.     

Zinc transporter 3 (ZnT3) and vesicular zinc in central nervous system function

Zinc transporter 3 (ZnT3) is the sole mechanism responsible for concentrating zinc ions within synaptic vesicles in a subset of the brain’s glutamatergic neurons. This vesicular zinc can then be released into the synaptic cleft in an activity-dependent fashion, where it can exert many signaling functions. This review provides a comprehensive discussion of the localization and function of ZnT3 and vesicular zinc in the central nervous system. We begin by reviewing the fundamentals of zinc homeostasis and transport, and the discovery of ZnT3. We then focus on four main topics. I) The anatomy of the zincergic system, including its development and its modulation through experience-dependent plasticity. II) The role of zinc in intracellular signaling, with a focus on how zinc affects neurotransmitter receptors and synaptic plasticity. III) The behavioural characterization of the ZnT3 KO mouse, which lacks ZnT3 and, therefore, vesicular zinc. IV) The roles of ZnT3 and vesicular zinc in health and disease.     

Concurrent insomnia and habitual snoring are associated with adverse pregnancy outcomes

ObjectivesPregnant women report disturbed sleep, including habitual snoring and insomnia. The co-occurrence among non-pregnant cohorts is 30%–50% with increased risk for adverse health outcomes. To date, no study has examined the comorbid status or impact in pregnant women.MethodsThe prevalence of insomnia (INS) and habitual snoring (HS) were examined in 439 women in the third trimester (34.1 ± 3.7 weeks). Habitual snoring (snoring ≥3 times/week) was self-reported. Insomnia was determined using the Insomnia Symptom Questionnaire (ISQ).ResultsFour groups emerged: HS−/ISQ− (n = 161; 36.7%), HS−/ISQ+ (n = 146; 33.3%), HS+/ISQ− (n = 63; 14.4%), and HS+/ISQ+ (n = 69; 15.7%). Logistic regression models revealed both independent associations, as well as comorbid HS/INS status with excessive daytime sleepiness (aOR 3.8, 95%CI 2.3–6.5, p < 0.001; aOR 2.2, 95%CI 1.1–4.4, p = 0.02; aOR 7.2, 95%CI 3.7–14.0, p < 0.001, respectively). Only comorbid HS/INS was associated with gestational hypertension (aOR 3.2 95%CI 1.0–10.6, p = 0.048). Insomnia alone and HS alone were associated with a baby born large for gestational age (aOR 2.9 95%CI 1.2–7.1, p = 0.019 and aOR 3.5, 95%CI 1.1–11.1, p = 0.034 respectively) but however, the comorbid state was not significantly associated with LGA. Only women with HS alone were at increased odds of having an unplanned cesarean section (aOR 2.2 95%CI 1.0–4.6, p = 0.046).ConclusionsBoth insomnia alone and comorbid insomnia/habitual snoring were associated with adverse outcomes even after accounting for confounders. These findings are clinically relevant since adverse pregnancy outcomes may have severe consequences for both mother and baby. In order to mitigate these outcomes, identifying viable treatment(s) for women at risk should be considered a high priority.     

Effects of methylmercury on spinal cord afferents and efferents—A review

Methylmercury (MeHg) is an environmental neurotoxicant of public health concern. It readily accumulates in exposed humans, primarily in neuronal tissue. Exposure to MeHg, either acutely or chronically, causes severe neuronal dysfunction in the central nervous system and spinal neurons; dysfunction of susceptible neuronal populations results in neurodegeneration, at least in part through Ca²⁺-mediated pathways. Biochemical and morphologic changes in peripheral neurons precede those in central brain regions, despite the fact that MeHg readily crosses the blood-brain barrier. Consequently, it is suggested that unique characteristics of spinal cord afferents and efferents could heighten their susceptibility to MeHg toxicity. Transient receptor potential (TRP) ion channels are a class of Ca²⁺-permeable cation channels that are highly expressed in spinal afferents, among other sensory and visceral organs. These channels can be activated in numerous ways, including directly via chemical irritants or indirectly via Ca²⁺ release from intracellular storage organelles. Early studies demonstrated that MeHg interacts with heterologous TRP channels, though definitive mechanisms of MeHg toxicity on sensory neurons may involve more complex interaction with, and among, differentially-expressed TRP populations. In spinal efferents, glutamate receptors of the N-methyl-D-aspartate (NMDA), α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA), and possibly kainic acid (KA) classes are thought to play a major role in MeHg-induced neurotoxicity. Specifically, the Ca²⁺-permeable AMPA receptors, which are abundant in motor neurons, have been identified as being involved in MeHg-induced neurotoxicity. In this review, we will describe the mechanisms that could contribute to MeHg-induced spinal cord afferent and efferent neuronal degeneration, including the possible mediators, such as uniquely expressed Ca²⁺-permeable ion channels.     

Molecular regulation of dendritic spine dynamics and their potential impact on synaptic plasticity and neurological diseases

The structure and dynamics of dendritic spines reflect the strength of synapses, which are severely affected in different brain diseases. Therefore, understanding the ultra-structure, molecular signaling mechanism(s) regulating dendritic spine dynamics is crucial. Although, since last century, dynamics of spine have been explored by several investigators in different neurological diseases, but despite countless efforts, a comprehensive understanding of the fundamental etiology and molecular signaling pathways involved in spine pathology is lacking. The purpose of this review is to provide a contextual framework of our current understanding of the molecular mechanisms of dendritic spine signaling, as well as their potential impact on different neurodegenerative and psychiatric diseases, as a format for highlighting some commonalities in function, as well as providing a format for new insights and perspectives into this critical area of research. Additionally, the potential strategies to restore spine structure–function in different diseases are also pointed out. Overall, these informations should help researchers to design new drugs to restore the structure–function of dendritic spine, a “hot site” of synaptic plasticity.     

Quality of life for parents of children with autism spectrum disorders

This project describes health-related quality of life (HRQoL) of parents of children with autism spectrum disorders (ASDs) using mixed methods. Parents of children with ASDs (N = 224) reported on their HRQoL, depression, and caregiving burden using quantitative tools. HRQoL scores were slightly worse than from those in normative populations especially related to stress and mental health. For example, parents reported average HRQoL scores from SF-6D of 0.74, which was clinically significant lower than an average normative U.S. population. 40% of parents reported having clinical depression symptoms. Married parents reported lower depression symptoms than parents who were not. In addition, families with three or more children with special health care needs (CSHCN) reported lower HRQL and higher caregiving burden than families with less CSHCN. In the qualitative study, we conducted five focus groups to gain insight as to the reasons a child's ASD might influence a parent's HRQoL. Qualitative data further supports the notion that parental HRQoL was negatively influenced by their child's ASDs. Studies that seek to quantify the influence of ASDs and to assess the effect of interventions for children with ASDs may consider measuring the effects on family members as well.     

Epigenetics of stress adaptations in the brain

Recent findings in epigenetics shed new light on the regulation of gene expression in the central nervous system (CNS) during stress. The most frequently studied epigenetic mechanisms are DNA methylation, histone modifications and microRNA activity. These mechanisms stably determine cell phenotype but can also be responsible for dynamic molecular adaptations of the CNS to stressors. The limbic–hypothalamic–pituitary–adrenal axis (LHPA) is the primary circuit that initiates, regulates and terminates a stress response. The same brain areas that control stress also react to stress dynamically and with long-term consequences. One of the biological processes evoking potent adaptive changes in the CNS such as changes in behavior, gene activity or synaptic plasticity in the hippocampus is psychogenic stress. This review summarizes the current data regarding the epigenetic basis of molecular adaptations in the brain including genome-wide epigenetic changes of DNA methylation and particular genes involved in epigenetic responses that participate in the brain response to chronic psychogenic stressors. It is concluded that specific epigenetic mechanisms in the CNS are involved in the stress response.     

Long term retention of retigabine in a cohort of people with drug resistant epilepsy

PurposeTo assess the utility of retigabine (RTG) for epilepsy in clinical practice at a single UK tertiary centre.MethodsWe identified all individuals who were offered RTG from April 2011 to May 2013. We collected demographics, seizure types, previous and current antiepileptic drugs (AEDs), starting and maximum attained daily dose of RTG, clinical benefits, side effects, and reason to discontinue RTG from in- and outpatient encounters until February 28, 2014.Results145 people who had failed a median of 11 AEDs took at least one dose of RTG. One year retention was 32% and decreased following the safety alert by the US Federal Drug Administration (FDA) in April 2013. None became seizure free. 34 people (24%) reported a benefit that was ongoing at last assessment in five (3%). The most relevant benefit was the significant reduction or cessation of drop attacks or seizure-related falls in four women, this persisted at last assessment in two. The presence of simple partial seizures was associated with longer retention, as was a higher attained dose of RTG. Adverse effects were seen in 74% and largely CNS-related or nonspecific and affected the genitourinary system in 13%.ConclusionRetention of RTG was less favourable compared to data from open label extension studies of the regulatory trials. In comparison with historical data on similar retention audits retention of RTG at one year appears to be less than lamotrigine, topiramate, levetiracetam, pregabalin, zonisamide, and lacosamide, and slightly higher than gabapentin.     

Awareness and knowledge of obstructive sleep apnea among the general population

BackgroundObstructive sleep apnea (OSA) is an increasingly prevalent condition that remains largely undiagnosed. We aimed to assess the level of awareness and knowledge of OSA among the general population.MethodsThe Singapore Health 2 was a population-based study that comprised interview and health screening components. Out of 2720 subjects who completed the interview component, 2080 subjects gave consent for further health surveys. We contacted these subjects and conducted a structured telephone interview.ResultsWe completed 1306 telephone interviews (response rate 62.8%). Two hundred and eighty-one (21.5%) respondents were aware of OSA, but only 170 (13.0%) respondents could define OSA correctly. A total of 77 (5.9%), 158 (12.1%), 150 (11.5%) and 110 (8.4%) respondents were able to correctly list at least one risk factor, symptom, health consequence and treatment options for OSA, respectively. The most common sources of information about OSA were traditional media such as newspapers (42.0%), internet (14.2%) or relatives and friends (14.6%). On multivariate analysis, respondents were more likely to define OSA correctly if they were older (≥61years), (odds ratio of 2.99, 95% Confidence Interval [CI]: 1.66–5.41), were Chinese as compared to Indians (odds ratio 2.63, 95% CI: 1.46–4.72), had higher levels of income (odds ratio 2.18, 95% CI 1.16–4.10) and post-secondary education (odds ratio 2.87, 95% CI: 1.28–6.45).ConclusionAwareness and knowledge of OSA among the general population is currently poor. The effectiveness of ongoing health education campaigns to increase awareness should be monitored by examining temporal trends in public knowledge of sleep apnea.     

Sleep duration on workdays or nonworkdays and cardiac–cerebral vascular diseases in Southern China

ObjectivesThis study aimed to assess the relationship between sleep duration on work or nonworkdays and myocardial infarction (MI) and stroke in Southern China.MethodsA cross-sectional survey was conducted among 15,364 participants of age ≥15 years in Southern China from November 2013 to August 2014. Data on self-reported duration of sleep on workdays or nonworkdays as well as history of MI and stroke were collected in the questionnaire. The subjects were examined for weight, height, waist circumference, and blood pressure. Multivariate logistic regression analyses were performed to evaluate the association of sleep duration with MI and stroke.ResultOverall, compared with a sleep duration of 6–8 h, individuals who slept <6 h on workdays and nonworkdays were associated with increased risk for MI (odds ratio [OR] = 3.17, 2.04). Furthermore, individuals who slept >8 h on workdays and nonworkdays were associated with an increased risk for stroke (OR = 1.86, 1.54). Although this association persisted in men and subjects aged <65 years, we also observed that long sleep duration on workdays was associated with MI, especially among women, and short sleep duration on nonworkdays was associated with stroke among those aged 65 years or older. Participants with abnormal sleep duration and hypertension had higher risk of MI and stroke. Sleep debt was independently associated with MI risk, but not stroke (OR = 1.40; 95% confidence interval [CI]: 1.06–1.86), specifically among men aged <65 years.ConclusionsCompared with a sleep duration of 6–8 h, both short and long sleep duration were associated with the prevalence of MI and stroke and these associations were more pronounced among hypertensive persons, and tended to vary by age and sex. Moreover, sleep debt was linked to greater MI risk among men aged <65 years. These findings suggest that we should develop a healthy biological clock.     

Developmental programing of thirst and sodium appetite

Thirst and sodium appetite are the sensations responsible for the motivated behaviors of water and salt intake, respectively, and both are essential responses for the maintenance of hydromineral homeostasis in animals. These sensations and their related behaviors develop very early in the postnatal period in animals. Many studies have demonstrated several pre- and postnatal stimuli that are responsible for the developmental programing of thirst and sodium appetite and, consequently, the pattern of water and salt intake in adulthood in need-free or need-induced conditions. The literature systematically reports the involvement of dietary changes, hydromineral and cardiovascular challenges, renin–angiotensin system and steroid hormone disturbances, and lifestyle in these developmental factors. Therefore, this review will address how pre- and postnatal challenges can program lifelong thirst and sodium appetite in animals and humans, as well as which neuroendocrine substrates are involved. In addition, the possible epigenetic molecular mechanisms responsible for the developmental programing of drinking behavior, the clinical implications of hydromineral disturbances during pre- and postnatal periods, and the developmental origins of adult hydromineral behavior will be discussed.     

Group cognitive behavioural treatment of youth anxiety in community based clinical practice: Clinical significance and benchmarking against efficacy

The efficacy of a group cognitive behavioural therapy (CBT) programme (Cool Kids) of youth anxiety has been demonstrated at university clinics in Australia and Denmark and similar CBT programmes have been found effective within community settings in other countries. However, most effectiveness studies of CBT for youth anxiety have either used a mixture of CBT guidelines, or translated protocols not previous tested in an efficacy trial. This study used a benchmarking strategy to compare outcomes from the same CBT programme used at a university research clinic (N = 87) and community centres (N = 82). There was a significant reduction on both clinical and self-report measures of youth anxiety over time with medium to large effect sizes within both samples. Treatment effects on self-report measures of youth anxiety were significantly larger within the university sample, while changes in clinical measures of youth anxiety were similar in the two samples. Overall these findings suggest that an efficacious CBT group treatment programme developed within research contexts is transportable to community centres. Despite being effective within the community, the results indicate that the treatment may lose some of its efficacy when disseminated to the community.     

The clinimetric properties of aerobic and anaerobic fitness measures in adults with cerebral palsy: A systematic review of the literature

ObjectiveTo analyze the clinimetric properties of maximal aerobic and anaerobic fitness measurement protocols in adults with cerebral palsy (CP).Data SourcesA systematic search through March 2015 of databases PubMed, Embase, SPORTDiscus and PsycINFO was performed with medical subject heading terms for ‘cerebral palsy’ combined with search terms adults or adolescents and multiple text words for fitness and exercise tests that yielded 864 articles.Study SelectionAbstracts were screened by two reviewers to identify use of maximal fitness measurements in adolescents (14–18 yrs) or adults (>18 yrs) with CP of all abilities. Ninety-four articles were reviewed. No studies of adolescent (14–18 yrs) qualified. Eight articles reported clinimetric properties for adults with CP who walk or propel a wheelchair independently. Five articles reported on aerobic capacity, one reported on anaerobic capacity and two reported on both.Data ExtractionMethodological quality of the studies was rated using portions of the COSMIN (COnsensus-based Standards for the selection of health status Measurement INstruments) checklist. Quality of the measurement protocols was evaluated based on statistical strength of the clinimetrics. Synthesis of the overall evidence was based on the Cochrane review group guidelines which combine methodological quality and statistical strength.Data SynthesisEight articles reported on 4 aerobic and 1 anaerobic protocols. Overall synthesis revealed that for ambulatory adults with CP there is (i) moderate evidence for good reliability and good construct validity of maximal aerobic and anaerobic cycle tests, (ii) moderate evidence for good criterion validity of sub-maximal aerobic cycle tests, and (iii) strong evidence for poor criterion validity of the six-minute walk test as a maximal aerobic test. And for adults who propel a wheelchair there is limited evidence of good reliability for maximal aerobic wheelchair ergometer tests.ConclusionsLimited quality research exists on the clinimetric properties of aerobic and anaerobic capacity measures for adults with CP who have independent mobility. Quality aerobic and anaerobic measures for adults with more severe mobility impairments are absent.     

Sleep and memory in mammals,birds and invertebrates

Sleep supports memory consolidation. Based on studies in mammals, sleep-dependent consolidation has been conceptualized as ‘active system consolidation’. During waking, information is encoded into an initial store (hippocampus). During subsequent sleep, some of the newly encoded memories are selected to be reactivated and redistributed toward networks serving as long-term store (e.g., neocortex), whereby memories become transformed into more general, schema-like representations. Here we asked whether sleep in non-mammalian species might play a comparable role for memory. The literature review revealed that sleep produces enhancing effects on memory in all non-mammalian species studied. Furthermore, across species some of the hallmarking features of active system consolidation were identified: Studies of filial imprinting in chicks suggest that a redistribution of imprinting memory toward long-term storage sites occurs during sleep; song learning in birds appears to be driven by reactivations of song representations during sleep; studies of bees demonstrated the selectivity of sleep-dependent consolidation, benefiting extinction but not original classical conditioning. Although overall fragmentary, first evidence in non-mammalian species suggests active system consolidation might be an evolutionary conserved function of sleep.     

Early life exposure to sevoflurane impairs adulthood spatial memory in the rat

Sevoflurane is a general anesthetic commonly used in the pediatric setting because it is sweet-smelling, nonflammable, fast acting and has a very short recovery time. Although recent clinical data suggest that early anesthesia exposure is associated with subsequent learning and memory problems, it is difficult to determine the exact scope of developmental neurotoxicity associated with exposure to specific anesthetics such as sevoflurane. This is largely due to inconsistencies in the literature. Thus, in the present studies we evaluated the effect of early life exposure to sevoflurane (1%, 2%, 3% or 4%) on adulthood memory impairment in Sprague-Dawley rats. Animals were exposed to different regimens of sevoflurane anesthesia on postnatal days (PNDs) 3, 7, or 14 or at 7 weeks (P7W) of age and spatial memory performance was assessed in adulthood using the Morris Water Maze (MWM). Rats exposed to sevoflurane exhibited significant memory impairment which was concentration and exposure duration dependent. Disruption of MWM performance was more severe in animals exposed on both PNDs 3 and 7 than in animals exposed on both PNDs 3 and 14. The younger the animal's age at the time of exposure, the more significant the effect on later MWM performance. Compared to the neonates, animals exposed at P7W were relatively insensitive to sevoflurane: memory was impaired in this group only after repeated exposures to low doses or single exposures to high doses. Early life exposure to sevoflurane can result in spatial memory impairments in adulthood and the shorter the interval between exposures, the greater the deficit.     

Association between severity of untreated sleep apnoea and postoperative complications following major cardiac surgery: a prospective observational cohort study

ObjectiveTo examine whether untreated sleep apnoea is associated with prolonged Intensive Care Unit (ICU) stay and increased frequency of postoperative ICU complications, in patients undergoing major cardiac surgery.Patients/methodsAdult patients, undergoing elective coronary artery bypass grafting with or without cardiac valve surgery, between March 2013 and July 2014, were considered. We excluded patients participating in other interventional studies, those who had a tracheostomy before surgery, required emergency surgery or were due to be admitted on the day of surgery. Patients underwent inpatient overnight oximetry on the night prior to their surgery to assess for the presence of sleep apnoea. Since oximetry alone cannot differentiate obstructive from central apnoea, the results are reported as sleep apnoea which was diagnosed in patients with an arterial oxygen desaturation index (ODI) ≥ 5/h.ResultsThe primary outcome measure was length of stay (LoS) in ICU in days. The secondary outcome was a composite measure of postoperative complications in ICU. Multivariate models were developed to assess associations between ODI and the primary and secondary outcome measures, adjusting for preselected predictor variables, relative to primary and secondary outcomes. There was no significant association between ODI and ICU LoS, HR 1.0, 95% CI 0.99–1.02; p = 0.12. However we did find a significant association between ODI and postoperative complications in the ICU, OR = 1.1; 95% CI 1.02–1.17; p = 0.014. The probability of developing complications rose with higher ODI, reflecting sleep apnoea severity.ConclusionsAcknowledging the limitations of this prospective study, untreated sleep apnoea did not predict an increased length of stay in ICU but we do report an association with postoperative complications in patients undergoing major cardiac surgery.     

Clinical correlates of graph theory findings in temporal lobe epilepsy

PurposeTemporal lobe epilepsy (TLE) is considered a brain network disorder, additionally representing the most common form of pharmaco-resistant epilepsy in adults. There is increasing evidence that seizures in TLE arise from abnormal epileptogenic networks, which extend beyond the clinico-radiologically determined epileptogenic zone and may contribute to the failure rate of 30–50% following epilepsy surgery. Graph theory allows for a network-based representation of TLE brain networks using several neuroimaging and electrophysiologic modalities, and has potential to provide clinicians with clinically useful biomarkers for diagnostic and prognostic purposes.MethodsWe performed a review of the current state of graph theory findings in TLE as they pertain to localization of the epileptogenic zone, prediction of pre- and post-surgical seizure frequency and cognitive performance, and monitoring cognitive decline in TLE.ResultsAlthough different neuroimaging and electrophysiologic modalities have yielded occasionally conflicting results, several potential biomarkers have been characterized for identifying the epileptogenic zone, pre-/post-surgical seizure prediction, and assessing cognitive performance. For localization, graph theory measures of centrality have shown the most potential, including betweenness centrality, outdegree, and graph index complexity, whereas for prediction of seizure frequency, measures of synchronizability have shown the most potential. The utility of clustering coefficient and characteristic path length for assessing cognitive performance in TLE is also discussed.ConclusionsFuture studies integrating data from multiple modalities and testing predictive models are needed to clarify findings and develop graph theory for its clinical utility.     

Catathrenia,a REM predominant disorder of arousal?

ObjectivesCatathrenia is an uncommon and poorly understood disorder, characterized by groaning during sleep occurring in tandem with prolonged expiration. Its classification, pathogenesis, and clinical relevance remain debated, substantially due to the limited number of cases reported to date. We report a series of consecutive cases of catathrenia, their clinical and polysomnographic characteristics, and their subsequent management.MethodsConsecutive patients with catathrenia who had undergone full polysomnography in our institution over a 5.5-year period were included. Catathrenia events (CEs) were examined in clusters, which formulated catathrenia periods (CPs). The relationships between CPs, sleep stage distribution, electroencephalogram (EEG) arousals, and other sleep parameters were assessed, along with the clinical presentation and management of catathrenic patients.ResultsA total of 427 CPs were identified in 38 patients, 81% arising from rapid eye movement (REM) sleep. EEG arousals preceded or coincided with the onset of 84% of CPs, which were of longer duration than those not associated with an arousal (57.3 ± 56.8 vs. 32.2 ± 29.4 s, p < 0.001). Each CE had a characteristic airflow signal, with inspiration preceding a protracted expiration and a brief more rapid exhalation, followed by deep inspiration. Although the majority of patients were referred on the basis of bed partner complaints, 44.7% complained of daytime sleepiness. Continuous positive airway pressure therapy and sleep-consolidating pharmacotherapy led to subjective improvement, but were limited by poor long-term adherence.ConclusionsIn the largest series of catathrenia patients reported to date, we found that this rare disorder is characterized by a distinct breathing pattern and arises predominantly from REM sleep, with arousals almost uniformly preceding or coinciding with the onset of CPs.     

Responses to voluntary hyperventilation in children with separation anxiety disorder: Implications for the link to panic disorder

BackgroundBiological theories on respiratory regulation have linked separation anxiety disorder (SAD) to panic disorder (PD). We tested if SAD children show similarly increased anxious and psychophysiological responding to voluntary hyperventilation and compromised recovery thereafter as has been observed in PD patients.MethodsParticipants were 49 children (5–14 years old) with SAD, 21 clinical controls with other anxiety disorders, and 39 healthy controls. We assessed cardiac sympathetic and parasympathetic, respiratory (including pCO₂), electrodermal, electromyographic, and self-report variables during baseline, paced hyperventilation, and recovery.ResultsSAD children did not react with increased anxiety or panic symptoms and did not show signs of slowed recovery. However, during hyperventilation they exhibited elevated reactivity in respiratory variability, heart rate, and musculus corrugator supercilii activity indicating difficulty with respiratory regulation.ConclusionsReactions to hyperventilation are much less pronounced in children with SAD than in PD patients. SAD children showed voluntary breathing regulation deficits.