Efficacy and safety of chloral hydrate in auditory brainstem response test: A systematic review and single-arm meta-analysis.

OBJECTIVES: To evaluate the safety and efficacy of chloral hydrate in auditory brainstem response (ABR) tests. SETTING AND DESIGN: In this study, the authors systematically searched both English (Embase, PubMed, and Web of Science) and Chinese (Chinese National Knowledge Infrastructure, Wanfang Data, and VIP Chinese Science) databases. Two authors independently performed data extraction and quality assessment. The pooled sedation failure rate and the pooled incidence of adverse events were calculated via a random-effects model. Sensitivity and subgroup analyses were performed to explore the sources of heterogeneity, and the PRISMA guideline was followed. PARTICIPANTS: Patients with ABR tests receiving chloral hydrate sedation. MAIN OUTCOME MEASURES: The pooled sedation failure rate and the pooled incidence of adverse events. RESULTS: A total of 23 clinical studies were included in the final analysis. The pooled sedation failure rate of patients who received chloral hydrate sedation before ABR examination was 10.0% [95% confidence interval (CI) (6.7%, 15.0%), I2 = 95%, p < .01]. There were significant differences in the prevalence of sedation failure between sample sizes greater than 200 and those less than or equal to 200 (5.6% vs. 19.6%, p < .01) and between the studies that reported sleep deprivation and those that did not report sleep deprivation (7.1% vs. 18.9%, p < .01). The pooled incidence of adverse events was 10.32% [95% CI (5.83%, 14.82%), I2 = 98.1%, p < .01]. CONCLUSIONS: Chloral hydrate has a high rate of sedation failure, adverse events, and potential carcinogenicity. Therefore, replacing its use in ABR tests with safer and more effective sedatives is warranted.

Sleep Patterns and Risk of Prostate Cancer: A Population-Based Case Control Study in France (EPICAP).

BACKGROUND: Sleep disturbances have been singled out for their implication in the risk of several cancer sites. However, results for prostate cancer are still inconsistent. METHODS: We used data from the EPICAP study, a French population-based case-control study including 819 incident prostate cancer cases and 879 controls frequency matched by age. Detailed information on sleep duration on work/free days, and sleep medication over lifetime was collected. RESULTS: Sleep duration and sleep deprivation were not associated with prostate cancer, whatever the aggressiveness of prostate cancer. However, sleep deprivation was associated with an increased prostate cancer risk among men with an evening chronotype [OR, 1.96; 95% confidence interval (CI), 1.04-3.70]. We also observed an increased risk of prostate cancer with higher duration of sleep medication use (Ptrend = 0.008). This association with long duration of sleep medication use (≥10 years) was more pronounced among men who worked at night 15 years or more (OR, 3.84; 95% CI, 1.30-11.4) and among nonusers of NSAID (OR, 2.08; 95% CI, 1.15-3.75). CONCLUSIONS: Our results suggested that chronotype, night work, or NSAID use could modify the association between sleep disorders and prostate cancer occurrence needing further investigations to go further. IMPACT: EPICAP is the first study, which investigates several sleep indicators taking into account potential effect modifiers. If our findings were confirmed, we could identify subgroups of men at higher risk of prostate cancer that may be accessible to preventive measures.

High cortical delta power correlates with aggravated allodynia by activating anterior cingulate cortex GABAergic neurons in neuropathic pain mice.

Patients with chronic pain often report being sensitive to pain at night before falling asleep, a time when the synchronization of cortical activity is initiated. However, how cortical activity relates to pain sensitivity is still unclear. Because sleep is characterized by enhanced cortical delta power, we hypothesized that enhanced cortical delta power may be an indicator of intensified pain. To test this hypothesis, we used pain thresholds tests, EEG/electromyogram recordings, c-Fos staining, and chemogenetic and pharmacological techniques in mice. We found that sleep deprivation or pharmacologic enhancement of EEG delta power by reserpine and scopolamine dramatically decreased mechanical pain thresholds, but not thermal withdrawal latency, in a partial sciatic nerve ligation model of neuropathic pain mice. On the contrary, suppression of EEG delta power using a wake-promoting agent modafinil significantly attenuated mechanical allodynia. Moreover, when EEG delta power was enhanced, c-Fos expression decreased in most regions of the cortex, except the anterior cingulate cortex (ACC), where c-Fos was increased in the somatostatin- and parvalbumin-positive GABAergic neurons. Chemogenetic activation of GABAergic neurons in ACC enhanced EEG delta power and lowered mechanical pain thresholds simultaneously in naive mice. However, chemogenetic inhibition of ACC GABAergic neurons could not block mechanical allodynia. These results provided compelling evidence that elevated EEG delta power is accompanied with aggravated neuropathic pain, whereas decreased delta power attenuated it, suggesting that enhanced delta power can be a specific marker of rising chronic neuropathic pain and that wake-promoting compounds could be used as analgesics in the clinic.

Dreamless: the silent epidemic of REM sleep loss.

We are at least as dream deprived as we are sleep deprived. Many of the health concerns attributed to sleep loss result from a silent epidemic of REM sleep deprivation. REM/dream loss is an unrecognized public health hazard that silently wreaks havoc with our lives, contributing to illness, depression, and an erosion of consciousness. This paper compiles data about the causes and extent of REM/dream loss associated with commonly used medications, endemic substance use disorders, rampant sleep disorders, and behavioral and lifestyle factors. It examines the consequences of REM/dream loss and concludes with recommendations for restoring healthy REM/dreaming.

Cancer-related insomnia.

Insomnia increases cancer symptom burden and impairs quality of life. The lack of standard definitions and treatment guidelines makes management difficult. Insomnia is common in most cancers but appears particularly so in lung, breast, and head and neck tumors. Older women seem most susceptible. Insomnia not only affects patients with cancer but also caregivers and families. Systematic screening is important. Few validated assessment scales are available. Nonpharmacologic therapies like cognitive behavioral therapy may help. New nonbenzodiazepine hypnotics may have some therapeutic advantages over older agents. Management of associated or contributory symptoms like fatigue, pain, and hot flashes with appropriate symptom-specific agents is important. Successful management may have a significant positive impact on global quality of life.

Reduced sleep and low adenosinergic sensitivity in cacna1a R192Q mutant mice.

STUDY OBJECTIVES: Adenosine modulates sleep via A(1) and A(2A) receptors. As the A(1) receptor influences Ca(V)2.1 channel functioning via G-protein inhibition, there is a possible role of the Ca(V)2.1 channel in sleep regulation. To this end we investigated transgenic Cacna1a R192Q mutant mice that express mutant Ca(V)2.1 channels that are less susceptible to inhibition by G-proteins. We hypothesized that Cacna1a R192Q mice could show reduced susceptibility to adenosine, which may result in a sleep phenotype characterized by decreased sleep. DESIGN: R192Q mutant and littermate wild-type mice were subjected to a 6-h sleep deprivation, treatment with caffeine (a non-specific adenosine receptor antagonist which induces waking), or cyclopentyladenosine (CPA, an A(1) receptor specific agonist which induces sleep). MEASUREMENTS AND RESULTS: Under baseline conditions, Cacna1a R192Q mice showed more waking with longer waking episodes in the dark period and less non-rapid eye movement (NREM) sleep, but equal amounts of REM sleep compared to wild-type. After treatment with caffeine R192Q mice initiated sleep 30 min earlier than wild-type, whereas after CPA treatment, R192Q mice woke up 260 min earlier than wild-type. Both results indicate that Cacna1a R192Q mice are less susceptible to adenosinergic input, which may explain the larger amount of waking under undisturbed baseline conditions. CONCLUSION: We here show that adenosinergic sleep induction, and responses to caffeine and CPA, are modified in the R192Q mutant in a manner consistent with decreased susceptibility to inhibition by adenosine. The data suggest that the A(1) receptor modulates sleep via the Ca(V)2.1 channel.

Longitudinal prospective assessment of sleep quality: before, during, and after adjuvant chemotherapy for breast cancer.

PURPOSE: Cross-sectional data suggest that many individuals with breast cancer experience significant sleep disturbance across the continuum of care. Understanding the longitudinal trajectory of sleep disturbance may help identify factors associated with its onset, severity, or influence on health-related quality of life (HRQL). Study objectives were to observe sleep quality in breast cancer patients prior to, during, and after completion of adjuvant chemotherapy, evaluate its relationship with HRQL and explore correlates over time. METHODS: Participants were administered patient-reported outcome measures including the Pittsburgh Sleep Quality Index (PSQI) and the Functional Assessment of Cancer Therapy--General (FACT-G), which assesses HRQL. Data were collected prospectively 3-14 days prior to beginning chemotherapy, cycle 4 day 1 of chemotherapy, and 6 months following initiation of chemotherapy. RESULTS: Participants (n = 80) were primarily women (97.5 %) with stage II (69.0 %) breast cancer. Total FACT-G scores were negatively correlated with global PSQI scores at each time point (rho = -0.46, -0.41, -0.45; all p < 0.001). Poor sleep quality (PSQI ≥ 5) was prevalent at all time points (48.5-65.8 %); however, there were no significant changes within participants over time. Correlates with sleep quality varied across time points. Participants with poor sleep quality reported worse overall HRQL, fatigue, depression, and vasomotor/endocrine symptoms. CONCLUSIONS: These findings suggest that early identification of sleep disturbance and ongoing assessment and treatment of contributing factors over the course of care may minimize symptom burden associated with chemotherapy and prevent chronic insomnia in survivorship.

Participation of the cholinergic system in the ethanol-induced suppression of paradoxical sleep in rats

Sleep disturbance is among the many consequences of ethanol abuse in both humans and rodents. Ethanol consumption can reduce REM or paradoxical sleep (PS) in humans and rats, respectively. The first aim of this study was to develop an animal model of ethanol-induced PS suppression. This model administered intragastrically (by gavage) to male Wistar rats (3 months old, 200-250 g) 0.5 to 3.5 g/kg ethanol. The 3.5 g/kg dose of ethanol suppressed the PS stage compared with the vehicle group (distilled water) during the first 2-h interval (0-2 h; 1.3 vs 10.2; P < 0.001). The second aim of this study was to investigate the mechanisms by which ethanol suppresses PS. We examined the effects of cholinergic drug pretreatment. The cholinergic system was chosen because of the involvement of cholinergic neurotransmitters in regulating the sleep-wake cycle. A second set of animals was pretreated with 2.5, 5.0, and 10 mg/kg pilocarpine (cholinergic agonist) or atropine (cholinergic antagonist). These drugs were administered 1 h prior to ethanol (3.5 g/kg) or vehicle. Treatment with atropine prior to vehicle or ethanol produced a statistically significant decrease in PS, whereas pilocarpine had no effect on minutes of PS. Although the mechanism by which ethanol induces PS suppression is not fully understood, these data suggest that the cholinergic system is not the only system involved in this interaction.

Sleep fragmentation and evidence for sleep debt in alcohol-exposed infants.

BACKGROUND: Infants exposed prenatally to alcohol are at increased risk for poor neurodevelopmental outcome including Sudden Infant Death Syndrome. AIM: To examine the relationship between prenatal alcohol exposure, sleep, arousal and sleep-related spontaneous motor movements in early infancy. STUDY DESIGN: Low-income women (N=13) were interviewed regarding pre- and pregnancy rates of alcohol, cigarette smoking and other substance use in the perinatal period. Infants were examined in a laboratory nap study using EEG, videography and actigraphy at 6-8 weeks of age. Estimates of maternal pre- and pregnancy alcohol use were used to divide infants into high vs. low maternal alcohol use groups. SUBJECTS: Mother-infant dyads recruited from a family practice clinic. OUTCOME MEASURES: Sleep-related spontaneous movements, behavioral state, and maternal assessments of infant alertness and irritability. RESULTS: Pre-pregnancy rates of alcohol consumption including binge drinking correlated with maternal report of poor infant alertness, and increased irritability. High maternal exposure groups showed increased sleep fragmentation, e.g., frequency and duration of wakefulness following sleep onset and decreased active sleep. Bout analysis of the temporal structure of sleep-related spontaneous movements showed significantly reduced bout duration associated with high maternal alcohol use. CONCLUSION: These results present evidence that prenatal alcohol exposure disrupts postnatal sleep organization and suppresses spontaneous movements during sleep, and increased sleep fragmentation promotes sleep deprivation. Results are consistent with the SIDS model of chronic sleep debt and suggest that attenuated sleep-related movements should be examined as an important modulator of cardiorespiratory functions during sleep in high-risk groups.

Staying awake puts pressure on brain arousal systems.

Many brain centers are involved in keeping us awake. One example is the recently discovered hypocretin system located in the posterior hypothalamus. In this issue of the JCI, Rao et al. show that, in mice, synapses targeting hypocretin neurons become stronger when wakefulness is prolonged beyond its physiological duration (see the related article beginning on page 4022). This increase in synaptic strength may be one of the mechanisms that help us to stay awake when we are sleep deprived, but it may also represent one of the signals telling the brain that it is time to sleep.

Prolonged wakefulness induces experience-dependent synaptic plasticity in mouse hypocretin/orexin neurons.

Sleep is a natural process that preserves energy, facilitates development, and restores the nervous system in higher animals. Sleep loss resulting from physiological and pathological conditions exerts tremendous pressure on neuronal circuitry responsible for sleep-wake regulation. It is not yet clear how acute and chronic sleep loss modify neuronal activities and lead to adaptive changes in animals. Here, we show that acute and chronic prolonged wakefulness in mice induced by modafinil treatment produced long-term potentiation (LTP) of glutamatergic synapses on hypocretin/orexin neurons in the lateral hypothalamus, a well-established arousal/wake-promoting center. A similar potentiation of synaptic strength at glutamatergic synapses on hypocretin/orexin neurons was also seen when mice were sleep deprived for 4 hours by gentle handling. Blockade of dopamine D1 receptors attenuated prolonged wakefulness and synaptic plasticity in these neurons, suggesting that modafinil functions through activation of the dopamine system. Also, activation of the cAMP pathway was not able to further induce LTP at glutamatergic synapses in brain slices from mice treated with modafinil. These results indicate that synaptic plasticity due to prolonged wakefulness occurs in circuits responsible for arousal and may contribute to changes in the brain and body of animals experiencing sleep loss.

A1 receptor and adenosinergic homeostatic regulation of sleep-wakefulness: effects of antisense to the A1 receptor in the cholinergic basal forebrain.

We hypothesized that adenosine, acting via the A1 receptor, is a key factor in the homeostatic control of sleep. The increase in extracellular levels of adenosine during prolonged wakefulness is thought to facilitate the transition to sleep by reducing the discharge activity of wakefulness-promoting neurons in the basal forebrain. Adenosine A1 receptor control of the homeostatic regulation of sleep was tested by microdialysis perfusion of antisense oligonucleotides against the mRNA of the A1 receptor in the magnocellular cholinergic region of the basal forebrain of freely behaving rats. After microdialysis perfusion of A1 receptor antisense in the basal forebrain, spontaneous levels of sleep-wakefulness showed a significant reduction in non-rapid eye movement (REM) sleep with an increase in wakefulness. After 6 hr of sleep deprivation, the antisense-treated animals spent a significantly reduced amount of time in non-REM sleep, with postdeprivation recovery sleep hours 2-5 showing a reduction of approximately 50-60%. There was an even greater postdeprivation reduction in delta power (60-75%) and a concomitant increase in wakefulness. All behavioral state changes returned to control (baseline) values after the cessation of antisense administration. Control experiments with microdialysis perfusion of nonsense (randomized antisense) oligonucleotides and with artificial CSF showed no effect during postdeprivation recovery sleep or spontaneously occurring behavioral states. Antisense to the A1 receptor suppressed A1 receptor immunoreactivity but did not show any neurotoxicity as visualized by Fluoro-Jade staining. These data support our hypothesis that adenosine, acting via the A1 receptor, in the basal forebrain is a key component in the homeostatic regulation of sleep.