Effects of manipulating body temperature on sleep in postmenopausal women

Study objectivesA decline in sleep quality, slow wave sleep (SWS) and slow wave activity (SWA) are common in older adults. Prior studies have shown that manipulating body temperature during sleep can increase SWS/SWA. The aim of this study was to determine the effects of manipulation of body temperatures during sleep, using a high heat capacity mattress, on SWS/SWA and heart rate in post-menopausal women.MethodsTwenty-four healthy postmenopausal women between 40 and 75 years of age (mean age 62.4 ± 8.2 years, mean BMI 25.4 ± 3.5 kg/m²) were randomized in a single-blind, counterbalanced, cross-over manner to sleep on either a high heat capacity mattress (HHCM) or a low heat capacity mattress (LHCM) a week apart. Sleep was recorded using polysomnography during an 8-h sleep opportunity. Core and peripheral temperature were recorded using an ingestible capsule and thermochron respectively.ResultsIn comparison to the LHCM, sleep on HHCM exhibited a selective increase in SWS (average increase in Stage N3 of 9.6 min (2.1%), p = 0.04) and in slow oscillatory (SO) activity (0.5–1 Hz) in the first NREM/REM cycle (p = 0.04). In addition, the HHCM induced a greater reduction in core body temperature (p = 0.002). The reduction in core body temperature (first 180 min after lights out) from LHCM to HHCM was associated (r = 0.5, p = 0.012) with the increase in SO activity (SO cycle 1 and 2/cycle 3 and 4). Average heart rate was 1.6 beats/minute lower across the night on the HHCM compared to the LHCM (p = 0.001).ConclusionsThe results of this study indicate that manipulation of body temperature during sleep may be a useful approach to enhance SWS sleep in postmenopausal women.     

Validation of semiautomatic scoring of REM sleep without atonia in patients with RBD

Objective/BackgroundTo evaluate REM sleep without atonia (RSWA) in REM sleep behavior disorder (RBD) several automatic algorithms have been developed. We aimed to validate our algorithm (Mayer et al., 2008) in order to assess the following: (1). capability of the algorithm to differentiate between RBD, night terror (NT), somnambulism (SW), Restless legs syndrome (RLS), and obstructive sleep apnea (OSA), (2). the cut-off values for short (SMI) and long muscle activity (LMI), (3). which muscles qualify best for differential diagnosis, and (4). the comparability of RSWA and registered movements between automatic and visual analysis of videometry.Patients/MethodsRSWA was automatically scored according to Mayer et al., 2008 in polysomnographies of 20 RBD, 10 SW/NT, 10 RLS and 10 OSA patients. Receiver operating characteristic (ROC) curves were used to determine the sensitivity and specificity of SMI and LMI. Independent samples were calculated with t-tests. Boxplots were used for group comparison. The comparison between motor events by manual scoring and automatic analysis were performed with “Visual Basic for Applications” (VBA) for every hundredth second.ResultsOur method discriminates RBD from SW/NT, OSA and RLS with a sensitivity of 72.5% and a specificity of 86.7%. Automatic scoring identifies more movements than visual video scoring. Mentalis muscle discriminates the sleep disorders best, followed by FDS, which was only recorded in SW/NT. Cut-off values for RSWA are comparable to those found by other groups.ConclusionThe semi-automatic RSWA scoring method is capable to confirm RBD and to discriminate it with moderate sensitivity from other sleep disorders.     

Selective slow-wave sleep suppression affects glucose tolerance and melatonin secretion. The role of sleep architecture

ObjectivesOur study aimed to assess the impact of one night of slow-wave sleep (SWS) suppression on glucose tolerance, and explore whether melatonin plays a role in glucose tolerance impairment after SWS suppression.MethodsIn sum, 20 volunteers participated in two experimental sessions: a session with SWS suppression during one night's sleep and a session with a regular night's sleep (control). Each session included collecting seven salivary samples. The following morning, an oral glucose tolerance test (OGTT) was performed.ResultsSWS suppression effects depended on the individual blood glucose response to the OGTT. During the control session, ‘responders’ (N = 11), already presented with low glucose tolerance, which further declined after SWS suppression. ‘Non-responders’ (N = 9) experienced high glucose tolerance in both conditions. Among the responders, SWS suppression led to an increase in melatonin at the moment of awakening, while in non-responders melatonin increased during the first half of the night. In both conditions, responders were characterized by a shorter total sleep time (TST) and less rapid eye movement (REM) sleep. During SWS suppression, they had more non-rapid eye movement (NREM) stage 1 and longer nocturnal wakefulness. Responders and non-responders showed a comparable amount of SWS.ConclusionsThis study highlights three key findings: first, SWS suppression leads to an increase in salivary melatonin; second, melatonin's effect on glucose tolerance depends on its secretion timing; and third, durations of REM sleep and nocturnal awakenings, appear to play an important role in melatonin secretion and glucose tolerance, indicating the potential clinical relevance of these findings for type 2 diabetes risk assessment.     

Motor dyscontrol in narcolepsy: rapid-eye-movement (REM) sleep without atonia and REM sleep behavior disorder.

Narcolepsy involves abnormalities of rapid-eye-movement (REM) sleep, including a short latency to the onset of REM sleep, hypnagogic hallucinations, and sleep paralysis. In addition, persistence of muscle tone by electromyographic criteria or excessive muscle twitching during REM sleep or both have been reported in treated and untreated narcoleptic patients. We report that another previously described abnormality of REM sleep, REM sleep behavior disorder, may also be a symptom of narcolepsy. This disorder was found in 10 narcoleptic patients during routine clinical evaluations involving polysomnography and multiple sleep latency tests. During REM sleep, 7 additional narcoleptic patients displayed persistent muscle tone and/or excessive twitching, which we believe to be subclinical components of REM sleep behavior disorder. These 17 patients, diagnosed by established criteria for narcolepsy and for REM sleep behavior disorder, ranged in age from 8 to 74 years. Seventy-one percent were male. Narcolepsy and REM sleep behavior disorder most commonly emerged in tandem. In 3 patients, treatment of narcolepsy-cataplexy with stimulants and tricyclics either induced or exacerbated REM sleep behavior disorder.     

Nocturnal sleep architecture in idiopathic hypersomnia: a systematic review and meta-analysis

BackgroundCurrent sleep medicine nosology places increased importance on nocturnal polysomnographic sleep recordings in the diagnosis of central nervous system disorders of hypersomnolence, particularly idiopathic hypersomnia (IH).ObjectiveDetermine what differences in sleep staging and architecture exist between IH and healthy controls using meta-analysis.MethodsSystematic review identified relevant studies that included nocturnal polysomnography data for IH and healthy control groups. Meta-analysis compared standardized mean differences (Hedge's g) for total sleep time (TST), sleep onset latency (SOL), sleep efficiency (SE), rapid eye movement (REM) sleep percentage, slow wave sleep (SWS) percentage, and REM latency (REML). Moderator analyses were also conducted for variables with significant heterogeneity among studies.ResultsThe meta-analysis included 10 studies. Relative to controls, IH demonstrated increased TST (pooled g = 0.92; 95% CI: 0.46 to 1.38, p < 0.0001) and REM percentage (pooled g = 0.36, 95% CI: 0.09 to 0.64, p = 0.01), decreased SOL (pooled g = −0.46; 95% CI: −0.81 to −0.12, p = 0.009) and SWS percentage (pooled g = −0.28, 95% CI: −0.50 to −0.07, p = 0.01), without significant differences in SE (pooled g = 0.03; 95% CI: −0.32 to 0.38, p = 0.86) or REML (pooled g = 0.14, 95% CI: −0.21 to 0.49, p = 0.42). Moderator analysis demonstrated a significant effect of sex on SE, with a higher proportion of women to men significantly predicting lower SE between in IH and controls (p < 0.0001).ConclusionsIH is associated with several changes in sleep staging and architecture relative to healthy persons, including alterations in REM and SWS not currently delineated in nosological constructs. Further research is indicated to clarify how these findings are related the pathophysiology of IH and related disorders.     

The effect of sildenafil on sleep respiratory parameters and heart rate variability in obstructive sleep apnea

ObjectiveTo evaluate the magnitude of effects of sildenafil on respiratory parameters and heart rate variability (HRV) in slow wave sleep (SWS) and REM sleep of patients with severe obstructive sleep apnea (OSA).MethodsThirteen male patients with untreated severe OSA (aged 43 ± 10 years, body mass index of 26.7 ± 1.9 kg/m²) were studied on two nights, one with sildenafil 50 mg and one with a placebo, in a double-blind, randomized fashion. All-night polysomnography and HRV were simultaneously recorded. Short-term HRV measures were performed in apnea-free intervals. Respiratory parameters were separately assessed in non-REM and REM sleep and compared to total sleep time (TST). Short-term HRV analysis was conducted in samples with regular respiration obtained in SWS and REM sleep.ResultsComparing to placebo, during sildenafil night there was an increase in apnea–hypopnea index (AHI) in TST and also in non-REM and REM sleep. Increase in central AHI occurred in non-REM sleep; increase in obstructive AHI and decrease in oxyhemoglobin saturation occurred in both non-REM and REM sleep. Additionally, an increase in arousal index and in low/high frequency component of HRV ratio (LF/HF) was significant only in REM sleep. Correlation between sleep architecture and respiratory parameters were more frequent in non-REM sleep for placebo and in REM sleep for sildenafil.ConclusionIn severe OSA, the use of sildenafil 50 mg at bedtime plays a detrimental role on respiratory parameters in both non-REM and REM sleep, fragmentation in REM sleep, and a prolonged increase in LH/HF component of HRV after resumption of ventilation.     

Intraindividual long-term stability of sleep electroencephalography in school-aged children

ObjectiveTo examine the long-term stability of sleep duration, sleep continuity, and sleep architecture assessed via unattended home sleep electroencephalography (EEG) during middle childhood.MethodsA total of 69 healthy children (18 girls and 51 boys) aged 8.2 years (standard deviation = 1.3 years) at T1 underwent unattended home sleep EEG on two nights separated by 18.5 months (standard deviation = 3.9 months). Of the children, 34 (49.3%) children were born prematurely (<32 gestational weeks; mean birth weight = 1367 g) and 35 (50.7%) children were born at term (mean birth weight = 3275 g).ResultsWe found moderate to substantial stability (all p <0.001) for total sleep time (TST; intraclass correlation coefficient [ICC] = 0.65), slow wave sleep (SWS; min, %: ICC = 0.49), and stage 2 sleep (min; ICC = 0.47), and found fair stability (all p <0.013) for sleep efficiency (ICC = 0.28), nocturnal awakenings (ICC = 0.33), stage 2 sleep (%; ICC = 0.32), and rapid eye movement (REM) sleep (min: ICC = 0.33; %: ICC = 0.27). Prematurity status was not associated with stability of sleep EEG indices over time.ConclusionsLong-term follow-up of one night of unattended home sleep EEG during middle childhood reveals that TST, stage 2 sleep, and SWS are relatively stable, trait-like characteristics. This applies less strongly for sleep efficiency, nocturnal awakenings, and REM sleep. Stage 1 sleep and REM latency showed no stability.     

Is obstructive sleep apnea a problem in Parkinson’s disease?

BackgroundParkinson’s disease (PD) is associated with sleep disorders and daytime sleepiness. Upper airway dysfunction in PD may promote obstructive sleep apnea. However, the frequency and clinical relevance of sleep-disordered breathing in PD remains unclear.MethodsSleep apnea symptoms, cardiovascular events and treatment were collected in 100 patients with PD (50 unselected, consecutive patients matched for age, sex and body mass index with 50 patients referred for sleepiness) and 50 in-hospital controls. The motor and cognitive status was evaluated in patients with PD. The 150 subjects underwent a video-polysomnography.ResultsSleep apnea (defined as an apnea–hypopnea index greater than 5) was less frequent in the PD group (27% patients, including 6% with mild, 11% with moderate and 10% with severe sleep apnea) than in the control group (40% in-hospital controls, p < 0.002). Sleep apnea was not associated with increased sleepiness, nocturia, depression, cognitive impairment and cardiovascular events in patients with PD. Sleep apnea was more frequent and severe in the most disabled patients. Patients with PD did not display sleep hypoventilation, stridor and abnormal central sleep apnea. In patients with REM sleep behavior disorders, snoring and obstructive sleep apnea occurred during REM sleep, although the chin muscle tone was maintained.ConclusionObstructive sleep apnea does not seem to be a clinically relevant issue in PD. Daytime sleepiness, nocturia and cognitive impairment are mostly caused by other, non-apneic mechanisms. The maintenance of chin muscle tone during REM sleep behavior disorder has no influence on the frequency of apneic events.     

Slow-wave sleep and androgens: selective slow-wave sleep suppression affects testosterone and 17α-hydroxyprogesterone secretion

ObjectivesLevels of steroid hormones such as androgens and cortisol exhibit circadian variation, and their fluctuations are related to the sleep-wake cycle. Currently, the functional role of different stages of sleep in steroid hormone secretion remains unclear. The present study aims to explore the effect of slow-wave sleep (SWS) suppression on morning levels of cortisol and androgens.MethodsTwelve healthy male volunteers participated in two experimental sessions: a session with selective SWS suppression during night sleep and a session with regular night sleep (control). SWS suppression was achieved by stimulation using an acoustic tone. Salivary samples were collected in the morning immediately after awakening and again 40 min later. The samples were analysed by liquid chromatography-tandem mass spectrometry for testosterone, androstenedione (Ad), dehydroepiandrosterone (DHEA), 17α-hydroxyprogesterone (17-OHP), and cortisol.ResultsSWS suppression reduced overall SWS duration by 54.2% without significant changes in total sleep time and sleep efficiency. In the session with selective SWS suppression, the average level of morning testosterone was lower than in the control session (p = 0.017). Likewise, 17-OHP was lower in the SWS suppression condition (p = 0.011) whereas the ratio of DHEA/Ad was higher (p = 0.025). There were no significant differences between sessions in cortisol, Ad, or DHEA concentrations.ConclusionsThe effect of selective SWS suppression on morning levels of testosterone and 17-OHP points to the importance of SWS for the synthesis and secretion of androgens. These results suggest that chronic sleep problems, which lead to reduced SWS, increase the risk for the development of androgen deficiency in the long term.     

Nighttime melatonin secretion and sleep architecture: different associations in perimenopausal and postmenopausal women

BackgroundSleep quality typically decreases after menopause, but the underlying mechanisms are poorly understood. Concentrations of melatonin are lower and its secretion profiles different before and after menopause. However, whether and how melatonin and sleep architecture are associated in women of different reproductive states have not been examined to date.MethodsOvernight serum melatonin samples were taken from 17 perimenopausal and 18 postmenopausal healthy women. Sleep quality was measured with all-night polysomnography recordings.ResultsMelatonin concentrations tended to be the lowest during NREM sleep, and were associated with higher odds of transitions from wake to NREM sleep. The curves of predicted overnight melatonin values from linear mixed models varied according to sleep phases (NREM, REM, Wake) in perimenopausal, but not in postmenopausal women. In perimenopause higher melatonin area under curve (AUC) correlated with higher slow-wave activity (p = 0.043), and higher minimum concentrations with shorter slow-wave sleep (SWS) latency (p = 0.029). In postmenopause higher mean and maximum melatonin concentrations and AUC correlated with lower SWS percentage (p = 0.044, p = 0.029, p = 0.032), and higher mean (p = 0.032), maximum (p = 0.032) and minimum (p = 0.037) concentrations with more awakenings from REM sleep. In the age- and BMI- adjusted regression models, the association between higher maximum (p = 0.046) melatonin concentration and lower SWS percentage remained.ConclusionsThe relationship between melatonin and sleep architecture differed in perimenopausal and postmenopausal women. After menopause, high melatonin concentrations were associated with worse sleep. Whether these different patterns are related to aging of the reproductive system, and to decrease in menopausal sleep quality, remains to be elucidated.     

Surface EMG activity during REM sleep in Parkinson's disease correlates with disease severity

ObjectivesOver 40% of individuals with Parkinson's disease (PD) have rapid eye movement sleep behavior disorder (RBD). This is associated with excessive sustained (tonic) or intermittent (phasic) muscle activity instead of the muscle atonia normally seen during REM sleep. We examined characteristics of manually-quantitated surface EMG activity in PD to ascertain whether the extent of muscle activity during REM sleep is associated with specific clinical features and measures of disease severity.MethodsIn a convenience sample of outpatients with idiopathic PD, REM sleep behavior disorder was diagnosed based on clinical history and polysomnogram, and severity was measured using the RBD sleep questionnaire. Surface EMG activity in the mentalis, extensor muscle group of the forearms, and anterior tibialis was manually quantitated. Percentage of REM time with excessive tonic or phasic muscle activity was calculated and compared across PD and RBD characteristics.ResultsAmong 65 patients, 31 had confirmed RBD. In univariate analyses, higher amounts of surface EMG activity were associated with longer PD disease duration (srho = 0.34; p = 0.006) and greater disease severity (p < 0.001). In a multivariate regression model, surface EMG activity was significantly associated with RBD severity (p < 0.001) after adjustment for age, PD disease duration, PD severity and co-morbid sleep abnormalities.ConclusionSurface EMG activity during REM sleep was associated with severity of both PD and RBD. This measure may be useful as a PD biomarker and, if confirmed, may aid in determining which PD patients warrant treatment for their dream enactment to reduce risk of injury.     

Auditory arousal responses and thresholds during REM and NREM sleep of sleepwalkers and controls

BackgroundIt has been suggested that sleepwalkers are more difficult to awaken from sleep than are controls. However, no quantified comparisons have been made between these two populations. The main goal of this study was to assess arousal responsiveness via the presentation of auditory stimuli (AS) in sleepwalkers and controls during normal sleep and recovery sleep following sleep deprivation.MethodsTen adult sleepwalkers and 10 age-matched control subjects were investigated. After a screening night, participants were presented with AS during slow-wave sleep (SWS), REM, and stage 2 sleep either during normal sleep or daytime recovery sleep following 25 h of sleep deprivation. The AS conditions were then reversed one week later.ResultsWhen compared to controls sleepwalkers necessitated a significantly higher mean AS intensity (in dB) to induce awakenings and arousal responses during REM sleep whereas the two groups’ mean values did not differ significantly during SWS and stage 2 sleep. Moreover, when compared to controls sleepwalkers had a significantly lower mean percentage of AS that induced arousal responses during REM sleep while the opposite pattern of results was found during SWS.ConclusionsThe data indicate that sleepwalkers have a higher auditory awakening threshold than controls, but only for REM sleep. These findings may reflect a compensatory mechanism of the homeostatic process underlying sleep regulation during sleepwalkers’ REM sleep in reaction to their difficulties maintaining consolidated periods of NREM sleep.     

A comparative study of methods for automatic detection of rapid eye movement abnormal muscular activity in narcolepsy

ObjectiveTo evaluate rapid eye movement (REM) muscular activity in narcolepsy by applying five algorithms to electromyogram (EMG) recordings, and to investigate its value for narcolepsy diagnosis.Patients/methodsA modified version of phasic EMG metric (mPEM), muscle activity index (MAI), REM atonia index (RAI), supra-threshold REM EMG activity metric (STREAM), and Frandsen method (FR) were calculated from polysomnography recordings of 20 healthy controls, 18 clinic controls (subjects suspected with narcolepsy but finally diagnosed without any sleep abnormality), 16 narcolepsy type one without REM sleep behavior disorder (RBD), nine narcolepsy type one with RBD, and 18 narcolepsy type two. Diagnostic value of metrics in differentiating between groups was quantified by area under the receiver operating characteristic curve (AUC). Correlations among the metrics and cerebrospinal fluid hypocretin-1 (CSF-hcrt-1) values were calculated using linear models.ResultsAll metrics excluding STREAM found significantly higher muscular activity in narcolepsy one cases versus controls (p < 0.05). Moreover, RAI showed high sensitivity in the detection of RBD. The mPEM achieved the highest AUC in differentiating healthy controls from narcoleptic subjects. The RAI best differentiated between narcolepsy 1 and 2. Lower CSF-hcrt-1 values correlated with high muscular activity quantified by mPEM, sMAI, lMAI, PEM and FR (p < 0.05).ConclusionsThis automatic analysis showed higher number of muscle activations in narcolepsy 1 compared to controls. This finding might play a supportive role in diagnosing narcolepsy and in discriminating narcolepsy subtypes. Moreover, the negative correlation between CSF-hcrt-1 level and REM muscular activity supported a role for hypocretin in the control of motor tone during REM sleep.     

Heart rate variability and cordance in rapid eye movement sleep as biomarkers of depression and treatment response

ObjectivesThe relevance of rapid eye movement (REM) sleep in affective disorders originates from its well-known abnormalities in depressed patients, who display disinhibition of REM sleep reflected by increased frequency of rapid eye movements (REM density). In this study we examined whether heart rate variability (HRV) and prefrontal theta cordance, both derived from REM sleep, could represent biomarkers of antidepressant treatment response.MethodsIn an open-label, case-control design, thirty-three in-patients (21 females) with a depressive episode were treated with various antidepressants for four weeks. Response to treatment was defined as a ≥50% reduction of HAM-D score at the end of the fourth week. Sleep EEG was recorded after the first and the fourth week of medication. HRV was derived from 3-min artifact-free electrocardiogram segments during REM sleep. Cordance was computed for prefrontal EEG channels in the theta frequency band during tonic REM sleep.ResultsHRV during REM sleep was decreased in depressed patients at week four as compared to controls (high effect size; Cohen's d > 1), and showed a negative correlation with REM density in both, healthy subjects and patients at week four. Further, the fourteen responders had significantly higher prefrontal theta cordance as compared to the nineteen non-responders after the first week of antidepressant medication; in contrast, HRV at week one did not discriminate between responders and non-responders.ConclusionsOur data suggest that HRV in REM sleep categorizes healthy subjects and depressed patients, whereas REM sleep-derived prefrontal cordance may predict the response to antidepressant treatment in depressed patients.     

Sleep onset and first cycle of sleep in human subjects: change with time of day.

The first cycle of sleep was studied in different situations: normal night sleep, naps, diurnal sleep after night shifts (3 x 8 shift workers). Results show two types of first cycle: some started with SWS (normal cycles), others with REM (sleep onset REM periods: SOREMPs). (1) Normal cycles: the length of SWS in the first cycle was positively correlated with prior wakefulness; conversely, the latency of SWS decreased as prior wakefulness increased; the decrease was due to the decrease in the length of the previous stage II or of the sleep onset latency (SOL). Length of sleep onset (SO) showed only few variations. The structure of the first cycle of shift workers' sleep probably reflects an important sleep loss. (2) SOREMPs occcurred during diurnal sleep. Some hypotheses about these cycles are discussed including REM 'pressures' (circadian, sleep loss) and inter-individual variations.     

Polysomnographic and symptomatological analyses of major depressive disorder patients treated with mirtazapine.

OBJECTIVE: This study aimed to characterize the effects of mirtazapine on polysomnographic sleep, especially slow wave sleep (SWS) and rapid eye movement (REM) sleep, as well as its effects on clinical symptoms in patients with major depressive disorder (MDD). METHOD: Sixteen MDD patients were treated with mirtazapine 30 mg taken 30 minutes before bedtime. Polysomnographic and subjective sleep, as well as other clinical data, were collected at baseline and on Days or Nights 2, 9, 16, 30, and 58 during treatment. We used repeated measures analysis of variance, including pairwise comparison, to analyze data statistically. RESULTS: Mirtazapine administration increased total SWS and the SWS in the first sleep cycle, but not SWS in the second sleep cycle. The medication increased REM latency and the duration of the first REM episode; it also decreased the number of REM episodes. Simultaneously, mirtazapine significantly reduced wake-after-sleep onset and scores on the Athens Insomnia Scale. After patients took the medication, scores on the Hamilton Depression Rating Scale-17 (HDRS-17) decreased rapidly and continuously. The changes on the Beck Depression Inventory-II were consistent with those on the HDRS-17. The medication has a tendency to increase weight. CONCLUSIONS: Mirtazapine significantly improved sleep quality, reversed sleep markers of depression, and reduced depressive symptoms in this group of MDD patients.     

Few changes observed in polysomnographic-assessed sleep before and after completion of chemotherapy

ObjectiveSleep disturbance is prevalent among patients undergoing chemotherapy and is strongly associated with cancer-related fatigue (CRF). However, little objective evidence has been gathered on the patterns of sleep before and following chemotherapy.MethodsTwenty-six patients scheduled to receive chemotherapy were recruited. Sleep parameters were assessed by in-lab polysomnography (PSG) for two consecutive nights prior to first chemotherapy, approximately 3 weeks following the patients' last chemotherapy, and 3 months following the last treatment. Fatigue was measured on the first night of each of the two-night PSG assessments. We focus on Slow-Wave Sleep (SWS) as we hypothesized that a decrease of this restorative phase of sleep might be implicated in CRF.ResultsRepeated-measures analyses examining changes from baseline to the later time points in the proportion of time asleep spent in each of the four sleep architecture stages (Stage 1, Stage 2, SWS, and REM sleep) were non-significant, all Ps > 0.41. Canonical correlation analysis showed that the proportion of time spent in SWS was not significantly correlated with any of the three CRF measures at any of the three assessment points, P = 0.28.ConclusionsSleep architecture is not affected by cancer treatment. No evidence of an association between CRF and SWS, or alterations in SWS, was found.     

Let there be no light: the effect of bedside light on sleep quality and background electroencephalographic rhythms

ObjectivesArtificial lighting has been beneficial to society, but unnecessary light exposure at night may cause various health problems. We aimed to investigate how whole-night bedside light can affect sleep quality and brain activity.Patients and methodsTen healthy sleepers underwent two polysomnography (PSG) sessions, one with the lights off and one with the lights on. PSG variables related to sleep quality were extracted and compared between lights-off and lights-on sleep. Spectral analysis was performed to rapid eye movement (REM) sleep and non-REM (NREM) sleep epochs to reveal any light-induced differences in background brain rhythms.ResultsLights-on sleep was associated with increased stage 1 sleep (N1), decreased slow-wave sleep (SWS), and increased arousal index. Spectral analysis revealed that theta power (4–8 Hz) during REM sleep and slow oscillation (0.5–1 Hz), delta (1–4 Hz), and spindle (10–16 Hz) power during NREM sleep were decreased in lights-on sleep conditions.ConclusionsSleeping with the light on not only causes shallow sleep and frequent arousals but also has a persistent effect on brain oscillations, especially those implicated in sleep depth and stability. Our study demonstrates additional hazardous effect of light pollution on health.     

REM sleep without atonia is associated with increased rigidity in patients with mild to moderate Parkinson’s disease

ObjectiveIncreased muscle activity during rapid eye movement (REM) sleep (i.e. REM sleep without atonia) is common in people with Parkinson’s disease (PD). This study tested the hypotheses that people with PD and REM sleep without atonia (RSWA) would present with more severe and symmetric rigidity compared to individuals with PD without RSWA and age-matched controls.MethodsSixty-one individuals participated in this study (41 PD, 20 controls). An overnight sleep study was used to classify participants with PD as having either elevated (PD-RSWA+) or normal muscle activity (PD-RSWA−) during REM sleep. Quantitative measures of rigidity were obtained using a robotic manipulandum that passively pronated and supinated the forearm.ResultsQuantitative measures of forearm rigidity were significantly higher in the PD-RSWA+ group compared to the control group. Rigidity was significantly more asymmetric between limbs in the PD-RSWA− group compared with controls, while there was no significant difference in symmetry between the control and PD-RSWA+ groups.ConclusionIn people with mild to moderate PD, RSWA is associated with an increased and more symmetric presentation of upper limb rigidity.SignificanceDysfunction of brainstem systems that control muscle tone during REM sleep may contribute to increased rigidity during wakefulness in people with PD.     

The impact of antiseizure medications on polysomnographic parameters: a systematic review and meta-analysis

BackgroundOral antiseizure medications (ASMs) are first-line treatments for patients with epilepsy. However, ASMs may alter sleep architecture, adversely affecting patient outcomes. The meta-analysis aimed to elucidate the effect of ASMs on sleep architecture.MethodsPubMed, Embase, and Cochrane Central database (up to Febrary 2021) were searched for randomized control trials (RCT) with effects of ASMs on polysomnography parameters. A meta-analysis using a random-effects model was performed. We did not set limitation to the participants with underlying diagnosis of epilepsy.ResultsEighteen randomized-controlled trials fulfilled the eligibility criteria. The effects of five main groups of ASMs (sodium channel blockers, calcium channel blockers, GABA enhancers, synaptic vesicle glycoprotein 2A [SV2A] ligand, and broad-spetrum ASMs) on slow-wave sleep (SWS), rapid eye movement (REM) sleep, and sleep efficiency (SE) were analyzed. Compared with placebo, calcium channel blockers and GABA enhancers significantly increased SWS. GABA enhancers also decreased REM sleep percentage, whereas calcium channel blockers significantly increased SE. Sodium channel blockers, SV2A ligand and broad-spectrum ASMs did not affect SWS, REM sleep, or SE. The subgroup analysis revealed that gabapentin, pregabalin, and tiagabine increased the percentage of SWS. Tiagabine also decreased REM sleep, whereas pregabalin increased SE. Finally, levetiracetam did not affect SWS, REM sleep, and SE.ConclusionsThis meta-analysis indicated that ASMs can have a statistically significant effect on sleep parameters; the effect differs between ASMs.