Phenotypes for general behavior, activity, and body temperature in 3q29 deletion model mice.

Whole genome analysis has identified rare copy number variations (CNV) that are strongly involved in the pathogenesis of psychiatric disorders, and 3q29 deletion has been found to have the largest effect size. The 3q29 deletion mice model (3q29-del mice) has been established as a good pathological model for schizophrenia based on phenotypic analysis; however, circadian rhythm and sleep, which are also closely related to neuropsychiatric disorders, have not been investigated. In this study, our aims were to reevaluate the pathogenesis of 3q29-del by recreating model mice and analyzing their behavior and to identify novel new insights into the temporal activity and temperature fluctuations of the mouse model using a recently developed small implantable accelerometer chip, Nano-tag. We generated 3q29-del mice using genome editing technology and reevaluated common behavioral phenotypes. We next implanted Nano-tag in the abdominal cavity of mice for continuous measurements of long-time activity and body temperature. Our model mice exhibited weight loss similar to that of other mice reported previously. A general behavioral battery test in the model mice revealed phenotypes similar to those observed in mouse models of schizophrenia, including increased rearing frequency. Intraperitoneal implantation of Nano-tag, a miniature acceleration sensor, resulted in hypersensitive and rapid increases in the activity and body temperature of 3q29-del mice upon switching to lights-off condition. Similar to the 3q29-del mice reported previously, these mice are a promising model animals for schizophrenia. Successive quantitative analysis may provide results that could help in treating sleep disorders closely associated with neuropsychiatric disorders.

Assessing the Real-World, Long-Term Impact of Lemborexant on Sleep Quality in a Home-Based Clinical Study.

Purpose: Both subjective and objective evaluations are essential for the treatment of insomnia. Lemborexant has been shown to be effective in the long-term based solely on a subjective basis, and no long-term objective measures have been evaluated under natural sleep conditions. Small, lightweight sleep electroencephalogram (EEG) monitor was used, instead of polysomnography, to objectively evaluate sleep at home 4 and 12 weeks after lemborexant treatment. Patients and Methods: Adults and elderly subjects with insomnia disorder, per the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, were enrolled in this open-label, single-arm, single-center trial. Objective and subjective measures of sleep were prospectively assessed. Sleep disturbance, excessive sleepiness, and depressive symptoms were assessed using questionnaires. Results: A total of 45 subjects were screened, of which 33 were enrolled. Paired t-tests were conducted to evaluate changes in sleep variables and compared with the baseline; subjects showed significant improvements in objective sleep efficiency (SE) and subjective sleep parameters at weeks 4 and 12 following treatment with lemborexant. When baseline values were taken into account, a repeated-multivariate analysis of variance (MANOVA) revealed statistically significant changes in the objective measures. Sleep disturbance, excessive sleepiness, and depressive symptoms improved after three months of lemborexant treatment. Conclusion: Furthermore, lemborexant therapy improved nocturnal sleep, when measured objectively using sleep EEG monitoring at home, and improved daytime sleepiness and depressive symptoms in older adults with insomnia disorder.

Assessment of cognitive function and sleep-wake rhythms in community-dwelling older adults.

Disruption of the circadian rhythm and sleep-wake cycles is a consequence of aging and is associated with the cognitive decline and many neurodegenerative conditions. We investigated the bedtime, wake-up time, sleep timing (midpoint between bedtime and wake-up time), and sleep timing standard deviation (SD) using the actigraphy among 80 consecutive volunteers aged ≥ 60 years. Global cognitive function and executive function of detailed cognitive domains were evaluated using the mini-mental state examination (MMSE) and Wisconsin card sorting test (WCST) and subjective daytime sleepiness was assessed using the Epworth Sleepiness Scale (ESS). The category achievement (CA), total errors (TE), perseverative errors of Nelson (PEN), non-perseverative errors (NPE), and difficulties in maintaining set (DMS) on the WCST were significantly correlated with sleep timing SD (CA: r = - 0.276, p = 0.013, TE: r = 0.311, p = 0.005, PEN: r = 0.241, p = 0.032, NPE: r = 0.250, p = 0.025, DMS: r = 0.235, p = 0.036), but not with the MMSE score. Multiple regression analyses with the stepwise forward selection method including age, ESS score, bedtime, sleep timing, and sleep timing SD, revealed that the ESS score, and sleep timing SD were significant factors related to CA on the WCST (ESS score: ß = - 0.322, p = 0.004; sleep timing SD: ß = - 0.250, p = 0.022). Assessment of sleep-wake rhythms, daytime sleepiness, and cognitive function using the MMSE and WCST is valuable for the prediction of cognitive decline in the geriatric population.

Comparison of Polysomnography, Single-Channel Electroencephalogram, Fitbit, and Sleep Logs in Patients With Psychiatric Disorders: Cross-Sectional Study.

BACKGROUND: Sleep disturbances are core symptoms of psychiatric disorders. Although various sleep measures have been developed to assess sleep patterns and quality of sleep, the concordance of these measures in patients with psychiatric disorders remains relatively elusive. OBJECTIVE: This study aims to examine the degree of agreement among 3 sleep recording methods and the consistency between subjective and objective sleep measures, with a specific focus on recently developed devices in a population of individuals with psychiatric disorders. METHODS: We analyzed 62 participants for this cross-sectional study, all having data for polysomnography (PSG), Zmachine, Fitbit, and sleep logs. Participants completed questionnaires on their symptoms and estimated sleep duration the morning after the overnight sleep assessment. The interclass correlation coefficients (ICCs) were calculated to evaluate the consistency between sleep parameters obtained from each instrument. Additionally, Bland-Altman plots were used to visually show differences and limits of agreement for sleep parameters measured by PSG, Zmachine, Fitbit, and sleep logs. RESULTS: The findings indicated a moderate agreement between PSG and Zmachine data for total sleep time (ICC=0.46; P<.001), wake after sleep onset (ICC=0.39; P=.002), and sleep efficiency (ICC=0.40; P=.006). In contrast, Fitbit demonstrated notable disagreement with PSG (total sleep time: ICC=0.08; wake after sleep onset: ICC=0.18; sleep efficiency: ICC=0.10) and exhibited particularly large discrepancies from the sleep logs (total sleep time: ICC=-0.01; wake after sleep onset: ICC=0.05; sleep efficiency: ICC=-0.02). Furthermore, subjective and objective concordance among PSG, Zmachine, and sleep logs appeared to be influenced by the severity of the depressive symptoms and obstructive sleep apnea, while these associations were not observed between the Fitbit and other sleep instruments. CONCLUSIONS: Our study results suggest that Fitbit accuracy is reduced in the presence of comorbid clinical symptoms. Although user-friendly, Fitbit has limitations that should be considered when assessing sleep in patients with psychiatric disorders.

LPS and its relationship with subjective-objective discrepancies of sleep onset latency in patients with psychiatric disorders.

Subjective-objective discrepancies in sleep onset latency (SOL), which is often observed among psychiatric patients, is attributed partly to the definition of sleep onset. Recently, instead of SOL, latency to persistent sleep (LPS), which is defined as the duration from turning out the light to the first consecutive minutes of non-wakefulness, has been utilized in pharmacological studies. This study aimed to determine the non-awake time in LPS that is most consistent with subjective sleep onset among patients with psychiatric disorders. We calculated the length of non-awake time in 30-s segments from lights-out to 0.5-60 min. The root mean square error was then calculated to determine the most appropriate length. The analysis of 149 patients with psychiatric disorders showed that the optimal non-awake time in LPS was 12 min. On the other hands, when comorbid with moderate or severe obstructive sleep apnea (OSA), the optimal length was 19.5 min. This study indicates that 12 min should be the best fit for the LPS non-awake time in patients with psychiatric disorders. When there is comorbidity with OSA, however, a longer duration should be considered. Measuring LPS minimizes discrepancies in SOL and provides important clinical information.

Feasibility of a wrist-worn wearable device for estimating mental health status in patients with mental illness.

Object: Real-world data from wearable devices has the potential to understand mental health status in everyday life. We aimed to investigate the feasibility of estimating mental health status using a wrist-worn wearable device (Fitbit Sense) that measures movement using a 3D accelerometer and optical pulse photoplethysmography (PPG). Methods: Participants were 110 patients with mental illnesses from different diagnostic groups. The study was undertaken between 1 October 2020 and 31 March 2021. Participants wore a Fitbit Sense on their wrist and also completed the State-Trait Anxiety Inventory (STAI), Positive and Negative Affect Schedule (PANAS), and EuroQol 5 dimensions 5-level (EQ-5D-5L) during the study period. To determine heart rate (HR) variability (HRV), we calculated the sdnn (standard deviation of the normal-to-normal interval), coefficient of variation of R-R intervals, and mean HR separately for each sleep stage and the daytime. The association between mental health status and HR and HRV was analyzed. Results: The following significant correlations were found in the wake after sleep onset stage within 3 days of mental health status assessment: sdnn, HR and STAI scores, HR and PANAS scores, HR and EQ-5D-5L scores. The association between mental health status and HR and HRV was stronger the closer the temporal distance between mental health status assessment and HR measurement. Conclusion: A wrist-worn wearable device that measures PPG signals was feasible for use with patients with mental illness. Resting state HR and HRV could be used as an objective assessment of mental health status within a few days of measurement.

A Study of Factors Causing Sleep State Misperception in Patients with Depression.

Purpose: Sleep state misperception, which is the discrepancy between subjective and objective sleep, is often observed in patients with depression. This phenomenon may delay the remission of depression. Previous studies have focused on the total sleep time (TST) misperception, with many of these studies using actigraphy. Thus, our study investigated depressed patients with the exploratory aim of clarifying factors associated with the sleep state misperception including the wake after sleep onset (WASO) misperception, with their objective sleep additionally evaluated by polysomnography (PSG). Patients and Methods: We conducted a cross-sectional study. Before undergoing overnight PSG monitoring, 40 patients with depression completed questionnaires that included the Beck Depression Inventory (BDI), Epworth sleepiness scale, Temperament and Character Inventory, and the Pittsburgh sleep quality index. Patients were also asked to estimate their subjective sleep duration after they woke up in the morning. Based on this data, we calculated the misperception using the following formula: subjective sleep duration minus objective sleep duration. We compared each factor between negative and positive misperception groups and the multiple regression analysis was performed for TST and WASO misperception, respectively. Results: Although sleep architectures, age, severity of depression and obstructive sleep apnea (OSA) exhibited differences in underestimating or overestimating the WASO, only sex differences were associated with underestimating or overestimating their total sleep time (TST). Moreover, BDI, the severity of OSA, sleep architectures (N1% and N2%), and benzodiazepine (BZD) use were significantly correlated with WASO misperception, whereas only OSA severity was significantly correlated with TST misperception. A subsequent multiple regression analysis demonstrated the BDI was independently correlated with the WASO misperception (ß=0.341, p=0.049). Conclusion: In clinical practice, interventions especially for OSA, and the reduction of depressive symptoms are an important method for improving patient sleep perception. Moreover, current results suggest that BZD prescriptions should be avoided as well.

Prevalence of obstructive sleep apnea as assessed by polysomnography in psychiatric patients with sleep-related problems.

PURPOSE: Patients with psychiatric disorders often complain of sleep disturbances and are frequently suspected of obstructive sleep apnea (OSA). However, data regarding sleep problems evaluated by attended polysomnography (PSG) remain limited in this population. We analyzed the results of attended PSG from psychiatric patients with sleep-related problems to determine the prevalence and features of sleep disorders among this population. METHODS: We retrospectively investigated the attended PSG results of patients with psychiatric disorders: major depressive disorder, bipolar disorder, neurodevelopmental disorder, schizophrenia, neurocognitive disorder, anxiety disorder, somatic symptom disorder. RESULTS: Of 264 patients, 158 men (60%), mean age was 47 ± 19.9 years. More than half of the patients with major depressive disorder (62%), bipolar disorder (70%), schizophrenia (58%), neurocognitive disorders (55%), and somatic symptom disorder (56%) had OSA. Among the psychiatric patients with OSA, 62% of these patients had moderate to severe OSA. The risk factors for OSA were snoring, male, age, and body mass index. The presence of OSA was not associated with the Pittsburgh Sleep Quality Index, Epworth Sleepiness Scale score, or benzodiazepine, antipsychotic, or antidepressant use. Other sleep disorders were insomnia (19%), central disorders of hypersomnia (8%), restless legs syndrome/periodic limb movement of sleep (8%), rapid eye movement sleep behavior disorder (7%), and central sleep apnea syndrome (3%). CONCLUSIONS: PSG revealed that moderate to severe OSA was common in psychiatric patients with or without snoring. Subjective symptoms and psychotropics did not predict OSA. Therefore, PSG is needed to reveal sleep conditions in patients with psychiatric disorders.

Polysomnographic characteristics and predictors of positional obstructive sleep apnea in Japanese elderly.

Sleep problems and obstructive sleep apnea (OSA) increase with age and disturb life in old age. Positional therapy is one option to treat OSA, but the differences in clinical pathophysiology between elderly and other age groups have not been fully investigated. We explored the pathophysiological features of sleep apnea, factors that are independently associated with positional OSA and the prevalence in elderly patients. We studied demographic and polysomnographic data of 85 elderly individuals with OSA (age ≥ 65 years) and 124 non-elderly patients with OSA (age, 20-64 years). The Amsterdam Positional OSA Classification (APOC) was used to evaluate positional OSA. Body mass index (BMI) and Epworth sleepiness scale were both significantly lower in the elderly group than in the non-elderly group, although apnea/hypopnea index (AHI) did not differ between groups. OSA severity affected total sleep time, sleep efficiency, and waking after sleep onset more in the elderly than in the non-elderly. AHI in the lateral position was significantly lower in elderly than in non-elderly, although AHI in the supine position was almost the same between two groups. The distribution of APOC 1 and 2 (lateral sleep effective) was significantly higher in the elderly than in the non-elderly. Relative factors such as BMI, rate of hypopnea, and lowest SpO2 associated with positional OSA in non-elderly groups did not differ significantly among APOC subgroups in elderly patients. Our findings are suggesting that characteristics of the positional OSA is different between elderly and younger-age OSA patients.

FLUID study: study protocol for an open-label, single-centre pilot study to investigate the efFect of Lemborexant on sleep management in Japanese sUbjects aged 50 years and older with Insomnia Disorder.

INTRODUCTION: Bidirectional associations have been reported between sleep disturbance and both cognitive impairment, including Alzheimer's disease and amyloid beta-peptide (Aß) accumulation. These relationships can be explained by the glymphatic system, which acts as a garbage drainage system in the brain. As interstitial fluid dynamics are suggested to increase during sleep, clearance of Aß can be influenced by sleep disturbance or deprivation. We hypothesised that using lemborexant, an orexin receptor antagonist, to improve sleep quality would also improve the function of the glymphatic system. We plan to examine the effect of lemborexant on sleep quality and the glymphatic system among patients with insomnia disorder. METHODS AND ANALYSIS: This pilot study is designed as an open-label, single-arm, single-centre trial. Thirty patients aged 50 years and over with insomnia will be recruited. The participants will take lemborexant (5 mg) at bedtime for 12 weeks and undergo a home-based sleep study at baseline and weeks 4 and 12, as well as MRI examinations to evaluate the glymphatic system at baseline and week 12. The primary outcome will be changes in objective sleep parameters as evaluated using a sleep monitoring system. The secondary outcomes will be changes in subjective sleep parameters. The relationships between changes in sleep parameters and the glymphatic system will be evaluated using diffusion tensor image analysis along the perivascular space, which is called the ALPS-index. Sleep parameters and the ALPS-index will be analysed using a paired t-test or Pearson's correlation coefficient. ETHICS AND DISSEMINATION: The study protocol was approved by Nagoya University Certified Review Board. The findings from this research will be published in peer-reviewed journals and be presented at local, national and international conferences. TRIAL REGISTRATION NUMBER: jRCTs041210024.

Effects of long sleep time and irregular sleep-wake rhythm on cognitive function in older people.

Sleep disturbances and cognitive decline are common in older adults. We aimed to investigate the effects of the total sleep time (TST) and sleep-wake rhythm on executive function and working memory in older adults. In 63 older participants, we measured the TST, wake after sleep onset (WASO), and sleep timing (midpoint between bedtime and wake-up time) using actigraphy. Executive function was evaluated with the trail making test B (TMT-B) and Wisconsin card sorting test (WCST). The number of back task (N-back task) was used to measure working memory. Participants with a TST ≥ 8 h had a significantly lower percentage of correct answers (% correct) on the 1-back task than those with a TST < 8 h. The % correct on the 1-back task was significantly correlated with the TST, WASO, and sleep timing. Multiple regression analyses revealed that the TST and sleep timing were significant factors of the % correct on the 1-back task. The TMT-B score was significantly correlated with the sleep timing. Category achievement on the WCST was significantly correlated with the standard deviation of the sleep timing. Therefore, a long sleep time and an irregular sleep-wake rhythm could have adverse effects on executive function and working memory in older people.

Effects of age and sex on eye movement characteristics.

Abnormal eye movements are often associated with psychiatric disorders. Eye movements are sensorimotor functions of the brain, and aging and sex would affect their characteristics. A precise understanding of normal eye movements is required to distinguish disease-related abnormalities from natural differences associated with aging or sex. To date, there is no multicohort study examining age-related dependency and sex effects of eye movements in healthy, normal individuals using large samples to ensure the robustness and reproducibility of the results. In this study, we aimed to provide findings showing the impact of age and sex on eye movement measures. The present study used eye movement measures of more than seven hundred healthy individuals from three large independent cohorts. We herein evaluated eye movement measures quantified by using a set of standard eye movement tests that have been utilized for the examination of patients with schizophrenia. We assessed the statistical significance of the effects of age and sex and its reproducibility across cohorts. We found that 4-18 out of 35 eye movement measures were significantly correlated with age, depending on the cohort, and that 10 of those, which are related to the fixation and motor control of smooth pursuit and saccades, showed high reproducibility. On the other hand, the effects of sex, if any, were less reproducible. The present results suggest that we should take age into account when we evaluate abnormalities in eye movements.

Sleep fragmentation and working memory in healthy adults.

INTRODUCTION: Sleep is essential for performing cognitive function in humans. We have hypothesized that sleep fragmentation compared to sleep efficiency may have a negative impact on the working memory. MATERIAL AND METHODS: Twenty-eight healthy adults (18 males and 10 females; mean age 27.8±15.5 years) were enrolled in this study. We measured the total sleep time (TST), sleep efficiency, %stage wakefulness (W), %stage rapid eye movement (REM), %stage N1, %stage N2, %stage N3, wake after sleep onset (WASO), and arousal index using polysomnography. Working memory, executive function, and sustained attention of three domains of cognitive function were evaluated with the number of back task (N-back task), Wisconsin card sorting test (WCST), and continuous performance test-identical pairs (CPT-IP), respectively. RESULTS: The percentage of correct answers on the 2-back task was significantly correlated with %stage REM, %stage N1, and %stage N2 (%stage REM: r=0.505, p=0.006; %stage N1: r=-0.637, p<0.001; %stage N2: r=0.670, p<0.001), and multiple regression analysis including the stepwise forward selection method revealed that %stage N2 was the most significant factor (%stage N2: ß=0.670, p<0.001). The percentage of correct answers on the 2-back task was also significantly correlated with TST, sleep efficiency, WASO, and arousal index (TST: r=0.492, p=0.008; sleep efficiency: r=0.622, p<0.001; WASO: r=-0.721, p<0.001; arousal index: r=-0.656, p<0.001), and WASO was the significant factor (ß=-2.086, p=0.007). The WCST category achievement and CPT-IP d-prime score were correlated with none of the sleep variables. CONCLUSION: Increased WASO and a decrease in %stage N2 were associated with worse working memory.

Performance of an ambulatory electroencephalogram sleep monitor in patients with psychiatric disorders.

Key clinical symptoms observed among individuals with psychiatric disorders include difficulty falling asleep or maintaining sleep, poor sleep quality and nightmares. Those suffering from sleep disorders often present with symptoms of discontent with regard to sleep quality, timing and quantity, and these symptoms have an adverse impact on function and quality of life. A minimally invasive technique would be preferable in patients with psychiatric disorders, who tend to be sensitive to environmental change. Accordingly, we evaluated the performance of Zmachine Insight Plus, an ambulatory electroencephalography sleep monitor, in patients with psychiatric disorders. One hundred and three patients undergoing polysomnography were enrolled in this study. Zmachine Insight Plus was performed simultaneously with polysomnography. Total sleep time, sleep efficiency, wake after sleep onset, rapid eye movement (REM) sleep, light sleep (stages N1 and N2) and deep sleep (stage N3) were assessed. Total sleep time, sleep efficiency, wake after sleep onset, REM sleep duration and non-REM sleep duration of Zmachine Insight Plus showed a significant correlation with those of polysomnography. Lower sleep efficiency and increased frequency of waking after sleep onset, the arousal index and the apnea-hypopnea index on polysomnography were significantly associated with the difference in sleep parameters between the two methods. Among patients with psychiatric disorders who are sensitive to environmental change, Zmachine Insight Plus would be a useful technique to objectively evaluate sleep quality.

Patient characteristics affecting accurate detection of sleep apnea using a bed sheet-type portable monitor.

PURPOSE: Although performed inside a laboratory, attended polysomnography (PSG) has long been the gold standard for the diagnosis of sleep apnea. However, high costs and long wait times have led to the development of home-based portable monitoring devices. A bed sheet-shaped device called SD102 (Suzuken Co., Nagoya, Japan) has been developed, and its accuracy in evaluating sleep apnea is becoming evident. The purpose of this study was to confirm the accuracy of SD102 in evaluating sleep apnea and to investigate patient characteristics that may contribute to inaccurate test results in patients with suspected obstructive sleep apnea (OSA). METHODS: One hundred and eighty-nine patients simultaneously underwent PSG and portable monitoring by using a home sleep apnea testing (HSAT) device. A blinded, experienced technologist using the American Academy of Sleep Medicine criteria versions 2.1 and 2.3 scored the PSG data and HSAT device data, respectively. RESULTS: The respiratory event index (REI) by HSAT significantly correlated with the apnea-hypopnea index (AHI) by PSG (r = 0.974, p < 0.001). HSAT sensitivity, specificity, and positive and negative predictive values of 0.99, 0.83, 0.95, and 0.97, respectively. Body mass index and arousal index were significantly associated with the difference between REI from SD102 HSAT and AHI from PSG. CONCLUSIONS: This study demonstrates the good agreement between REI and AHI in patients with suspected OSA and suggests that understanding the limitations of different testing methods may help in the accurate detection of OSA.

Effects of sleep-disordered breathing and hypertension on cognitive function in elderly adults.

Purpose: The prevalence of sleep-disordered breathing (SDB) increases with aging. SDB is a risk of hypertension, and both might lead to cognitive decline. However, the role of SDB and hypertension on the pathogenesis of age-related cognitive decline remains unclear. We examined the effects of these two diseases on cognitive function in elderly adults.Methods: Fifty-two elderly individuals (mean age, 69.6 ± 4.0 years) free from impairment in daily living activities participated in this study. Apnea/hypopnea index (AHI) and minimum oxygen saturation (SpO2) were assessed using a portable home monitoring device. We evaluated excessive daytime sleepiness with the Epworth sleepiness scale (ESS). Cognitive performance was assessed using the Wisconsin card sorting test (WCST), continuous performance test-Identical pairs (CPT-IP), and N-back task. Hypertension and diabetes mellitus were evaluated via questionnaire and blood pressure value.Results: The WCST category achievement was significantly lower in participants with minimum SpO2 <90% than those with minimum SpO2 ≥90%. The percentage of correct answer on the 0- and 1-back tasks was significantly lower in the hypertensives than normotensives. Minimum SpO2 was correlated with category achievement on the WCST. Multiple regression analysis including age, sex, body mass index, AHI, minimum SpO2, ESS, hypertension, and diabetes mellitus revealed that hypertension was the most significant factor for percentage correct answers on the 0- and 1-back tasks. There were no significant correlations between body mass index, ESS or diabetes mellitus and the parameters of WCST, CPT-IP, or N-back tasks.Conclusion: In elderly adults, nocturnal hypoxia and hypertension had a negative effect on cognitive function.

Very low frequency component of heart rate variability as a marker for therapeutic efficacy in patients with obstructive sleep apnea: Preliminary study.

BACKGROUND: Although positive airway pressure (PAP) therapy is effective for treating obstructive sleep apnea (OSA), some patients with severe OSA are intolerable to this treatment, which may lead to an increase in the mortality and morbidity of cardiovascular diseases. We investigated the relationship between heart rate variability (HRV) and sleep parameters during natural sleep and treatment of patients with OSA. MATERIALS AND METHODS: This was the cross-sectional observation study. Patients were 17 males with severe OSA who were unable to accept continuous PAP. Standard polysomnography was performed for two consecutive nights, i.e., during natural sleep and following night with bilevel PAP (BiPAP) treatment. Time-dependent responses of the amplitudes of low frequency (LF), very low frequency (VLF), and high frequency components of HRV were assessed with the technique of complex demodulation. RESULTS: Apnea-hypopnea index, oxygen desaturation time, and percentage of stage 1 sleep were significantly reduced, whereas the percentages of rapid eye movement and stages 3 + 4 sleep were increased, by BiPAP treatment. Therapy also reduced the amplitudes of VLF and LF components of HRV. Difference in amplitudes of VLF during natural sleep and treatment with BiPAP was significantly correlated with difference in percentages of stage 1 and stages 3 + 4 sleep. CONCLUSION: Therapy-induced amelioration of OSA and sleep quality was accompanied by decrease in the amplitudes of VLF components of HRV. The VLF component may thus reflect physiological changes in both autonomic activity and sleep structure and serve as an objective marker for therapeutic efficacy in patients with severe OSA.

Clinical profiles of late-onset psychiatric patients exhibiting incidental REM sleep without atonia.

Rapid eye movement (REM) sleep without atonia (RWA), which is a hallmark of REM sleep behavior disorder (RBD) on polysomnography (PSG), may represent specific characteristics of prodromal Parkinson's disease (PD)/dementia with Lewy bodies (DLB), even when dream-enactment behavior is absent. We investigated the clinical profiles associated with PD/DLB in late-onset psychiatric patients exhibiting incidental RWA. Among patients who underwent PSG in our psychiatric ward, eight with incidental RWA, nine with idiopathic RBD, and seven with PD or DLB who had preceding RBD were included. Clinical variables, including the percentage of RWA in the total REM sleep (%RWA), were compared among the three groups. The frequency of depressive disorders as a primary psychiatric diagnosis and antidepressant usage were significantly higher in the incidental RWA group than in the other groups. There were no differences in the prevalence of supportive features of DLB among the three groups. The median %RWA was significantly lower in the incidental RWA group than in the other groups. Although the cardiac 123I-metaiodobenzylguanidine uptake was significantly higher in the incidental RWA group compared with the other groups, the groups showed overlap in the specific binding ratios on dopamine transporter imaging. All patients in the three groups exhibited cingulate island sign ratios on brain perfusion single-photon emission computed tomography within a threshold of 0.281, which is the optimal cut-off value for a diagnosis of DLB. In this series, late-onset psychiatric patients with incidental RWA partially shared common clinical profiles with idiopathic RBD and PD/DLB.