Increasing and high prevalence of moderate to severe obstructive sleep apnea in acute ischemic stroke in Taiwan.

STUDY OBJECTIVES: The prevalence of obstructive sleep apnea (OSA) after stroke is variable, likely due to the time of examination and patient population. Although risk factors for OSA are well established, those for OSA in patients with ischemic stroke have not yet been fully identified. Therefore, we examined the prevalence of OSA and identified risk factors for OSA in the acute stage of ischemic stroke in the Taiwanese population. METHODS: A total of 103 patients with acute ischemic stroke were screened for OSA by performing polysomnography. The demographic and clinical data, Epworth Sleepiness Scale score, and other stroke risk factors were recorded. Sleep parameters, namely sleep efficiency, sleep stages, apnea-hypopnea index, and oxygen desaturation index were recorded. Logistic regression analysis was conducted to determine clinical and demographic risk factors for moderate to severe OSA in patients with stroke. RESULTS: We determined that 91.2% of the patients had OSA in the acute stage of ischemic stroke, and 70% of the patients had moderate to severe OSA. Multivariate logistic regression analysis revealed that patients aged ≥65 years had a significantly higher risk of moderate to severe OSA (adjusted OR: 3.04, 95% CI: 1.20-7.69, p < 0.05) compared with patients with ischemic stroke aged <50 years. CONCLUSION: OSA is highly prevalent among patients with ischemic stroke in the acute stage, and those aged ≥65 years had a significantly increased risk of moderate to severe OSA. In clinical practice, routine PSG screening of OSA may be necessary among older patients with stroke.

Association between subclinical epileptiform discharge and the behavioral and psychological symptoms in patients with Alzheimer's dementia.

OBJECTIVES: Behavioral and psychological symptoms of dementia (BPSD) are highly prevalent in patients with Alzheimer's disease (AD), causing burdens on caregivers. Behavioral and psychological symptoms of dementia and subclinical epileptiform discharge (SED) increased with the disease course of AD. However, the interaction between them was still unknown. The present study aimed to evaluate the associations between SED and BPSD. METHODS/DESIGN: Patients with AD from Kaohsiung Municipal Ta-tung Hospital were included in this study. International 10-20 system scalp electroencephalography (EEG) for 13 min was performed to detect SED. Behavioral and psychological symptoms of dementia was assessed by neuropsychiatric inventory (NPI) questionnaires. The occurrence of BPSD subsyndromes was compared between patients with and without SED. RESULTS: Two hundred sixty-three adult patients qualified for the inclusion criteria and were enrolled in this study. The mean age of patients was 80.2 years, and approximately 62% were women. 17.1% of patients showed SED on EEG. Apathy was the most commonly reported BPSD subsyndrome in this cohort. There was no significant difference in the prevalence of BPSD between patients with and without SED. (75.6% vs. 67.4%, p = 0.2806). However, the NPI score of irritability subsyndrome was significantly higher in the SED (+) group (2.6 ± 3.7 vs. 1.2 ± 2.7, p = 0.0028). In addition, subclinical epileptiform discharge in the frontal lobe was associated with a considerably higher occurrence of hyperactivity subsyndrome, including irritability. CONCLUSIONS: SED may not be a direct cause of BPSD, but the presence of SED may affect the manifestation of BPSD.

The efficacy of exogenous melatonin supplement in ameliorating irritable bowel syndrome severity: A meta-analysis of randomized controlled trials.

BACKGROUND: Irritable bowel syndrome (IBS) was found in 11% of the general population worldwide. The current pharmacologic management of IBS was unsatisfactory, and it was accompanied by a number of adverse events. Melatonin was found to play an important role in gastrointestinal smooth muscle motility. Dysregulation of endogenous melatonin secretion has been found in IBS patients. Exogenous melatonin supplement has become one alternative treatment for IBS, but the evidence is inconclusive. The current meta-analysis sought to determine the efficacy of exogenous melatonin supplement in improving IBS severity in IBS patients. METHODS: We included randomized controlled trials (RCTs) that investigated the efficacy of exogenous melatonin supplement in ameliorating IBS severity in IBS patients. This meta-analysis was conducted using a random effects model. The primary target outcomes were changes in IBS severity associated with melatonin or placebo. RESULTS: This meta-analysis of 4 RCTs and 115 participants revealed that exogenous melatonin supplement was associated with significantly better improvement in overall IBS severity than placebo (k = 4, Hedges' g = 0.746, 95% confidence intervals = 0.401-1.091, p < 0.001). The subgroup without concurrent medication had the same result (p < 0.001). In addition, exogenous melatonin supplement was also associated with significantly better improvement in IBS pain severity (p < 0.001) and quality of life (p = 0.007) than placebo, but not in abdominal distension (p = 0.111) or sleep quality (p = 0.142). Finally, melatonin was associated with similar safety profiles with placebo. CONCLUSION: This meta-analysis provides evidence for the use of exogenous melatonin in IBS patients to ameliorate overall IBS severity, IBS pain severity, and quality of life. TRIAL REGISTRATION: PROSPERO CRD42021269451.

The association of changes of sleep architecture related to donepezil: A systematic review and meta-analysis.

BACKGROUND: Donepezil had been recognized to have impact on sleep quality in demented patients. However, there was insufficient evidences about the actual effect of donepezil in the sleep architectures. Our meta-analysis aimed to evaluate the changes of sleep architectures related to donepezil use. METHODS: Followed the PRISMA2020 and AMSTAR2 guidelines, electronic search had been performed on the databases of PubMed, Embase, ScienceDirect, ClinicalKey, Cochrane CENTRAL, ProQuest, Web of Science, and ClinicalTrials.gov. The outcome measurement was changes of sleep parameters detected by polysomnography. A random-effects meta-analysis was conducted. RESULTS: Total twelve studies had been involved. The percentage of REM sleep would significantly increase after donepezil treatment (Hedges' g = 0.694, p < 0.001). Compared to placebo/controls, subjects with donepezil would had significantly increased percentage of REM sleep stage (Hedges' g = 0.556, p = 0.018). Furthermore, donepezil was also associated with the decreased stage 2 sleep percentage, sleep efficiency, or total sleep time in different analysis conditions. CONCLUSION: Our meta-analysis provided detailed changes of sleep architectures related to donepezil treatment. Further larger sample size studies with stricter control of potential moderators are needed to clarify these issues.

Activation of acid-sensing ion channel 3 by lysophosphatidylcholine 16:0 mediates psychological stress-induced fibromyalgia-like pain.

OBJECTIVES: Fibromyalgia is commonly considered a stress-related chronic pain disorder, and daily stressors are known triggers. However, the relation between stress and pain development remains poorly defined by clinical approaches. Also, the aetiology remains largely unknown. METHODS: We used a newly developed mouse model and lipidomic approaches to probe the causation and explore the biological plausibility for how perceived stress translates into chronic non-inflammatory pain. Clinical and lipidomic investigations of fibromyalgia were conducted for human validation. RESULTS: Using non-painful sound stimuli as psychological stressors, we demonstrated that mice developed long-lasting non-inflammatory hyperalgesia after repeated and intermittent sound stress exposure. Elevated serum malondialdehyde level in stressed mice indicated excessive oxidative stress and lipid oxidative damage. Lipidomics revealed upregulation of lysophosphatidylcholine 16:0 (LPC16:0), a product of lipid oxidisation, in stressed mice. Intramuscular LPC16:0 injection triggered nociceptive responses and a hyperalgesic priming-like effect that caused long-lasting hypersensitivity. Pharmacological or genetic inhibition of acid-sensing ion channel 3 impeded the development of LPC16:0-induced chronic hyperalgesia. Darapladib and antioxidants could effectively alleviate the stress-induced hyperalgesia by inhibiting LPC16:0 synthesis. Clinical investigations showed that excessive oxidative stress and LPC16:0 expression also exist in patients with fibromyalgia. Moreover, LPC16:0 expression was correlated with pain symptoms in patients with high oxidative stress and disease severity. CONCLUSIONS: Our study provides experimental evidence for the causal effect of psychological stressors on chronic pain development. The findings identify a possible pathophysiological mechanism of stress-induced chronic non-inflammatory pain at molecular, behavioural and clinical levels that might indicate a new therapeutic approach for fibromyalgia.

THE ASSOCIATION BETWEEN CENTRAL SEROUS CHORIORETINOPATHY AND SLEEP APNEA: A Nationwide Population-Based Study.

PURPOSE: To identify the association between sleep apnea (SA) and central serous chorioretinopathy (CSC). METHODS: In this nationwide population-based study using the Taiwan National Health Insurance Database, we enrolled adult patients with a diagnosis of SA and matched each patient to 30 age- and gender-matched control subjects without any SA diagnosis. Using Poisson regression analyses, the incidence rate of CSC was compared between SA patients and control subjects. RESULTS: A total of 10,753 SA patients and 322,590 control subjects were identified. After adjusting for age, gender, residency, income level, and comorbidities, the incidence rate of CSC was significantly higher in SA patients than in the control subjects (adjusted incident rate ratio for probable SA: 1.2 [95% CI: 1.1-1.4], P < 0.0001). Analyses of the propensity score-matched subpopulations also confirmed our findings. Risk factors for CSC in SA patients included male gender, age ≤50 years, higher income, presence of heart disease, absence of chronic pulmonary disease, and presence of liver disease. In SA patients, those who had received continuous positive airway pressure titration had a significantly lower incidence rate of CSC than the others. CONCLUSION: Our study revealed a significantly higher incidence rate of CSC in SA patients compared with the control subjects.

Peroxisome Proliferator-Activated Receptor γ Coactivator 1α Activates Vascular Endothelial Growth Factor That Protects Against Neuronal Cell Death Following Status Epilepticus through PI3K/AKT and MEK/ERK Signaling.

Status epilepticus may cause molecular and cellular events, leading to hippocampal neuronal cell death. Peroxisome proliferator-activated receptor γ coactivator 1-α (PGC-1α) is an important regulator of vascular endothelial growth factor (VEGF) and VEGF receptor 2 (VEGFR2), also known as fetal liver kinase receptor 1 (Flk-1). Resveratrol is an activator of PGC-1α. It has been suggested to provide neuroprotective effects in epilepsy, stroke, and neurodegenerative diseases. In the present study, we used microinjection of kainic acid into the left hippocampal CA3 region in Sprague Dawley rats to induce bilateral prolonged seizure activity. Upregulating the PGC-1α pathway will increase VEGF/VEGFR2 (Flk-1) signaling and further activate some survival signaling that includes the mitogen activated protein kinase kinase (MEK)/mitogen activated protein kinase (ERK) and phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT) signaling pathways and offer neuroprotection as a consequence of apoptosis in the hippocampal neurons following status epilepticus. Otherwise, downregulation of PGC-1α by siRNA against pgc-1α will inhibit VEGF/VEGFR2 (Flk-1) signaling and suppress pro-survival PI3K/AKT and MEK/ERK pathways that are also accompanied by hippocampal CA3 neuronal cell apoptosis. These results may indicate that the PGC-1α induced VEGF/VEGFR2 pathway may trigger the neuronal survival signaling, and the PI3K/AKT and MEK/ERK signaling pathways. Thus, the axis of PGC-1α/VEGF/VEGFR2 (Flk-1) and the triggering of downstream PI3K/AKT and MEK/ERK signaling could be considered an endogenous neuroprotective effect against apoptosis in the hippocampus following status epilepticus.

Helicobacter pylori cholesterol glucosylation modulates autophagy for increasing intracellular survival in macrophages.

Cholesterol-α-glucosyltransferase (CGT) encoded by the type 1 capsular polysaccharide biosynthesis protein J (capJ) gene of Helicobacter pylori converts cellular cholesterol into cholesteryl glucosides. H. pylori infection induces autophagy that may increase bacterial survival in epithelial cells. However, the role of H. pylori CGT that exploits lipid rafts in interfering with autophagy for bacterial survival in macrophages has not been investigated. Here, we show that wild-type H. pylori carrying CGT modulates cholesterol to trigger autophagy and restrain autophagosome fusion with lysosomes, permitting a significantly higher bacterial burden in macrophages than that in a capJ-knockout (∆CapJ) mutant. Knockdown of autophagy-related protein 12 impairs autophagosome maturation and decreases the survival of internalised H. pylori in macrophages. These results demonstrate that CGT plays a crucial role in the manipulation of the autophagy process to impair macrophage clearance of H. pylori.

Periodic limb movements during sleep are associated with cardiovascular diseases: A systematic review and meta-analysis.

Periodic limb movements during sleep present with repetitive movements, typically in the lower limbs, during sleep. Periodic limb movements during sleep have been proposed to be associated with increased risk of heart diseases. The aim of this study was to examine the co-morbidity rates of heart disease, including acute myocardial infarction, coronary artery disease and cardiovascular disease, in subjects with or without periodic limb movements during sleep through a meta-analysis. An electronic review of PubMed, Embase, ScienceDirect, Cochrane Library, ProQuest, Web of Science, ClinicalKey and ClinicalTrials.gov was performed. Clinical studies, case-controlled trials and cohort studies were all included in the search. Case reports or series, and non-clinical studies were excluded. A meta-analysis of the results of six studies comparing the prevalence of coronary artery disease/acute myocardial infarction/cardiovascular disease in subjects with/without periodic limb movements during sleep was performed. There were significantly higher co-morbidity rates of coronary artery disease (odds ratio = 1.568, 95% confidence interval: 1.187-2.073, p = 0.002) and cardiovascular disease (odds ratio = 1.279, 95% confidence interval: 1.095-1.494, p = 0.002), but not acute myocardial infarction (odds ratio = 1.272, 95% confidence interval = 0.942-1.718, p = 0.117), in the periodic limb movements during sleep group than in the non-periodic limb movements during sleep group. This meta-analysis highlights the importance of a significantly high prevalence of coronary artery disease and cardiovascular disease in subjects with periodic limb movements during sleep. Further studies should be focused on the potential pathophysiology, and whether treatment for periodic limb movements during sleep can improve the outcome of heart disease.

Sirtuin 1 Regulates Mitochondrial Biogenesis and Provides an Endogenous Neuroprotective Mechanism Against Seizure-Induced Neuronal Cell Death in the Hippocampus Following Status Epilepticus.

Status epilepticus may decrease mitochondrial biogenesis, resulting in neuronal cell death occurring in the hippocampus. Sirtuin 1 (SIRT1) functionally interacts with peroxisome proliferator-activated receptors and γ coactivator 1α (PGC-1α), which play a crucial role in the regulation of mitochondrial biogenesis. In Sprague-Dawley rats, kainic acid was microinjected unilaterally into the hippocampal CA3 subfield to induce bilateral seizure activity. SIRT1, PGC-1α, and other key proteins involving mitochondrial biogenesis and the amount of mitochondrial DNA were investigated. SIRT1 antisense oligodeoxynucleotide was used to evaluate the relationship between SIRT1 and mitochondrial biogenesis, as well as the mitochondrial function, oxidative stress, and neuronal cell survival. Increased SIRT1, PGC-1α, and mitochondrial biogenesis machinery were found in the hippocampus following experimental status epilepticus. Downregulation of SIRT1 decreased PGC-1α expression and mitochondrial biogenesis machinery, increased Complex I dysfunction, augmented the level of oxidized proteins, raised activated caspase-3 expression, and promoted neuronal cell damage in the hippocampus. The results suggest that the SIRT1 signaling pathway may play a pivotal role in mitochondrial biogenesis, and could be considered an endogenous neuroprotective mechanism counteracting seizure-induced neuronal cell damage following status epilepticus.

Resveratrol Promotes Mitochondrial Biogenesis and Protects against Seizure-Induced Neuronal Cell Damage in the Hippocampus Following Status Epilepticus by Activation of the PGC-1α Signaling Pathway.

Peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α) is known to regulate mitochondrial biogenesis. Resveratrol is present in a variety of plants, including the skin of grapes, blueberries, raspberries, mulberries, and peanuts. It has been shown to offer protective effects against a number of cardiovascular and neurodegenerative diseases, stroke, and epilepsy. This study examined the neuroprotective effect of resveratrol on mitochondrial biogenesis in the hippocampus following experimental status epilepticus. Kainic acid was microinjected into left hippocampal CA3 in Sprague Dawley rats to induce bilateral prolonged seizure activity. PGC-1α expression and related mitochondrial biogenesis were investigated. Amounts of nuclear respiratory factor 1 (NRF1), mitochondrial transcription factor A (Tfam), cytochrome c oxidase 1 (COX1), and mitochondrial DNA (mtDNA) were measured to evaluate the extent of mitochondrial biogenesis. Increased PGC-1α and mitochondrial biogenesis machinery after prolonged seizure were found in CA3. Resveratrol increased expression of PGC-1α, NRF1, and Tfam, NRF1 binding activity, COX1 level, and mtDNA amount. In addition, resveratrol reduced activated caspase-3 activity and attenuated neuronal cell damage in the hippocampus following status epilepticus. These results suggest that resveratrol plays a pivotal role in the mitochondrial biogenesis machinery that may provide a protective mechanism counteracting seizure-induced neuronal damage by activation of the PGC-1α signaling pathway.

Cerebrovascular Accident Risk in a Population with Periodic Limb Movements of Sleep: A Preliminary Meta-Analysis.

BACKGROUND AND PURPOSE: Periodic limb movements of sleep (PLMS) are usually comorbid with hypertension, tachycardia, and coronary arterial diseases, which are also risk factors for cerebrovascular accidents (CVA). However, evidence about the relationship between CVA and PLMS is still weak. The aim of this study was to investigate (1) the prevalence of CVA in patients with PLMS, and (2) the severity of PLMS in patients with or without CVA through a meta-analysis. METHODS: The electronic databases of PubMed, Embase, ScienceDirect, ClinicalKey, Cochrane Library, ProQuest, Web of Science, and ClinicalTrials.gov were searched. The inclusion criteria were (1) articles investigating comorbidity between PLMS and CVA, and (2) clinical trials in humans. RESULTS: This meta-analysis included (1) 9,823 patients with PLMS and 9,416 controls from 5 studies to analyze the prevalence of CVA in PLMS, and (2) 158 patients with PLMS with CVA and 88 PLMS controls without CVA from 3 studies to analyze the severity of PLMS with and without CVA. The results showed (1) significantly higher comorbidity rates of CVA in the patients with PLMS than in the controls without PLMS (OR 1.267, p = 0.019), and (2) higher PLM index in the patients with CVA than in the controls (Hedges' g = 0.860, p = 0.001; means difference: 4.435, p = 0.016). CONCLUSIONS: The results revealed (1) a worse severity of PLMS in the patients with CVA, and (2) increased prevalence of CVA in the patients with PLMS. Based on our results, the patients had a higher prevalence of CVA within 8 years of a diagnosis of PLMS compared to those without PLMS by about 1.3-fold. Whether (1) patients with PLMS receiving treatment have a similar incidence of stroke to those without PLMS, and (2) secondary stroke prevention can lower the severity of PLMS or whether those with severe PLMS have a higher risk of stroke is still inconclusive. Future studies investigating the prevalence of CVA in patients with PLMS should use a follow-up period of over 8 years.

Basal sympathetic predominance in periodic limb movements in sleep after continuous positive airway pressure.

PURPOSE: This study investigated the basal autonomic regulation in patients with obstructive sleep apnea (OSA) showing periodic limb movements in sleep (PLMS) emerging after therapy with continuous positive airway pressure (CPAP). METHODS: Data of patients with OSA undergoing a first polysomnography for diagnosis and a second polysomnography for therapy with CPAP were reviewed. Patients with OSA showing PLMS on the first polysomnography were excluded. By using heart rate variability analysis, epochs without any sleep events and continuous effects from the second polysomnography were retrospectively analyzed. RESULTS: Of 125 eligible patients, 30 with PLMS after therapy with CPAP (PLMS group) and 30 not showing PLMS on both polysomnography (non-PLMS group) were randomly selected for the analysis. No significant differences in the demographic characteristics and variables of polysomnographies were identified between the groups. Although one trend of low root mean square of successive differences (RMSSD) between intervals of adjacent normal heart beats (NN intervals) in the PLMS group was observed, patients in the PLMS group had significantly low normalized high-frequency (n-HF) and high-frequency (HF) values, but high normalized low frequency (n-LF) and high ratio of LF to HF (LF/HF ratio). After adjustment for confounding variables, PLMS on the second polysomnography was significantly associated with RMSSD (ß = - 6.7587, p = 0.0338), n-LF (ß = 0.0907, p = 0.0148), n-HF (ß = - 0.0895, p = 0.0163), log LF/HF ratio (ß = 0.4923, p = 0.0090), and log HF (ß = - 0.6134, p = 0.0199). CONCLUSIONS: Patients with OSA showing PLMS emerging after therapy with CPAP may have a basal sympathetic predominance with potential negative cardiovascular effects.

Is one day off sufficient for re-adaptation to a daytime routine after two consecutive nights of work?

Fast rotation three-shift working schedules are common in the medical field in Taiwan. This study investigated whether 24 h off is sufficient for re-adaptation to a daytime routine after working two night shifts (NSs) by comparing changes in cognitive function, anxiety state and objectively measured sleep propensity between those working two NSs followed by 24 h off (n = 21, 2NS-off) and an off-duty group (n = 21, OD). The results showed that nurses in the 2NS-off group were less alert and had decreased visual attention performance and executive function ability than the OD group during the daytime. One day off appeared to be insufficient to adapt back to a daytime shift after two NSs. Further studies are warranted to investigate whether a longer sequence of consecutive NSs (e.g. four NSs) followed by two days off is suitable for a fast rotation three-shift work schedule to allow for optimal performance throughout the next daytime shift. Practitioner Summary: The medical field in Taiwan mandates at least 24 h off between night and day shifts, but this appears to be insufficient for re-adapting to a daytime shift after two night shifts. A longer sequence of consecutive night shifts followed by two days off may be more suitable.

Four Night Shifts Have a Degree of Performance Adaptation.

OBJECTIVE: In this case control study, we investigated the process of adaptation to night shift (NS) work and recovery back to a day schedule among nurses working a fast-rotation three-shift schedule. BACKGROUND: There is limited knowledge of how specific patterns of a fast-rotation shift affect nurses' performance. METHOD: The cognitive performance of off-duty nurses (OD; n = 21), those working the first night of an NS (1NS; n = 21) and the last night of two ( n = 21), three ( n = 20), and four (4NS; n = 21) successive NSs were compared. Changes in sleep propensity, cognitive function, and anxiety were compared in the daytime after working four successive NSs followed by 24 hr off (4NS-off; n = 18) and in those off duty. RESULTS: The visual attention task (VAT) of cognitive function was significantly worse in the 1NS group and significantly better on the last night in the 4NS group than in the other NS groups. The nurses in the 4NS-off group were less alert and had poorer VAT performance than the OD group during the daytime. CONCLUSION: The nurses working on NS experienced a decrease in VAT performance due to acute changes in circadian rhythm but also significant performance adaptation after four consecutive NSs. One off-duty day was insufficient to recover back to a daytime shift after four consecutive NSs. APPLICATION: In a fast-rotation three-shift schedule, performance adaptation occurred in the nurses who worked four consecutive NSs, and more than one off-duty day are needed to recover back to daytime shift after those NSs.

Basal sympathetic predominance in periodic limb movements in sleep with obstructive sleep apnea.

Because the impact of periodic limb movements in sleep (PLMS) is controversial, no consensus has been reached on the therapeutic strategy for PLMS in obstructive sleep apnea (OSA). To verify the hypothesis that PLMS is related to a negative impact on the cardiovascular system in OSA patients, this study investigated the basal autonomic regulation by heart rate variability (HRV) analysis. Sixty patients with mild-to-moderate OSA who underwent polysomnography (PSG) and completed sleep questionnaires were analysed retrospectively and divided into the PLMS group (n = 30) and the non-PLMS group (n = 30). Epochs without any sleep events or continuous effects were evaluated using HRV analysis. No significant difference was observed in the demographic data, PSG parameters or sleep questionnaires between the PLMS and non-PLMS groups, except for age. Patients in the PLMS group had significantly lower normalized high frequency (n-HF), high frequency (HF), square root of the mean of the sum of the squares of difference between adjacent NN intervals (RMSSD) and standard deviation of all normal to normal intervals index (SDNN-I), but had a higher normalized low frequency (n-LF) and LF/HF ratio. There was no significant difference in the Epworth Sleepiness Scale, the Pittsburgh Sleep Quality Index, the Short-Form 36 and the Hospital Anxiety and Depression Scale between the two groups. After adjustment for confounding variables, PLMS remained an independent predictor of n-LF (ß = 0.0901, P = 0.0081), LF/HF ratio (ß = 0.5351, P = 0.0361), RMSSD (ß = -20.1620, P = 0.0455) and n-HF (ß = -0.0886, P = 0.0134). In conclusion, PLMS is related independently to basal sympathetic predominance and has a potentially negative impact on the cardiovascular system of OSA patients.

More severe hypoxemia is associated with better subjective sleep quality in obstructive sleep apnea.

BACKGROUND: Perceived sleep quality may play an important role in diagnosis and therapy for obstructive sleep apnea (OSA). However, few studies have assessed factors that are associated with perceived sleep quality in OSA patients. Hypoxemia depresses the central nervous system and attenuates the perceived respiratory load in asthmatic patients. This study aimed to investigate the factors related to perceived sleep quality, focusing on the role of hypoxemia. METHODS: Polysomnography studies of 156 OSA patients were reviewed. Traditional polysomnographic parameters, including parameters of oxy-hemoglobin saturation (SpO2), were calculated, and the sleep questionnaire and scales were used. Considering the possible pitfalls of absolute values of SpO2 and individualized responses to hypoxemia, the amplitude of desaturation was further computed as "median SpO2 minus lowest 5 % SpO2 "and "highest 5 % SpO2 minus median 5 % SpO2". Correlations between these parameters and perceived sleep quality, represented as the Pittsburgh sleep quality index (PSQI), were performed. Multiple linear regression analysis was also conducted to investigate the factors associated with the PSQI. RESULTS: Although the PSQI was not correlated with the apnea-hypopnea index (r = -0.113, p = 0.162) and oxygen desaturation index (r = -0.085, p = 0.291), the PSQI was negatively correlated with "median SpO2 minus lowest 5 % SpO2" (r = -0.161, p = 0.045). After adjusting for age, total sleep time, the periodic limb movements index, tendency of depression, and the lowest 5 % SpO2, the "median SpO2 minus lowest SpO2" was still a significant predictor for a lower PSQI (ß = -0.357, p = 0.015). CONCLUSIONS: More severe hypoxemia is associated with better perceived sleep quality among OSA patients. This paradox may be associated with hypoxemia-related impairment of perception. The effect of hypoxemia did not appear to be significant in relatively mild hypoxemia but become significant in severe hypoxemia." Median SpO2 minus lowest 5 % SpO2" may also be a better predictor of perceived sleep quality than the apnea-hypopnea index because of the disproportionate effects of hypoxemia. Additionally, further studies are necessary to confirm the role of hypoxemia on perceived sleep quality and identify the possible threshold of hypoxemia in OSA patients.

Rotating night shifts too quickly may cause anxiety and decreased attentional performance, and impact prolactin levels during the subsequent day: a case control study.

BACKGROUND: We investigated circadian changes and effects on mood, sleep-related hormones and cognitive performance when nurses worked consecutive night shifts in a rapidly rotating shift system. Daytime cognitive function, sleep propensity and sleep-related hormones (growth hormone, cortisol, prolactin, thyrotropin) were compared after participants worked two and four consecutive night shifts. METHODS: Twenty-three off-duty nurses, 20 nurses working two consecutive night shifts and 16 nurses working four consecutive night shifts were enrolled. All participants completed the Maintenance of Wakefulness Test, State-Trait Anxiety Inventory, Stanford Sleepiness Scale, visual attention tasks (VAT), Wisconsin Card Sorting Test, and modified Multiple Sleep Latency Test. Hormone levels were also measured four times throughout the day, at 2-h intervals. RESULTS: During the day, the participants in the night shift groups were less able to maintain wakefulness, had poor performance on VAT, and higher thyrotropin levels than did those in the off-duty group. Participants who worked two night shifts were better able to maintain wakefulness, had higher anxiety scale scores, poorer initial performance and lack of learning effect on VAT, and higher prolactin levels compared with those who worked four night shifts. There were no differences in cortisol levels between the two- and four- shift groups. CONCLUSIONS: Rotating night shifts too quickly may cause anxiety and decreased attentional performance, and may impact daytime prolactin levels after night shifts. It is possible that the two-shift group had a higher cortisol level than did the four-shift group, which would be consistent with the group's higher state anxiety scores. The negative findings may be due to the small sample size. Further studies on the effects of consecutive night shifts on mood and cortisol levels during the daytime after sleep restriction would be valuable.