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Cardiovascular function is related to age, sex, and state of consciousness. We hypothesized that cardiovagal baroreflex sensitivity (BRS) demonstrates different patterns in both sexes before and after 50 years of age and that these patterns are associated with patterned changes during the sleep–wake cycle. We recruited 67 healthy participants (aged 20–79 years; 41 women) and divided them into four age groups: 20–29, 30–49, 50–69, and 70–79 years. All the participants underwent polysomnography and blood pressure measurements. For each participant, we used the average of the arterial pressure variability, heart rate variability (HRV), and BRS parameters during the sleep–wake stages. BRS and HRV parameters were significantly negatively correlated with age. The BRS indexes were significantly lower in the participants aged ≥ 50 years than in those aged

Background The diagnosis of acute mountain sickness, which lacks a reliable and objective diagnostic tool, still depends on the clinical symptoms and signs and remains a major threat and unpredictable disease affecting millions of mountaineers. Objectives To record electroencephalography signals with small, convenient, wireless equipment and to test whether electroencephalography parameters, which are more sensitive and reliable markers, could predict the symptoms of acute mountain sickness. Methods Twenty-five participants were enrolled and separated into two groups to climb Mount Jade in Taiwan. We collected electrocardiography signals and arterial oxygen saturation data at ground, moderate (2,400 m), and high altitude (3,400 m). A spectral analysis of the electrocardiography was performed to assess the study subjects’ electroencephalography activity at different frequencies (α, β, θ, δ) and the mean power frequency of electrocardiography. The clinical symptoms and Lake Louise Acute Mountain Sickness scores of the subjects were recorded for comparison. Results A significant change in the δ power of electroencephalography was recorded in subjects ascending from the ground to a high altitude of 3,400 m in a 4-day itinerary. In addition, between the two groups of subjects with and without acute mountain sickness (Lake Louise Acute Mountain Sickness scores < 3 and ≥ 3), the δ power of electroencephalography at the fronto-parietal 1 and parietal 3 electrodes at moderate altitude as well as the changes of δ power and mean power frequency of electrocardiography over parietal 4 at high altitude showed a significant difference. At moderate altitude, the increasing δ power of electroencephalography at the parietal 4 electrode was related to the headache symptom of acute mountain sickness before ascending to high altitude. Conclusion At moderate altitude, the δ power increase of electroencephalography at the P4 electrode could be a predictor of acute mountain sickness symptoms before ascending to high altitude. Thus, electroencephalography had the potential to identify the risk of acute mountain sickness.

Recent animal studies have supported that Lactobacillus plantarum PS128 (PS128) can reduce the severity of anxiety and depression. However, previous studies did not focus on the sleep quality and mood of humans. This study determines whether PS128 reduces the severity of anxiety and depressive symptoms, regulates autonomic nervous system function, and improves sleep quality. Forty participants between 20 and 40 years of age with self-reported insomnia were randomly assigned to two groups, a PS128 group and a placebo group, in a double-blind trial. Participants took two capsules of either PS128 or a placebo after dinner for 30 days. Study measures included subjective depressive symptoms, anxiety and sleep questionnaires, and miniature-polysomnography recordings at baseline and on the 15th and 30th days of taking capsules. Overall, all outcomes were comparable between the two groups at baseline and within the 30-day period, yet some differences were still found. Compared to the control group, the PS128 group showed significant decreases in Beck Depression Inventory-II scores, fatigue levels, brainwave activity, and awakenings during the deep sleep stage. Their improved depressive symptoms were related to changes in brain waves and sleep maintenance. These findings suggest that daily administration of PS128 may lead to a decrease in depressive symptoms, fatigue level, cortical excitation, and an improvement in sleep quality during the deep sleep stage. Daily consumption of PS128 as a dietary supplement may improve the depressive symptoms and sleep quality of insomniacs, although further investigation is warranted.

One recent study showed that atomoxetine-oxybutynin combination (AOC) use is effective in reducing obstructive sleep apnea (OSA) severity. We used a nationwide database to examine the association between AOC use and the risk of OSA incidence. This retrospective cohort study used Taiwan’s National Health Insurance Research Database between the years 2000 and 2015. The patients who used atomoxetine or oxybutynin were included as an exposed cohort. The exposed and unexposed groups were selected in a ratio of 1:3 with sex, age, and index year matching. We used the multivariate Cox proportional regression model to evaluate the association between AOC use and the risk of an incident diagnosis of OSA. The incidence rates of OSA in the exposed cohort (N = 8940) and the unexposed cohort (N = 26,820), were 21.92 and 22.93 per 100,000 person-years, respectively. The adjusted hazard ratio of oxybutynin use only and AOC with a treatment duration of ≥ 366 days were 0.307 (95% CI 0.204–0.995, P = 0.045) and 0.299 (95% CI 0.102–0.933, P = 0.002), respectively. Long-term atomoxetine-oxybutynin combination therapy may be beneficial to reduce the risk of obstructive sleep apnea. Further studies to examine these mechanisms are warranted.

Seizure is a common complication in a neurological intensive care unit (NICU) and it requires continuous electroencephalograms (EEG) monitoring. Implementation of EEG for each bed in a NICU is very expensive and require labor work for interpretation of EEG. To provide an affordable device of EEG in NICU, we developed a low-cost wireless biosensor, which utilized the current standard of the internet of things technology (IoT). In this study, we implement a wireless biosensor for continuous EEG monitoring in NICU and discuss its feasibility. To provide a low-cost EEG device, we embraced Bluetooth and mobile phone technology, which is convenient for implementation. We build a two-channel EEG biosensor, which utilizes Bluetooth to transmit the signal to mobile phones. Then, mobile phones use Wi-Fi technology to send data to the server. Additionally, we also developed a registry to organize the patient's EEG data. In six months research period, we have 65.8% of patients collected successfully. Using 2 channel-biosensor in NCU is feasible. It also develops a neuromedical database by collecting and monitoring physiological signals to develop future neuromedical research.

Obstructive Sleep Apnea (OSA) has been proven to increase the risk of high blood pressure, heart attack, stroke, obesity, and diabetes. If people would like to know whether they are suffering from this sleep disorder, they need to go to particular hospital with which a sleep center that could perform polysomnography (PSG); however, for most people, this is not convenient. Consequently, the goal of this study is to develop a convenient, lower priced, and easy-to-use home-based sleep monitoring system. The researchers have developed the "Sleep Healthcare Management System" for OSA patients and healthcare providers. It combines smartphone and wearable devices that can perform real-time sleep monitoring. Healthcare providers could apply their professional knowledge to provide customized feedback via a web application. When the patient is diagnosed with an abnormal sleep health condition, healthcare providers may be able to provide appropriate and timely care.

To explore whether depth of sleep is related to changes in autonomic control, continuous power-spectral analysis of the electroencephalogram (EEG) and heart rate variability (HRV) was performed in ten normal subjects during nocturnal sleep. Quiet sleep (QS) was associated with an increase in high-frequency power (HF) of HRV (0.15-0.4 Hz) but a decrease in low-frequency power (LF) (0.04-0.15 Hz) to HF ratio (LF/HF) compared with awakening. During QS, LF/HF was significantly and negatively correlated with delta power of EEG (0.5-4.0 Hz), whereas mean R-R interval and HF were not. We conclude that during QS, cardiac sympathetic regulation is negatively related to the depth of sleep, although vagal regulation is not. Our methodology offers a quantitative analysis to study the interaction between cerebral cortical and autonomic functions.

BACKGROUND: Season of birth (SOB) has been found to be related to cardiovascular mortality, but the mechanisms are unclear. It is suggested that birth in winter is a protective factor for the circulatory system, and this should be able to be observed using heart rate variability (HRV) measurements. The phenomenon may have a sex difference and is likely to be modulated by climatic factors. This study focused on this problem and investigates healthy school‐age children to minimize confounding factors. HYPOTHESIS: Birth in winter is protective to cardiovascular system via autonomic modulation. There is a gender difference in the relationship between SOB and autonomic activity. Climatic factors are the cause of SOB effects on autonomic system. METHODS: A total of 381 healthy school‐age children were recruited for this study. Their HRV profiles were measured once and climatic information related to their month of birth was gathered. The HRV profiles of the 2 sexes and 4 seasons of birth were compared. Correlation and regression analysis were performed to clarify the relationship between climatic factors and the HRV results. RESULTS: Boys born in winter have higher high‐frequency power (HF) but a lower ratio of low‐frequency power to high‐frequency power (LF/HF) than do males born in other seasons. This result is not found for girls. Age and the temperature of the SOB are predictive factors for HF among boys. The humidity of SOB is a predictive factor for normalized low‐frequency power (LF%) and LF/HF among girls. CONCLUSIONS: Season of birth is related to both parasympathetic and sympathetic activity among school‐age children, especially boys. Temperature and humidity are potential causes of this SOB phenomenon.

Fourteen self-reported insomniacs (SRI) and 14 good sleepers (GS) had their cardiac neuronal activity assessed by heart rate variability (HRV) under controlled respiration at a slow frequency rate of 0.1 Hz, and a forced rate of 0.2 Hz during daytime rest. Nighttime sleep was measured by polysomnography. The SRI showed depressed high frequency power of HRV compared to the GS. An increased total power of HRV was observed among the SRI during slow, paced breathing compared with spontaneous breathing and 0.2 Hz. Sleep onset latency, number of awakenings, and awakening time during sleep were decreased and sleep efficiency was increased if SRI practiced slow, paced breathing exercises for 20 min before going to sleep. Our results indicate that there is autonomic dysfunction among insomniacs, especially in relation to vagal activity; however, this decreased vagal activity can be facilitated by practicing slow, paced breathing, thereby improving sleep quality.

Decreased heart rate variability (HRV) has been proposed in bipolar disorder. To date, there has been no adequate study that has investigated resting HRV in unmedicated patients with bipolar disorder in the manic state.To examine whether bipolar mania is associated with decreased HRV, 61 unmedicated patients with bipolar mania and 183 healthy volunteers aged 20-65 years were recruited for this case-control analysis. The Young Mania Rating Scale (YMRS), Clinical Global Impression-Severity, Hamilton Depression Rating Scale (HAM-D), and Hamilton Anxiety Rating Scale (HAM-A) were used for the clinical ratings. Cardiac autonomic function was evaluated by measuring HRV parameters and the frequency-domain indices of HRV were obtained.Patients with bipolar mania exhibited significantly lower mean RR interval, variance, low-frequency (LF)-HRV, and high-frequency (HF)-HRV but higher LF/HF compared to controls. Decreased HRV (variance) was associated with the YMRS total scores. Both the YMRS total scores and the Clinical Global Impression-Severity scores were positively correlated with the LH/HF ratio and inversely correlated with the HF-HRV. There was no significant correlation between the HAM-D/HAM-A scores and any HRV parameter.Bipolar mania is associated with cardiac autonomic dysregulation, highlighting the importance of assessing HRV in manic patients. Further studies examining the influence of anti-manic psychotropic drugs on cardiac autonomic regulation in bipolar mania are needed.

Medical internship is known to be a time of high stress and long working hours, which increases the risk of depression and cardiovascular disease. Gender differences in medical interns' cardiovascular risk have not been reported previously. Thirty-eight medical interns (29 males) were repeatedly tested for depressive symptoms using the Hospital Anxiety and Depression Scale and 5-min spectral analysis of heart rate variability (HRV) at 3-month intervals during their internship. Among the male interns, the variance of the heart rate decreased at 6, 9, 12 months, and a reduced high frequency, which suggests reduced cardiac parasympathetic modulation, was found at 9 and 12 months into their internship. Increased depressive symptoms were also identified at 12 months in the male group. No significant differences in depression or any of the HRV indices were identified among the female interns during their internship.

Repetitive transcranial magnetic stimulation (rTMS) has been reported to be an effective treatment for auditory hallucination (AH) in schizophrenia patients. The efficacy of rTMS and immediate changes in cardiac autonomic function (CAF) after rTMS in severe schizophrenia patients with AH (n = 8) were investigated. Three patients reported aor=50% reduction of AH after rTMS. The ratio of low-frequency power to high-frequency power, an index of sympathetic modulation, increased significantly after rTMS. Further replication studies with larger sample sizes are indicated.

Forearm cutaneous perfusion is an established in vivo model in many clinical and basic researches to explore the peripheral circulation. The aim of our study is to characterize the dynamic properties of regional microcirculation after simultaneous denervation and revascularization in free forearm flap transplantations. Serial changes in laser Doppler flow and cutaneous temperature were measured during 14 forearm flap transplantations. Digitalized perfusion data were relayed for power spectral analysis based on the fast Fourier transform. Real time heart rate variability was measured to verify the influence of systemic autonomic nervous modulations. The basal flow expressed a threefold to fourfold increase, from 20.31 +/- 3.25 to 73.79 +/- 11.78 PU, after the transplantation. Frequency domain analysis of cutaneous blood flow variability showed significantly increased high frequency (0.15-0.4 Hz, 55.14% +/- 3.31% to 65.31% +/- 2.78%, P = 0.0035) and decreased very low frequency (0.003-0.04 Hz, 18.61% +/- 2.70% to 9.25% +/- 1.38%, P = 0.0049) power fraction after flap transfer. Simultaneous denervation and revascularization of forearm flaps increased the regional blood flow significantly that was caused by increased high frequency and decreased very low frequency fractional contributions in dynamic regulation of regional cutaneous microcirculation. They are associated with the sympathetic denervation and reactive hyperemia, respectively.

Several studies have reported that the experience may induce emotional reactions before and after surgery. Various Studies have demonstrated that effective pre-operative information reduces stress and anxiety levels. However, little is known about the effect of pre-operative instruction on autonomic responses as measured by heart rate variability (HRV) before cardiac surgery. Ninety-one patients were randomly assigned to video-tape viewing and teaching booklet group. Electrocardiogram was monitored before and after pre-operative instruction. HRV was analyzed with spectral analysis of frequency domains of heart rate and categorized into low and high frequency (LF and HF). After pre-operative instruction, subjects completed a score of perceived stress and helpfulness. In this study, we found that pre-operative instruction with video-tape was similarly effective as teaching booklets on patients' perceived stress, perceived helpfulness and recovery outcomes. The decrease in HF% and increase in LF/HF ratio of HRV indicate a change in sympathovagal balance toward a lower parasympathetic activity after pre-operative instruction in subjects of both groups. However, the perceived helpfulness of pre-operative instruction may often be associated with a relatively less sympathetic activity. Further studies are needed to determine the optimal timing to enhance the positive effects on the sympathovagal balance after pre-operative instruction.

Autonomic dysfunction and sleep disturbances have been observed in patients with reflux disease. The study aim was to investigate whether acid suppression changed autonomic function and subjective sleep function in patients with erosive esophagitis.Twenty-eight patients with erosive esophagitis underwent assessment of heart rate variability and a subjective sleep questionnaire. All patients were studied before and after esomeprazole or placebo.Esomeprazole resulted in a significant improvement in the reflux symptoms in week 8 (P0.001). The global Pittsburgh Sleep Quality Index score decreased from 6.0 at baseline to 3.6 in week 8 in patients treated with esomeprazole (P0.01). There was no significant change in any variable of heart rate variability in week 8 in either the esomeprazole or the placebo group.In 8 weeks, acid suppression therapy leads to an improvement in sleep disturbances but does not affect autonomic function. The study confirms the utility of acid suppression therapy for the resolution of not only reflux symptoms but also sleep dysfunction.

The study aimed to investigate whether acid suppression influences gastric myoelectrical activity in patients with reflux disease.Twenty-eight patients with erosive esophagitis underwent electrogastrography. All patients were studied before and after esomeprazole. Subjects were divided into mild or moderate esophagitis in order to determine any variation in response related to esophagitis severity.The reflux symptom improved from 4.2 at baseline to 1.0 at week 8 (P0.001). A significant increase in postprandial gastric 3 cycle per minute (normal) activity was observed at week 8 (P0.05). There was also significantly increased postprandial gastric 3 cycle per minute (normal) activity in moderate esophagitis (P0.05).The effect of acid suppression on gastric myoelectrical activity is subtle with an enhancement in normal gastric myoelectrical activity. The myoelectrical response to acid suppression appears to be associated with esophagitis severity.

This study was designed to test the hypothesis that alteration of cardiovascular autonomic functions by vegetarian diets in healthy postmenopausal women is related to lipid metabolism. A total of 70 healthy postmenopausal women not on hormone therapy participated in this study: 35 were vegetarians (mean age 55.0 years) and 35 were omnivores (mean age 55.1 years). Cardiovascular autonomic functions and baroreflex sensitivity were evaluated by specific frequency-domain measures of heart rate variability (HRV) and arterial blood pressure fluctuation. The vegetarians had statistically significant lowered blood pressure, total cholesterol, low-density lipoprotein (LDL) cholesterol, triglyceride, and fasting glucose levels compared with the omnivores. The vegetarians exhibited a significant higher total power, low-frequency (LF; 0.04-0.15 Hz) and high-frequency (HF; 0.15-0.4 Hz) of HRV and increased baroreflex sensitivity measures [Brr(LF) and Brr(HF)] compared with the omnivores. Total power, LF and HF of HRV, Brr(LF), and Brr(HF) were significantly and negatively correlated with LDL-cholesterol concentrations (P0.01). We concluded that the increases of cardiac vagal activity and baroreflex sensitivity by vegetarian diets in postmenopausal women are inversely related to LDL-cholesterol levels.

We aimed to investigate difference in the effects of water and a liquid nutritional meal on the parasympathetic and gastric myoelectrical activities. The study was a repeated-measures design in which each subject was presented with 500 ml of water and a liquid nutritional meal (Ensure) on two separate and random sessions. The electrogastrography (EGG) and electrocardiogram were simultaneously recorded in 16 healthy subjects. There were no significant changes in the EGG-3 cycle per minute (cpm) power, any HRV variable, or the transfer function magnitude after Ensure intake. Water ingestion resulted in a significant increase in both the EGG-3 cpm power and the transfer magnitude compared to Ensure intake (P0.05). The effects of water and Ensure on the parasympathetic and gastric electric activities are different, in which the latter is less likely to provoke an autonomic response after gastric stimulation.

Hypernasality is associated with various diseases and interferes with speech intelligibility. A recently developed quantitative index called voice low tone to high tone ratio (VLHR) was used to estimate nasalization. The voice spectrum is divided into low-frequency power (LFP) and high-frequency power (HFP) by a specific cutoff frequency (600 Hz). VLHR is defined as the division of LFP into HFP and is expressed in decibels. Voice signals of the sustained vowel [a :] and its nasalization in eight subjects with hypernasality were collected for analysis of nasalance and VLHR. The correlation of VLHR with nasalance scores was significant (r = 0.76, p0.01), and so was the correlation between VLHR and perceptual hypernasality scores (r = 0.80, p0.01). Simultaneous recordings of nasal airflow temperature with a thermistor and voice signals in another 8 healthy subjects showed a significant correlation between temperature rate of nasal airflow and VLHR (r = 0.76, p0.01), as well. We conclude that VLHR may become a potential quantitative index of hypernasal speech and can be applied in either basic or clinical studies.

Schizophrenia is a severe mental disorder that requires lifelong treatment, and therefore information on the cardiovascular safety and tolerance of antipsychotics is of significant clinical importance. Atypical antipsychotics have been used to treat schizophrenia patients since the 1990s, and more and more patients have been switched to these from typical antipsychotics; however, there is still no accessible evaluation tool for assessing cardiovascular safety. In this study, we used a computer-assisted 5-min measurement of resting heart rate variability (HRV) in schizophrenia patients who were switched to atypical antipsychotic agents (amisulpride and olanzapine) due to severe side effects (tardive dyskinesia). In 15 patients who switched to amisulpride and 18 to olanzapine, HRV was evaluated before the medication was switched, and patients were followed up every month for 3 months after the switch. Frequency-domain analyses of short-term and stationary respiratory rate (RR) intervals were performed to evaluate low-frequency power (LF; 0.04-0.15 Hz), high-frequency power (HF; 0.15-0.40 Hz), the ratio of LF to HF (LF/HF), and LF in normalized units (LF%). Our results showed significant increases in the mean, variance and HF of RR intervals in the amisulpride group, but not in the olanzapine group. These results indicate that amisulpride has a more vagotonic effect, suggesting greater cardiovascular safety as compared with olanzapine when subjects are switched from typical antipsychotic agents.

There are several methodology based on voice analysis to evaluate nasal airway. Here we introduce a new quantitative index based on voice spectrum analysis to evaluate nasal obstruction. Ten subjects of nasal blockage were instructed to produced the sustained consonant-vowel syllable /m partial partial differential/ at comfortable levels of speech for at least 5 seconds. After nasal decongestant treatment, the second voice sample was collected. Sound spectrum was obtained by the algorithm of fast Fourier transform and the fundamental frequency (F0) was calculated by the method of autocorrelation. Voice low tone to high tone ratio (VLHR) was defined as the division of low frequency power (LFP) into high frequency power (HFP) of the sound power spectrum and was finally expressed in decibels. The cut-off frequency was the product of F0 and square root of (4 x 5). The VLHR after nasal decongestant treatment increased significantly as compared with that before treatment (P0.01). VLHR is a new index derived from sound spectral analysis and that may detect the changes in frequency characteristics of voice during treatment for nasal obstruction. The index is quantitative, non-invasive, and potentially useful for basic researches and clinical applications.

Regulation of cerebral blood flow during orthostatic stress has been a major research topic in patients with orthostatic intolerance such as autonomic dysfunction. Spontaneous fluctuations of middle cerebral artery blood flow velocity (MCAFV) recorded with transcranial Doppler (TCD) have been found to contain information related to cerebrovascular regulation, which can be deciphered with spectral analysis. The purpose of this study was to evaluate the differences in cerebrovascular regulation between healthy volunteers and patients with autonomic dysfunction and orthostatic dizziness for using spectral analysis of MCAFV information derived from TCD during supine rest and orthostasis.Thirteen patients with autonomic dysfunction and orthostatic dizziness were found to have impaired cerebral autoregulation because of failure to maintain adequate cerebral blood flow velocity during a 30-minute head-up tilt study with concomitant TCD and cuff sphygomanometer monitoring. The data of bilateral MCAFV were compared between these 13 patients and 9 healthy volunteers using spectral analysis.Spectral analysis of the MCAFV showed significantly decreased low frequency (LF) power in supine position in the patient group (p = 0.0002). In addition, the spectral power in the very low and low frequency (VLFLF) ranges remained significantly lower in the patient group after tilting up (p0.05).(1). Our study results further support the previous findings that the LF component of the spontaneous fluctuations of MCAFV is important for cerebrovascular regulation. (2) The decreased LF MCAFV power may be a useful indicator or marker of impaired cerebrovascular regulation in patients with autonomic dysfunction.