Creatine supplementation protects spatial memory and long-term potentiation against chronic restraint stress.

Stress contributes to numerous psychopathologies, including memory impairment, and threatens one's well-being. It has been reported that creatine supplementation potentially influences cognitive processing. Hence, in this study, we examined the effects of creatine supplementation on memory, synaptic plasticity, and neuronal arborization in the CA1 region of the hippocampus in rats under chronic restraint stress (CRS). Thirty-two adult male Wistar rats (8 weeks old) weighing 200-250 g were randomly divided into four groups (n = 8/per group): control, stress, creatine, and stress + creatine. CRS was induced for 6 h per day for 14 days, and creatine supplementation was carried out by dissolving creatine (2 g/kg body weight per day) in the animals' drinking water for 14 days. We used the Barnes maze and shuttle box for spatial and passive avoidance memory examination. The in-vivo field potential recording and Golgi-Cox staining were also used to investigate long-term potentiation (LTP) and dendrite arborization in the CA1 pyramidal neurons. Chronic stress impaired spatial memory, dysregulated LTP parameters, and decreased the number of dendrites in the CA1 pyramidal neurons of stressed rats, and creatine supplementation modified these effects in stressed rats. It seems that creatine supplementation can improve spatial memory deficits and synaptic plasticity loss induced by CRS in hippocampal CA1 neurons, possibly by reducing the dendrite arborization damages. However, understanding its mechanism needs further investigation.

The Complexity of Electroencephalographic Signal Decreases during the Social Stress.

Social stress affects brain function. Trier social stress test (TSST) is a standard test to assess it. The study aimed to analyze the electroencephalographic (EEG) recording during and after TSST in healthy subjects. The EEG signals of 44 healthy men participating in the study were recorded in the control condition, during and after TSST and after 30 min of recovery. Salivary cortisol (SC) and the Emotional Visual Analog Scale (EVAS) score were measured in the control condition, after TSST, and after the recovery period. The false discovery rate correction was used to control the false positive of significance in EEG. In the comparison control condition, the SC and EVAS levels significantly increased after TSST. The relative Delta band frequency significantly increased during TSST. On the other hand, the Beta bands and, in less amount, the Theta and Gamma 1 (30-40 Hz) oscillations decreased, especially in the frontal region. The nonlinear features such as, approximate and spectral entropy, Katz fractal dimension behaved like Beta band oscillation. All changes returned to baseline after TSST except the increase of Katz in the F3 channel after the recovery period. Thus, stress on EEG increased low frequency (1-4 Hz), decreased high frequency (13-40 Hz), and complexity indices during TSST.

Changes in psychological and cognitive variables as well as cortisol levels in recovered Covid-19 patients: a longitudinal study.

BACKGROUND: Decreased psychological and cognitive functioning is one of the complications of Covid-19 disease. We aimed to evaluate mental health, cognitive functioning, and salivary cortisol levels in Covid-19 patients with different disease severities in three 45-day intervals after recovery. METHODS: 258 Covid-19 patients were assigned into three groups based on their disease severity: 112 patients in mild group, 67 patients in moderate group and 79 patients in severe group. The participants underwent psychological evaluations (including Depression, Anxiety and Stress Scale questionnaire, Beck Depression Inventory, SpeilBerger State-Trait Anxiety Inventory, Pittsburgh Sleep Quality Inventory), cognitive assessments (The Paced Auditory Serial Addition Test) and salivary cortisol level evaluation in three 45-day periods. Non-parametric statistical methods were applied for psychological and cognitive indicators, while two-way mixed model ANOVA was used to evaluate the cortisol concentration in three replications. RESULTS: The group of mild patients became more anxious and the group of moderate patients became more anxious and depressed. But all three groups of patients developed severe sleep disorders over time. For cognitive functioning, although the results showed a decrease in the correct response rate, a significant increase in the correct response rate was observed in all three groups in all three measurements. However, the response speed not only did not increase, but also decreased in severe group. Cortisol level had a markedly increasing trend in all three groups. CONCLUSION: Improvement of cognitive functioning was in line with the increase in cortisol. Besides, the decrease in mental health had no effect on the cognitive functioning.

Impact of the covid-19 pandemic on the psychological status and cortisol level of multiple sclerosis patients.

This study aimed to compare the changes in psychological status and cortisol level between multiple sclerosis (MS) patients and a healthy control group (HC). One hundred and fifty-five MS patients and 165 HC subjects had completed questionnaires consisting of 36-Item short health survey (SF-36), Hamilton Anxiety Rating Scale (HAM-A), Beck Depression Inventory-II (BDI-II), and fatigue severity score (FSS) before and after (one year from onset) COVID-19 pandemic. The salivary cortisol level was also measured again in 26 MS patients and 14 control individuals. MS patients had lower scores of mental and physical components of quality of life (MCS and PCS), but higher HAM-A, FSS, and BDII scores than HC Before and after COVID-19. There were significant changes in scores of MCS, BDI-II, HAM-A, and FSS after the COVID-19 outbreak in MS patients, but not in PCS score. In HC group, we observed significant changes in scores of MCS, BDI-II, and FSS, but not in scores of PCS and HAM-A. Compared to HC, the MS patients reported greater deterioration in the overall mental health component of their health-related quality of life, and their levels of anxiety and fatigue over the study period. The change of cortisol levels was non-significant with a small effect size.

Adrenal histological and functional changes after hepatic encephalopathy: From mice model to an integrative bioinformatics analysis.

Hepatic encephalopathy (HE), which is caused by neurotoxin agents in the liver, is a complicated condition with a variety of neurological manifestations. Recently, endocrine alterations have been more paid attention to for neurological severity in the course of HE, e.g. adrenal gland. To identify the role of adrenal gland in the context of HE, we evaluated the functional changes of adrenal gland (i.e., plasma corticosterone concentrations and histopathological changes) in mice model of HE. To dig deep into the molecular and genetic underpinnings, a comprehensive enrichment analysis for shared genes between HE and adrenal insufficiency (AI) was also performed. Our results showed a significant reduction in the level of plasma corticosterone and severe cellular necrosis in zona fasciculate of adrenal cortex, possibly indicating adrenal insufficiency. Enrichment analysis indicated four common genes, besides predicted five novel genes and some significant MicroRNAs (miRNAs) and transcription factors for both HE and AI. Couples with, several biological processes, such as DNA damage, inflammatory responses, glycolytic processes, and insulin receptor signaling pathway were predicted in both HE and AI. To sum up, data from experimental tests and bioinformatics analyses suggest that AI play an important role in the pathogenesis and progression of HE.

Islamic praying changes stress-related hormones and genes.

Islamic praying (Namaz) can be considered a mental, spiritual, and physical practice. The study aimed to investigate the early effect of Namaz on stress-related hormones and the expression of stress-induced genes such as IL6 and BDNF. Eighty-three healthy women and men who continually practice Namaz participated in the study. The saliva samples were taken before and after Namaz to measure cortisol and alpha-amylase hormone levels. Also, to evaluate the expression of BDNF and IL6 genes, 11 specimens were selected randomly. Based on baseline sampling, the participants were classified into three groups: cortisol levels lower than 5, between 5-15, and upper than 15 ng/ml. The results indicated that cortisol significantly increased and decreased in the first and third groups after Namaz, respectively. In addition, the increase of alpha-amylase also occurred in subjects with a low baseline level of its concentration. Regarding genetic expression examination, there was a significant decrease in BDNF gene expression after the Namaz. In addition, the change of cortisol and alpha-amylase hormones after Namaz related to the baseline level changed to approach the optimal range after Namaz. These findings were reported for the first time and need more studies.

The Relationship between the Severity of the COVID-19 Disease, Temperament and Psychological Factors.

Objective: The coronavirus (COVID-19) pandemic negatively affects public mental health around the world. Individuals' reactions to COVID-19 vary depending on their temperament, individual differences, and personality traits. Therefore, the current study is conducted to assess the association of demographical features, Persian temperament, and psychological characteristics with the severity of COVID-19. Method: An online survey was sent to COVID-19 patients to collect their demographic information, COVID-19 symptoms, and clinical data. The Depression, Anxiety and Stress Scale (DAAS-21) questionnaire, Beck Depression Inventory (BDI-II), Spiel Berger State-Trait Anxiety Inventory (STAI) , Pittsburgh Sleep Quality Inventory (PSQI), and Persian general and brain temperament Questionnaire were also completed by 258 participants (127 men and 131 women) 45 days after recovery from COVID-19. Non-parametric analysis was used for statistical analysis. Results: Results showed the significant relationship of demographic factors such as weight, age and gender with the severity of the COVID-19 (P < 0.05). Mean scores of brain temperament (warm/cold) in the severe group were significantly lower than the moderate and mild groups (P < 0.05). There was a significant increase in the dry/wet temperament of the brain in the severe and moderate groups compared to the mild group (P < 0.05). The results of DASS-21 showed a significantly higher anxiety in patients with severe COVID-19 compared with moderate and mild groups (P < 0.05). The severe group was found to be significantly different compared to moderate group in the results of BDI-II (P < 0.05). The result of STAI (state and trait) showed a significant difference between the severe group and the mild and moderate groups. The score of PSQI between the moderate and mild groups was significant (P < 0.05). Conclusion: These results indicate the relationship between demographic factors such as weight, age and gender, brain temperament, as well as some psychological factors such as sleep quality and anxiety with the severity of the COVID-19 disease.

Prediction of salivary cortisol level by electroencephalography features.

Change in cortisol affects brain EEG signals. So, the identification of the significant EEG features which are sensitized to cortisol concentration was the aim of the present study. From 468 participated healthy subjects, the salivary samples were taken to test the cortisol concentration and EEG signal recording was done simultaneously. Then, the subjects were categorized into three classes based on the salivary cortisol concentration (<5, 5-15 and >15 nmol/l). Some linear and nonlinear features extracted and finally, in order to investigate the relationship between cortisol level and EEG features, the following steps were taken on features in sequence: Genetic Algorithm, Neighboring Component Analysis, polyfit, artificial neural network and support vector machine classification. Two classifications were considered as following: state 1 categorized the subjects into three groups (three classes) and the second state put them into two groups (group 1: class 1 and 3, group 2: class 2). The best classification was done using ANN in the second state with the accuracy=94.1% while it was 92.7% in the first state. EEG features carefully predicted the cortisol level. This result is applicable to design the intelligence brain computer machines to control stress and brain performance.

Crocin attenuates the granular cells damages on the dentate gyrus and pyramidal neurons in the CA3 regions of the hippocampus and frontal cortex in the rat model of Alzheimer's disease.

Amyloid ß-peptides (Aß) are considered as a major hallmark of Alzheimer's disease (AD) that can induce synaptic loss and apoptosis in brain regions, particularly in the cortex and the hippocampus. Evidence suggests that crocin, as the major component of saffron, can exhibit neuromodulatory effects in AD. However, specific data related to their efficacy to attenuate the synaptic loss and neuronal death in animal models of AD are limited. Hence, we investigated the efficacy of crocin in the CA3 and dentate gyrus (DG) regions of the hippocampus and also in frontal cortex neurons employing a rat model of AD. Male Wistar rats were randomly divided into control, sham, AD model, crocin, and AD model + crocin groups, with 8 rats per group. AD model was established by injecting Aß1-42 into the frontal cortex rats, and thereafter the rats were administrated by crocin (30 mg/kg) for a duration of 12-day. The number of live cells, neuronal arborization and apoptosis were measured using a Cresyl violet, Golgi-Cox and TUNEL staining, respectively. Results showed that, the number of live cells in the hippocampus pyramidal neurons in the CA3 and granular cells in the DG regions of the AD rats significantly decreased, which was significantly rescued by crocin. Compared with the control group, the axonal, spine and dendrites arborization in the frontal cortex and CA3 region of the AD model group significantly decreased. The crocin could significantly reverse this arborization loss in the AD rats (P < 0.05). The apoptotic cell number in the CA3 and DG regions in the AD model group was significantly higher than that of the control group (P < 0.05), while crocin significantly decreased the apoptotic cell number in the AD group (P < 0.05). Conclusion. Crocin can improve the synaptic loss and neuronal death of the AD rats possibly by reducing the neuronal apoptosis.

The controlling role of nitric oxide within the shell of nucleus accumbens in the stress-induced metabolic disturbance.

CONTEXT AND OBJECTIVES: The involvement of the nitricergic system within the shell part of the nucleus accumbens (NAc) was evaluated in the metabolic disturbances due to stress. MATERIALS AND METHODS: Male Wistar rats were cannulated in the shell of the left NAc. They received either saline or different doses of L-arginine and/or L-NAME five minutes before each stress session, for four days. Plasma cortisol concentration, food and water intake, time elapsing for eating, animal weight changes and adrenal gland weight were recorded. RESULTS: The L-arginine 1 µg/rat decreased the level of cortisol, water and food intake and time of feeding and increased the adrenal weight. But L-NAME at 1 µg/rat had opposite effects on these factors. However, the drugs showed similar effects at 10 µg/rat. CONCLUSION: Injection of nitric oxide modifiers into the left side of NAc shell part may have an interactive role with sub-chronic stress in metabolic behaviour.

Assessment of mental health, knowledge, and attitude of patients with multiple sclerosis and neuromyelitis optica spectrum disorder in response to 2019 novel coronavirus.

BACKGROUND: With the recent pandemic of the novel coronavirus disease (COVID-19), multiple sclerosis (MS) and neuromyelitis optica spectrum disorder (NMOSD) patients for their compromised immune system have been in significant concern. Awareness and attitude about this virus have an important impact on infection prevention and coping with stress and anxiety. So we conducted this study to assess knowledge, attitude, and mental health status in MS and NMOSD patients within the COVID-19 pandemic. METHOD: In this cross-sectional study, the link of Depression Anxiety Stress Scales-21 (DASS-21) and a self-administered structured questionnaire were sent through social media to MS and NMOSD patients and two control groups consisting of healthy and migraine individuals. RESULTS: A total of 223 MS patients, 41 NMOSD, 29 migraine, and 245 healthy subjects participated in this study. MS patients had higher total DASS scores compared to healthy participants (p = 0.012). There were no significant differences among the study groups regarding knowledge and attitude. In MS patients, physical comorbidity was associated with a total score of attitude (OR 1.59, 95% CI 0.53, 2.66, p = 0.004). We did not find association between other demographic and clinical variables with DASS scores, attitude, and knowledge in MS patients. CONCLUSION: The current data highlight the necessity of attitude, knowledge, and mental health assessment among MS and NMOSD patients. Further studies in other countries need to be carried to assess these points among MS and NMOSD patients.

The persistent effect of acute psychosocial stress on heart rate variability.

BACKGROUND: As stress occurs repetitively every day, the biological modifiers should also have enough time to restore the normal state of hemostasis; otherwise, chronic stress would be anticipated. The aim of the present study was to examine the persistence of stress based on subjective emotion, salivary cortisol, and linear and non-linear features of heart rate variability (HRV) in both genders. METHODS: Thirty-three healthy young volunteers (23 men and 10 women) participating in this study were exposed to the Trier Social Stress Test (TSST). Moreover, the emotional visual analog scale (EVAS), salivary cortisol, and ECG recording in the rest state were taken before and after TSST as well as 20 min after recovery. RESULTS: According to the results of the two-way mixed model ANOVA, all volunteers showed a significant increase in EVAS after TSST which was restored to the baseline state after recovery. Notably, the women's base of cortisol was significantly higher than men and the standard range of kit. Cortisol elevation was only observed in the men, and the significant increase of LF/HF ratio was observed in the women, while both did not retain to the baseline after recovery. The SD1 of Poincaré plot and spectral entropy decreased after stress in both genders. Moreover, there was a significant negative correlation between baseline level of cortisol and its elevation due to stress and some features of HRV. CONCLUSION: The base of cortisol played a critical role in modifying the physiological response to stress. In addition, after recovery, no stressful emotion remained, while the non-linear features of HRV did not return to baseline.

The Effect of Prostration (Sajdah) on the Prefrontal Brain Activity: A Pilot Study.

INTRODUCTION: "Sajdah", a prostration position, is part of Muslim daily prayers. It seems to have several effects on the brain and heart function. This study aimed to investigate the prefrontal brain activity after 10 seconds of Sajdah in the direction of Qibla (the direction that a Muslim prays) while putting the forehead on the ground. METHODS: Three women and two men participated in this pilot study. Linear (absolute and relative power of θ (4-8Hz), α 1 (8-10 Hz), α 2 (10-12 Hz), ß 1 (12-16 Hz), ß 2 (16-20 Hz), ß 3 (20-30 Hz), γ 1 (30-40 Hz), γ 2 (40-50 Hz) and non-linear features (approximate entropy, Katz fractal dimension, Petrosian fractal dimension, spectral entropy, and sample entropy) from Fps channel were calculated. RESULTS: The relative ß to γ band, approximate and sample entropy, Petrosian fractal dimension and mean of amplitude decreased in open eye state in women. While θ to γ bands in the closed eye state decreased after Sajdah in women. The absolute γ bands in closed eye state and relative ß band in open eye state increased after Sajdah in men. CONCLUSION: The pilot study showed that 10 seconds of Sajdah has effects on brain activity and sometimes showed the opposite effect on genders.

Saffron (Crocus sativus) aqueous extract reverses the hypothalamus-pituitary-adrenal axis activity in rat model of post-traumatic stress disorder

Abstract Crocus sativus L., Iridaceae, has been used worldwide in traditional medicinefor treatment ofsome neurological disorderssuch as depression. Post-traumatic stress disorder is a mental disorder developed in peoplewho experience stressful events. Since stress has been proposed tocause thehypothalamic-pituitary-adrenal axis malfunction in post-traumatic stress disorder patients, this study aimed at investigating the effect of saffron aqueous extract on hypothalamic-pituitary-adrenal axis activity in rats of post-traumatic stress disorder model. Here, Post-traumatic stress disorder animals received an acute electro foot shock; however, 5 min before the stress session, these animals received an intra-cerebral-ventricular (10 µg/rat) infusion of either saffron aqueous extract or saline. Twenty one days later, they were re-exposedto the stress box withoutinducing stress, andthen were examined for their freezing behavior. The impact of stress and saffron aqueous extract on serum corticosterone, corticotrophin releasing hormone gene expression in hypothalamus and glucocorticoid receptor gene expression in pituitary gland werethen evaluated on day 28. Intra-cerebral-ventricular injection of saffron aqueous extract resulted in an increase in serum corticosterone level and reduced symptoms of freezing behavior, and corticotrophin releasing hormone and glucocorticoid receptor gene expression in post-traumatic stress disorder groups.Saffron administration could improve the symptoms of stress-induced post-traumatic stress disorder, possiblythrough the adjustment ofhypothalamic-pituitary-adrenal axis function.

Spiral waves in externally excited neuronal network: Solvable model with a monotonically differentiable magnetic flux.

Spiral waves are particular spatiotemporal patterns connected to specific phase singularities representing topological wave dislocations or nodes of zero amplitude, witnessed in a wide range of complex systems such as neuronal networks. The appearance of these waves is linked to the network structure as well as the diffusion dynamics of its blocks. We report a novel form of the Hindmarsh-Rose neuron model utilized as a square neuronal network, showing the remarkable multistructure of dynamical patterns ranging from characteristic spiral wave domains of spatiotemporal phase coherence to regions of hyperchaos. The proposed model comprises a hyperbolic memductance function as the monotone differentiable magnetic flux. Hindmarsh-Rose neurons with an external electromagnetic excitation are considered in three different cases: no excitation, periodic excitation, and quasiperiodic excitation. We performed an extensive study of the neuronal dynamics including calculation of equilibrium points, bifurcation analysis, and Lyapunov spectrum. We have found the property of antimonotonicity in bifurcation scenarios with no excitation or periodic excitation and identified wide regions of hyperchaos in the case of quasiperiodic excitation. Furthermore, the formation and elimination of the spiral waves in each case of external excitation with respect to stimuli parameters are investigated. We have identified novel forms of Hindmarsh-Rose bursting dynamics. Our findings reveal multipartite spiral wave formations and symmetry breaking spatiotemporal dynamics of the neuronal model that may find broad practical applications.

Force Variability in the Short- and Long-Term Type 2 Diabetes Mellitus.

BACKGROUND: Force variability is related to many kinesiological and neuromuscular properties of the body. This study was conducted to evaluate the effect of type 2 diabetes mellitus (T2DM) and sex on the several fractal and entropy indices of force changing during the repetitive isokinetic exercise of knee flexion-extension. METHODS: Fifty individuals were allowed to participate in the study, and they consist of 18 patients with short-term T2DM, 12 patients with long-term T2DM, and 20 gender/body mass index/ankle imposed to brachial pressure index and physical activity index-matched healthy control (HC) individuals. Torque of knee flexion-extension was recorded for each cycle of 40 isokinetic repetitions at a velocity of 150°/s. The slope across the peak of torques and nonlinear fractal and entropy features in the time series was calculated. Two-way univariate analysis of variance was used to analyze the effect of the groups and gender on the variables. RESULTS: The slope of flexor peak torques was significantly less in the long-term T2DM than the other groups. However, the fractal features such as SD1 and 2 of Poincare plot and fractal dimension katz were significantly decreased in the T2DM groups than the HC and in the women than men. Alpha detrended fluctuation analysis and empirical hurts exponent increased in women of short-term T2DM than men. CONCLUSION: The force variability decreased in the T2DM as compared to HC and in women as compared to men. However, the randomness of force was significantly increased in women of short-term T2DM.

Protective properties of the aqueous extract of saffron (Crocus sativus L.) in ischemic stroke, randomized clinical trial.

ETHNOPHARMACOLOGICAL RELEVANCE: Crocus sativus L. has been used throughout the world in traditional medicine as a treatment for neurological disorders such as depression. Growing attention is currently being paid to the use of neuroprotective agents in ischemic strokes. AIM OF THE STUDY: This study assed the effect of saffron as a neuroprotective natural product in cerebral ischemia in human. STUDY DESIGN: Patients with acute ischemic stroke were randomly allocated to receive either routine stroke care (control group, n = 20) or routine care plus aqueous extract of saffron capsule (200 mg/day) (saffron-treated group, n = 19). Both groups were monitored during their four-day hospital stay and the three-month follow-up period. The groups were compared in terms of short- and long-term effects of saffron capsules using the National Institute of Health Stoke Scale (NIHSS), Barthel Scale, and serum neuron specific enolase (NSE), Brain-derived neurotrophic factor (BDNF), S100 levels. RESULTS: Based on the NIHSS, the severity of stroke during the first four days was significantly lower in the saffron-treated group than in the control group (P < 0.05). Compared to the levels on the first day, serum NSE and s100 levels were significantly decreased and BDNF concentration was increased in the saffron-treated group on the fourth day. Also, our results showed there was a negative significant non-linear cubic regression between BDNF concentration and score of NIHSS. At the end of the three-month follow-up period, the mean Barthel index was significantly higher in the saffron-treated group than in the control group (P < 0.001). CONCLUSION: The results of this study confirmed the short and long-term neuroprotective effects of aqueous extract of saffron on ischemic stroke in humans.

Ventral tegmental area inactivation alters hormonal, metabolic, and locomotor responses to inescapable stress.

Context: The involvement of unilateral and bilateral inhibition of the ventral tegmental area (VTA) in response to stress is not well understood. Objective: In the present study, the effect of unilateral and bilateral inhibition of the VTA on hormonal, metabolic, and locomotor responses to stress was assessed. Material and methods: Male rats seven days after cannulation into the VTA received electro foot-shock stress for seven consecutive days. Twenty minutes before induction of stress, 2% lidocaine hydrochloride or sterile saline (control) was injected either uni- or bi-laterally into the VTA. Results: Results showed that stress significantly increased serum corticosterone level, adrenal gland weight and anorexia, reduced weight gain, food-intake, and locomotor activity. However, bilateral inactivation of VTA prevented stress-induced these parameters changes. Conclusion: The present study demonstrated that the bilateral VTA blockade effectively relieves the symptoms of stress, while the unilateral VTA blockade does not significantly improve the changes caused by stress.

The Psychophysiological Responses of the Chronic Ischemic Stroke Patients to the Acute Stress were Changed

Abstract: Mood disorder is one of the complications of stroke. The inability to cope with stress is also a prognosis of depression and anxiety. The aim of this study is to assess the response of stress system in the post stroke patients. Twelve healthy controls (HC) and twelve post-stroke patients after filling in the State-Trait Anxiety Inventory completed the Trier Social Stress Test (TSST) which induces acute stress. Salivary samples were collected to determine salivary cortisol levels and ECG record were taken in four times (before, right after stress, after two recoveries: 20 and 40 minutes after stress). ECG was also recorded during TSST and then the linear and non-linear features of Heart Rate Variability (HRV) were analyzed. The results showed that trait anxiety score and baseline salivary cortisol level were higher in post stroke than HC group (P-value <0.05). The increase of cortisol level after stress was only observed in HC that returned to baseline after the second recovery time. The stress increased the relative low frequency of HRV in both groups, however it was significantly lower in the stroke than HC group (P-value < 0.005). There was also a significant difference between alpha 1 DFA measures in stroke group and HC group (P-value <0.05). It is concluded that the impairment of the hormonal axis of stress system in the post-stroke patients that until now was not reported.

Performance comparison of machine learning techniques in sleep scoring based on wavelet features and neighboring component analysis.

INTRODUCTION: Sleep scoring is an important step in the treatment of sleep disorders. Manual annotation of sleep stages is time-consuming and experience-relevant and, therefore, needs to be done using machine learning techniques. METHODS: Sleep-EDF polysomnography was used in this study as a dataset. Support vector machines and artificial neural network performance were compared in sleep scoring using wavelet tree features and neighborhood component analysis. RESULTS: Neighboring component analysis as a combination of linear and non-linear feature selection method had a substantial role in feature dimension reduction. Artificial neural network and support vector machine achieved 90.30% and 89.93% accuracy, respectively. DISCUSSION AND CONCLUSION: Similar to the state of the art performance, the introduced method in the present study achieved an acceptable performance in sleep scoring. Furthermore, its performance can be enhanced using a technique combined with other techniques in feature generation and dimension reduction. It is hoped that, in the future, intelligent techniques can be used in the process of diagnosing and treating sleep disorders.