Inadequate sleep as a contributor to impaired glucose tolerance: A cross-sectional study in children, adolescents, and young adults with circadian rhythm sleep-wake disorder.

BACKGROUND: Sleep deprivation and circadian disruption are associated with decreased insulin sensitivity and hyperglycemia. It is uncertain whether circadian sleep-wake disorder (CRSWD), which relates to both the homeostatic sleep system and the circadian timing system, affects glycemic regulation and insulin secretion. We aimed to examine the associations among sleep duration, sleep architecture or circadian rhythm of the sleep-wake cycle, and glucose metabolism in children, adolescents, and young adults with CRSWD. METHODS: This cross-sectional observational study of 124 patients with CRSWD took place at Hyogo Children's Sleep and Development Medical Research Center in Hyogo, Japan. The patients underwent a 3-hour oral glucose tolerance test, anthropometric measurements, sleep-log analyses, and polysomnography. Analysis of covariance models were used to assess the association between sleep architecture or circadian rhythm of sleep-wake cycle and glucose/insulin homeostasis, adjusted for confounding variables such as age, gender, standardized body mass index, and sleep apnea index. RESULTS: Impaired glucose tolerance was detected in 25.8% of all patients with CRSWD. After adjustment for confounding variables, we found a negative association between total sleep time (TST) and the 2-hour plasma glucose level. Stage N1 (%TST) was also a significant predictor of 3-hour glucose level. However, we did not detect an association between circadian rhythm of the sleep-wake cycle and glucose/insulin measures. CONCLUSIONS: Decreased sleep duration and increased stage N1 (%TST) were associated with hyperglycemia in patients with CRSWD. Further research should elucidate how circadian misalignment in patients with CRSWD is associated with glucose and insulin homeostasis.

Disruption of Circadian Sleep/Wake Rhythms in Infants May Herald Future Development of Autism Spectrum Disorder.

We investigated whether the abnormal rhythms in infants are related to the future development of autism spectrum disorder (ASD), using a questionnaire from September to October 2016. The parents of 160 children with ASD (male, n = 123; female, n = 37) were recruited from two hospitals in K and H cities, and as a control group, 145 children (male, n = 75; female, n = 70) were recruited from four nursery schools in T city. The associations between ASD and bedtime and waking time on weekdays and weekends in infancy (<1 years of age), at 1-3 years, and at 3-5 years of ages were studied using a multivariable logistic regression analysis. In particular, at <3 years of age, the following factors were associated with an increased prevalence of ASD in the future: (1) short sleep periods (<8 h); (2) taking a long time to fall asleep (>60 min); (3) sleep beginning after 22:00; (4) a wake-up time after 08:00; and (5) frequent (>3 times) and long-term awakening periods (>60 min). The misalignment and/or shift of the circadian rhythm in infants may be one of the precursors and/or risk factors for the future development of ASD.

Autonomic function is associated with health-related quality of life in patients with end-stage renal disease: a case-control study.

OBJECTIVE: In the present study, we assessed the associations among fatigue, quality of life (QOL), clinical parameters, and body mass index (BMI) with autonomic function in end-stage renal disease (ESRD) patients undergoing hemodialysis as well as fatigue-free healthy subjects. DESIGN AND METHODS: This was a case-control study. This study compared autonomic function in ESRD patients (n = 192) to that of healthy subjects (n = 282) and evaluated its association with fatigue, QOL, and clinical parameters such as glucose, albumin, cholesterol, and BMI. Fatigue was evaluated by a recently established fatigue questionnaire and performance status, and QOL was evaluated with the kidney disease QOL questionnaire. With regards to autonomic function, spontaneous beat-to-beat variations were measured, according to time- (standard deviation of all normal a-wave intervals [CVa-a%]) and frequency domains (low frequency [LF] power, high frequency [HF] power, and LF/HF ratio) with acceleration plethysmography. RESULTS: CVa-a%, LF power, HF power, and LF/HF ratio were significantly lower in ESRD patients than healthy subjects. There were significant inverse correlations between these factors and age in healthy subjects, but not in ESRD patients. Although the fatigue score was not associated with any autonomic parameters, ESRD patients with impaired performance status exhibited a significantly lower LF/HF ratio. Moreover, in ESRD patients, the LF/HF ratio was significantly and positively associated with several components of QOL, including physical functioning and role emotional, independent of other clinical parameters and BMI. CONCLUSIONS: Impaired autonomic function is significantly associated with fatigue and impaired QOL in dialysis patients.

Weakened Bayesian Calibration for Tactile Temporal Order Judgment in Individuals with Higher Autistic Traits.

Previous psychophysical studies reported a positive aftereffect in tactile temporal order judgments, which can be explained by the Bayesian estimation model ('Bayesian calibration'). We investigated the relationship between Bayesian calibration and autistic traits in participants with typical development (TD) and autism spectrum disorder (ASD). Bayesian calibration was weakened in TD participants with high autistic traits, consistent with the 'hypo-priors' hypothesis for autistic perceptions. The results from the ASD group were generally observed as a continuation of those from the TD groups. Meanwhile, two ASD participants showed irregularly large positive or negative aftereffects. We discussed the mechanisms behind the general results among TD and ASD participants and two particular results among ASD participants based on the Bayesian estimation model.

Premorbid personality in chronic fatigue syndrome as determined by the Temperament and Character Inventory.

BACKGROUND: Using the Temperament and Character Inventory (TCI), we examined personality characteristics in patients with chronic fatigue syndrome (CFS) compared with healthy control subjects, and CFS patients with and without psychiatric diseases. There have been no previous reports assessing personality in CFS patients using the TCI. METHODS: A total of 211 CFS patients and 90 control subjects completed the TCI and the Chalder Fatigue Scale questionnaires. RESULTS: Compared with control subjects, CFS patients demonstrated significantly lower premorbid Novelty Seeking, and higher Harm Avoidance and persistence. The fatigue score for CFS patients with psychiatric diseases was higher than that for CFS patients without psychiatric diseases. Patients with CFS with psychiatric diseases showed lower premorbid Self-Directedness when compared with CFS patients without psychiatric diseases. The fatigue score was negatively correlated with premorbid Self-Directedness and Cooperativeness, and positively correlated with Harm Avoidance among CFS patients. CONCLUSION: This study supported the stereotyped image of CFS patients as perfectionists, which is similar to the Persistence score, and neurotics, which is similar to the Harm Avoidance score. Patients displaying greater neuroticisms and poorer social and communication skills, similar to the Self-Directedness and Cooperativeness scores, tend to have intercurrent psychiatry diseases and show more severe symptoms of CFS.

Neonatal irritable sleep-wake rhythm as a predictor of autism spectrum disorders.

Recently, it has been suggested that sleep problems in autism spectrum disorder (ASD) not only are associated symptoms, but may be deeply related to ASD pathogenesis. Common clinical practice relating to developmental disorders, has shown that parents of children with ASD have often stated that it is more difficult to raise children in the neonatal period because these children exhibit sleep problems. This study investigated the possibility that abnormal neonatal sleep-wake rhythms are related to future ASD development. We administered questionnaires to assess parent(s) of children with ASD and controls. A retrospective analysis was conducted among 121 children with ASD (94 male and 27 female children) recruited from the K-Development Support Center for Children (K-ASD), 56 children with ASD (40 male and 16 female children) recruited from the H-Children's Sleep and Development Medical Research Center (H-ASD) and 203 children (104 male and 99 female children) recruited from four nursery schools in T-city (control). Irritable/over-reactive types of sleep-wake rhythms that cause difficulty in raising children, such as 1) frequently waking up, 2) difficulty falling asleep, 3) short sleep hours, and 4) continuous crying and grumpiness, were observed more often in ASD groups than in the control group. Additionally, the number of the mothers who went to bed after midnight during pregnancy was higher in the ASD groups than in the control group. Sleep-wake rhythm abnormalities in neonates may be considerable precursors to future development of ASD. Formation of ultradian and postnatal circadian rhythms should be given more attention when considering ASD development. Although this is a retrospective study, the results suggest that a prospective study regarding this issue may be important in understanding and discovering intervention areas that may contribute to preventing and/or properly treating ASD.

Cutaneous and stick rabbit illusions in individuals with autism spectrum disorder.

Prediction is the process by which future events are anticipated based on past events; in contrast, postdiction is the retrospective interpretation of past events based on latter, more recent events. The prediction and postdiction are suggested to be similar based on theoretical models. Previous studies suggest that prediction is impaired in individuals with autism spectrum disorder (ASD). However, it is unclear whether postdiction is also impaired in individuals with ASD. In this study, we evaluated postdiction in individuals with ASD using the cutaneous and stick rabbit illusion paradigms in which the perceived location of a touch shifts postdictively in response to a subsequent touch stimulus. We observed significant cutaneous and stick rabbit illusion in both typically developing (TD) and ASD groups; therefore, postdiction was functional in individuals with ASD. Our present results suggest that postdiction involves a different neuronal process than prediction. We also observed that the ASD group exhibited significantly larger individual difference compared with the TD group in the stick rabbit illusion, which is considered to reflect extension of body schema to external objects. We discuss implications of the individual difference among the ASD participants in the context of sports requiring interactions between the body and external objects.

Central nervous system fatigue alters autonomic nerve activity.

AIMS: Fatigue is a common symptom in modern society. In order to clarify the mechanisms underlying fatigue, we examined the association between central nervous system fatigue and autonomic nerve activity. MAIN METHODS: The study group consisted of 20 healthy subjects. They performed the 2-back test for 30 min to induce fatigue. Just before and after the fatigue-inducing session, they completed the advanced trail making test (ATMT) for 30 min as a fatigue-evaluating task session. In order to measure autonomic nerve activity, electrocardiograms were monitored continuously throughout the experiment. KEY FINDINGS: After the fatigue-inducing task session, impaired task performance was demonstrated based on the total trial number and error counts of the ATMT. During the task session, although task performance as measured using the accuracy and the mean reaction time of the 2-back test was almost unchanged, electrocardiographic R-R wave interval analyses showed a decreased high-frequency component power and an increasing trend in the low-frequency component power/high-frequency component power ratio. SIGNIFICANCE: Decreased vagal nerve activity and increased sympathetic nerve activity are associated with central nervous system fatigue.

Personality traits associated with intrinsic academic motivation in medical students.

OBJECTIVES: Motivation is one of the most important psychological concepts in education and is related to academic outcomes in medical students. In this study, the relationships between personality traits and intrinsic academic motivation were examined in medical students. METHODS: The study group consisted of 119 Year 2 medical students at Osaka City University Graduate School of Medicine. They completed questionnaires dealing with intrinsic academic motivation (the Intrinsic Motivation Scale toward Learning) and personality (the Temperament and Character Inventory [TCI]). RESULTS: On simple regression analyses, the TCI dimensions of persistence, self-directedness, co-operativeness and self-transcendence were positively associated with intrinsic academic motivation. On multiple regression analysis adjusted for age and gender, the TCI dimensions of persistence, self-directedness and self-transcendence were positively associated with intrinsic academic motivation. CONCLUSIONS: The temperament dimension of persistence and the character dimensions of self-directedness and self-transcendence are associated with intrinsic academic motivation in medical students.

A two-year follow-up study of chronic fatigue syndrome comorbid with psychiatric disorders.

AIMS: Chronic fatigue syndrome patients often have comorbid psychiatric disorders such as major depressive disorders and anxiety disorders. However, the outcomes of chronic fatigue syndrome and the comorbid psychiatric disorders and the interactions between them are unknown. Therefore, a two-year prospective follow-up study was carried out on chronic fatigue syndrome patients with comorbid psychiatric disorders. METHODS: A total of 155 patients who met the Japanese case definition of chronic fatigue syndrome were enrolled in this study. Comorbid psychiatric disorders were diagnosed according to the Diagnostic and Statistical Manual of Mental Disorders 4th edition criteria. Patients with comorbid psychiatric disorders received psychiatric treatment in addition to medical therapy for chronic fatigue syndrome. Seventy patients participated in a follow-up interview approximately 24 months later. RESULTS: Of the 70 patients with chronic fatigue syndrome, 33 patients were diagnosed as having comorbid psychiatric disorders including 18 major depressive disorders. Sixteen patients with psychiatric disorders and eight patients with major depressive disorders did not fulfill the criteria of any psychiatric disorders at the follow up. As for chronic fatigue syndrome, nine out of the 70 patients had recovered at the follow up. There is no significant influence of comorbid psychiatric disorders on the outcome of chronic fatigue syndrome. CONCLUSIONS: Chronic fatigue syndrome patients have a relatively high prevalence of comorbid psychiatric disorders, especially major depressive disorders. The outcomes of chronic fatigue syndrome and psychiatric disorders are independent. Therefore treatment of comorbid psychiatric disorders is necessary in addition to the medical treatment given for chronic fatigue syndrome.

[Estimation of fatigue state in patient with CFS using actigraph and R-R interval power spectrum analysis].

OBJECTIVES: In this study, we try to estimate the fatigue state using actigraphy and R-R interval power spectrum analysis. RESULTS: Actigraphy analysis showed that mean awake activity was decreased and duration of sleep was prolonged in patients with chronic fatigue syndrome (CFS), significantly (p < 0.001). Both of sleep episodes in wake period and wake episodes in sleep period were significantly increased in CFS patients in comparison with healthy volunteers (p < 0.001) In autonomic nerve analysis, sleep/awake ratio of high frequency component was significantly decreased in patients with CFS (p < 0.05). CONCLUSION: The quality of sleep in patients with CFS was decreased because of increase of wake episodes in sleep period. Also the lack of parasympathetic activation during sleep period might be associated with the deterioration of sleep quality in patients with CFS.

Index markers of chronic fatigue syndrome with dysfunction of TCA and urea cycles.

Chronic fatigue syndrome (CFS) is a persistent and unexplained pathological state characterized by exertional and severely debilitating fatigue, with/without infectious or neuropsychiatric symptoms, lasting at least 6 consecutive months. Its pathogenesis remains incompletely understood. Here, we performed comprehensive metabolomic analyses of 133 plasma samples obtained from CFS patients and healthy controls to establish an objective diagnosis of CFS. CFS patients exhibited significant differences in intermediate metabolite concentrations in the tricarboxylic acid (TCA) and urea cycles. The combination of ornithine/citrulline and pyruvate/isocitrate ratios discriminated CFS patients from healthy controls, yielding area under the receiver operating characteristic curve values of 0.801 (95% confidential interval [CI]: 0.711-0.890, P < 0.0001) and 0.750 (95% CI: 0.584-0.916, P = 0.0069) for training (n = 93) and validation (n = 40) datasets, respectively. These findings provide compelling evidence that a clinical diagnostic tool could be developed for CFS based on the ratios of metabolites in plasma.

Frontier studies on fatigue, autonomic nerve dysfunction, and sleep-rhythm disorder.

Fatigue is defined as a condition or phenomenon of decreased ability and efficiency of mental and/or physical activities, caused by excessive mental or physical activities, diseases, or syndromes. It is often accompanied by a peculiar sense of discomfort, a desire to rest, and reduced motivation, referred to as fatigue sensation. Acute fatigue is a normal condition or phenomenon that disappears after a period of rest; in contrast, chronic fatigue, lasting at least 6 months, does not disappear after ordinary rest. Chronic fatigue impairs activities and contributes to various medical conditions, such as cardiovascular disease, epileptic seizures, and death. In addition, many people complain of chronic fatigue. For example, in Japan, more than one third of the general adult population complains of chronic fatigue. It would thus be of great value to clarify the mechanisms underlying chronic fatigue and to develop efficient treatment methods to overcome it. Here, we review data primarily from behavioral, electrophysiological, and neuroimaging experiments related to neural dysfunction as well as autonomic nervous system, sleep, and circadian rhythm disorders in fatigue. These data provide new perspectives on the mechanisms underlying chronic fatigue and on overcoming it.

Reduction of [11C](+)3-MPB binding in brain of chronic fatigue syndrome with serum autoantibody against muscarinic cholinergic receptor.

BACKGROUND: Numerous associations between brain-reactive antibodies and neurological or psychiatric symptoms have been proposed. Serum autoantibody against the muscarinic cholinergic receptor (mAChR) was increased in some patients with chronic fatigue syndrome (CFS) or psychiatric disease. We examined whether serum autoantibody against mAChR affected the central cholinergic system by measuring brain mAChR binding and acetylcholinesterase activity using positron emission tomography (PET) in CFS patients with positive [CFS(+)] and negative [CFS(-)] autoantibodies. METHODOLOGY: Five CFS(+) and six CFS(-) patients, as well as 11 normal control subjects underwent a series of PET measurements with N-[(11)C]methyl-3-piperidyl benzilate [(11)C](+)3-MPB for the mAChR binding and N-[(11)C]methyl-4-piperidyl acetate [(11)C]MP4A for acetylcholinesterase activity. Cognitive function of all subjects was assessed by neuropsychological tests. Although the brain [(11)C](+)3-MPB binding in CFS(-) patients did not differ from normal controls, CFS(+) patients showed significantly lower [(11)C](+)3-MPB binding than CFS(-) patients and normal controls. In contrast, the [(11)C]MP4A index showed no significant differences among these three groups. Neuropsychological measures were similar among groups. CONCLUSION: The present results demonstrate that serum autoantibody against the mAChR can affect the brain mAChR without altering acetylcholinesterase activity and cognitive functions in CFS patients.

Medial orbitofrontal cortex is associated with fatigue sensation.

Fatigue is an indispensable bioalarm to avoid exhaustive state caused by overwork or stresses. It is necessary to elucidate the neural mechanism of fatigue sensation for managing fatigue properly. We performed H(2) ( 15)O positron emission tomography scans to indicate neural activations while subjects were performing 35-min fatigue-inducing task trials twice. During the positron emission tomography experiment, subjects performed advanced trail-making tests, touching the target circles in sequence located on the display of a touch-panel screen. In order to identify the brain regions associated with fatigue sensation, correlation analysis was performed using statistical parametric mapping method. The brain region exhibiting a positive correlation in activity with subjective sensation of fatigue, measured immediately after each positron emission tomography scan, was located in medial orbitofrontal cortex (Brodmann's area 10/11). Hence, the medial orbitofrontal cortex is a brain region associated with mental fatigue sensation. Our findings provide a new perspective on the neural basis of fatigue.

A functional polymorphism in the disrupted-in schizophrenia 1 gene is associated with chronic fatigue syndrome.

AIMS: Disrupted-in schizophrenia 1 (DISC1), identified in a pedigree with a familial psychosis with the chromosome translocation (1:11), is a putative susceptibility gene for psychoses such as schizophrenia and major depressive disorder (MDD). Patients with chronic fatigue syndrome (CFS) report having continuous severe fatigue and many overlapping symptoms with MDD; however, the mechanism and effective treatment of CFS are still unclear. We focused on the overlapping symptoms between CFS and MDD and performed an association study of the functional single-nucleotide polymorphism (SNP) in the DISC1 gene with CFS. MAIN METHODS: Venous blood was drawn from CFS patients and controls and genomic DNA was extracted from the whole blood according to standard procedures. Ser704Cys DISC1 SNP was genotyped using the TaqMan 5'-exonuclease allelic discrimination assay. KEY FINDINGS: We found that the Cys704 allele of Ser704Cys SNP was associated with an increased risk of CFS development compared with the Ser704 allele. SIGNIFICANCE: DISC1 Ser704Cys might be a functional variant that affects one of the mechanisms implicated in the biology of CFS. Some patients with CFS showed a phenotype similar to that of patients with MDD, but further studies are needed to clarify the biological mechanism, because this study is of a rather preliminary nature. Despite the variety of patients with CFS, DISC1 Ser704Cys has an association with CFS, which may also suggest that DISC1 plays a central role in the induction of various psychiatric diseases.

Visible and near-infrared spectral changes in the thumb of patients with chronic fatigue syndrome.

BACKGROUND: Chronic fatigue syndrome (CFS) patients show a persistent fatigue condition with muscle pain and impairment of concentration, memory, and sleep. Presently, the physiological basis of CFS remains unclear. In this study, spectroscopic differences in the thumb were compared between 103 CFS patients and 122 healthy controls to examine possible changes of levels of oxygenated or deoxygenated hemoglobin. METHODS: Visible and near-infrared (Vis-NIR) spectroscopy was used to examine possible changes in the region of 600-1100 nm. RESULTS: Vis-NIR spectra showed sharp peaks at 694, 970 and 1060 nm and broad peaks in the regions of 740-760 and 830-850 nm. As these peaks are possibly related to oxyhemoglobin, cytochrome c oxidase and water, levels of these factors were compared between the two groups. Statistical analysis of the absorbance of Vis-NIR spectra showed a significant decrease in water content, a significant increase in oxyhemoglobin content, and a significant increase in the oxidation of heme a+a(3) and copper in cytochrome c oxidase in CFS patients. CONCLUSIONS: These changes imply accelerated blood flow and energy metabolism in the thumbs of CFS patients.

Spectroscopic diagnosis of chronic fatigue syndrome by visible and near-infrared spectroscopy in serum samples.

To investigate visible and near-infrared (Vis-NIR) spectroscopy enabling chronic fatigue syndrome (CFS) diagnosis, we subjected sera from CFS patients as well as healthy donors to Vis-NIR spectroscopy. Vis-NIR spectra in the 600-1100 nm region for sera from 77 CFS patients and 71 healthy donors were subjected to principal component analysis (PCA) and soft independent modeling of class analogy (SIMCA) to develop multivariate models to discriminate between CFS patients and healthy donors. The model was further assessed by the prediction of 99 masked other determinations (54 in the healthy group and 45 in the CFS patient group). The PCA model predicted successful discrimination of the masked samples. The SIMCA model predicted 54 of 54 (100%) healthy donors and 42 of 45 (93.3%) CFS patients of Vis-NIR spectra from masked serum samples correctly. These results suggest that Vis-NIR spectroscopy for sera combined with chemometrics analysis could provide a promising tool to objectively diagnose CFS.