Loss of disability-adjusted life years due to heat-related sleep disturbance in the Japanese.

The purpose of this study was to quantify the sleep disturbances caused by climate change using disability-adjusted life years (DALY). The revised sleep quality index for daily sleep (SQIDS2), a self-administered questionnaire for daily sleep quality, was developed to assess daily sleep disturbances. This questionnaire referenced and simplified the Pittsburgh Sleep Quality Index (PSQI). This study was conducted in Nagoya City in August 2011 and 2012. Sleep quality was measured using SQIDS2 and PSQI. A total of 574 participants in 2011 and 710 in 2012 responded to the survey. The sleep disturbance prevalence calculated from the SQIDS2 score was correlated with the daily minimum temperature (p = 0.0067). This score increased when the daily minimum temperature was above 24.8 °C. When correcting for the PSQI score, DALY loss due to heat-related sleep disturbances in Nagoya City (population: 2,266,851) was estimated to be 81.8 years in 2012. This value was comparable to the DALY loss due to heatstroke. Sleep disturbance due to climate change was quantified using the DALY based on the PSQI. Legislators must recognize the critical impact of the damage caused by sleep disturbances due to high temperatures at night. Additionally, a daily minimum temperature of 25 °C should be the starting point when establishing a goal or guideline for nighttime temperature.

Protein Composition of Circulating Extracellular Vesicles Immediately Changed by Particular Short Time of High-Intensity Interval Training Exercise.

INTRODUCTION/PURPOSE: High-intensity interval training (HIIT) promotes various biological processes and metabolic effects in multiple organs, but the role of extracellular vesicles (EVs) released from a variety of cells is not fully understood during HIIT exercise (HIIT-Ex). We investigated the changes in circulating number and proteomic profile of EVs to assess the effect of HIIT-Ex. METHODS: Seventeen young men (median age, 20 years) were enrolled in the study. Total duration of the HIIT-Ex was 4 min. Blood samples were collected from before HIIT-Ex (pre-HIIT-Ex), at the immediate conclusion of HIIT-Ex (T0), at 30 min (T30), and at 120 min after HIIT-Ex. The pulse rate and systolic blood pressure were measured. Circulating EVs were characterized, and EV proteins were detected via nano liquid chromatography tandem mass spectrometry. RESULTS: The pulse rate and systolic blood pressure at T0 to pre-HIIT-Ex were significantly higher. Circulating EV number was significantly altered throughout the HIIT-Ex, and the source of circulating EVs included skeletal muscle, hepatocytes, and adipose tissue. Proteomic analysis identified a total of 558 proteins within isolated circulating EVs from pre-HIIT-Ex, T0, and T30. Twenty proteins in total were significantly changed at pre-HIIT-Ex, T0, and T30 and are involved in a variety of pathways, such as activation of coagulation cascades, cellular oxidant detoxification, and correction of acid-base imbalance. Catalase and peroxiredoxin II were increased at T0. CONCLUSION: The circulating EV composition can be immediately changed by particularly a short time of HIIT-Ex, indicating that EVs may intercommunicate across various organs rapidly in response to HIIT-Ex.

Deep phenotyping of myalgic encephalomyelitis/chronic fatigue syndrome in Japanese population.

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a complex and debilitating disease with no molecular diagnostics and no treatment options. To identify potential markers of this illness, we profiled 48 patients and 52 controls for standard laboratory tests, plasma metabolomics, blood immuno-phenotyping and transcriptomics, and fecal microbiome analysis. Here, we identified a set of 26 potential molecular markers that distinguished ME/CFS patients from healthy controls. Monocyte number, microbiome abundance, and lipoprotein profiles appeared to be the most informative markers. When we correlated these molecular changes to sleep and cognitive measurements of fatigue, we found that lipoprotein and microbiome profiles most closely correlated with sleep disruption while a different set of markers correlated with a cognitive parameter. Sleep, lipoprotein, and microbiome changes occur early during the course of illness suggesting that these markers can be examined in a larger cohort for potential biomarker application. Our study points to a cluster of sleep-related molecular changes as a prominent feature of ME/CFS in our Japanese cohort.

Identification of actin network proteins, talin-1 and filamin-A, in circulating extracellular vesicles as blood biomarkers for human myalgic encephalomyelitis/chronic fatigue syndrome.

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a serious, debilitating disorder with a wide spectrum of symptoms, including pain, depression, and neurocognitive deterioration. Over 17 million people around the world have ME/CFS, predominantly women with peak onset at 30-50 years. Given the wide spectrum of symptoms and unclear etiology, specific biomarkers for diagnosis and stratification of ME/CFS are lacking. Here we show that actin network proteins in circulating extracellular vesicles (EVs) offer specific non-invasive biomarkers for ME/CFS. We found that circulating EVs were significantly increased in ME/CFS patients correlating to C-reactive protein, as well as biological antioxidant potential. Area under the receiver operating characteristic curve for circulating EVs was 0.80, allowing correct diagnosis in 90-94% of ME/CFS cases. From two independent proteomic analyses using circulating EVs from ME/CFS, healthy controls, idiopathic chronic fatigue, and depression, proteins identified from ME/CFS patients are involved in focal adhesion, actin skeletal regulation, PI3K-Akt signaling pathway, and Epstein-Barr virus infection. In particular, talin-1, filamin-A, and 14-3-3 family proteins were the most abundant proteins, representing highly specific ME/CFS biomarkers. Our results identified circulating EV number and EV-specific proteins as novel biomarkers for diagnosing ME/CFS, providing important information on the pathogenic mechanisms of ME/CFS.

[Subjective happiness among Japanese adults: An upward tendency associated with age].

Objectives　The present study investigated subjective happiness in Japanese adults and offers basic knowledge for future studies. In addition, how subjective happiness varies in relation to certain demographic variables, such as gender and age, as well as factors that influence this variability, are examined.Methods　A total of 2,000 Japanese people (1,000 females and 1,000 males) over the age of 20 completed an anonymous self-report internet survey. There were approximately the same number of participants in each of six age groups ranging from the 20s to 70s. How Subjective Happiness Scale (SHS) scores were related to various demographic variables, including gender and age, as well as happiness, life satisfaction, and stress response, were analyzed.Results　The validity of the SHS was supported by positive correlations with happiness and life satisfaction scores and negative correlation with stress response scores. The results also showed that females had higher SHS scores than males, and this gender difference was distinctive, especially among young adults. In addition, there was a U-shaped change in SHS score by age. That is, subjective happiness dropped with age, but started increasing again after the 50s. The same findings were reconfirmed by an additional survey one year later. Moreover, those with a spouse showed higher SHS scores than unmarried participants. Lastly, SHS scores were low among those whose highest education was junior high school and those who lived alone, although the limitations of sampling bias should be considered.Conclusion　The SHS is an internationally accepted measure of subjective happiness consisting of only four items and can easily be used in public health research and practice. The current study offers basic information regarding SHS scores as well as subjective happiness in Japanese adults of different age groups and genders. The findings of the present study clearly indicate higher levels of subjective happiness among older age groups than younger ones, those with a spouse than those without a spouse, and females than males. As many studies conducted in other cultures have shown no such gender difference, further cross-cultural comparison studies are needed to clarify this discrepancy. The SHS as an indicator of personal well-being can be strongly expected to show extended utility in the future.

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.

A potential biomarker for fatigue: Oxidative stress and anti-oxidative activity.

We sought to determine whether oxidative stress and anti-oxidative activity could act as biomarkers that discriminate patients with chronic fatigue syndrome (CFS) from healthy volunteers at acute and sub-acute fatigue and resting conditions. We calculated the oxidative stress index (OSI) from reactive oxygen metabolites-derived compounds (d-ROMs) and the biological antioxidant potential (BAP). We determined changes in d-ROMs, BAP, and OSI in acute and sub-acute fatigue in two healthy groups, and compared their values at rest between patients with CFS (diagnosed by Fukuda 1994 criteria) and another group of healthy controls. Following acute fatigue in healthy controls, d-ROMs and OSI increased, and BAP decreased. Although d-ROMs and OSI were significantly higher after sub-acute fatigue, BAP did not decrease. Resting condition yielded higher d-ROMs, higher OSI, and lower BAP in patients with CFS than in healthy volunteers, but lower d-ROMs and OSI when compared with sub-acute controls. BAP values did not significantly differ between patients with CFS and controls in the sub-acute condition. However, values were significantly higher than in the resting condition for controls. Thus, measured of oxidative stress (d-ROMS) and anti-oxidative activity (BAP) might be useful for discriminating acute, sub-acute, and resting fatigue in healthy people from patients with CFS, or for evaluating fatigue levels in healthy people.

Ubiquinol-10 supplementation improves autonomic nervous function and cognitive function in chronic fatigue syndrome.

The aim of this study was to evaluate the benefit of oral ubiquinol-10 supplementation in CFS patients using an open-label study and a randomized, double-blinded, placebo-controlled (RCT) study. Twenty patients with CFS were randomly enrolled in an 8-week open-label oral ubiquinol-10 (150 mg ubiquinol-10/day) study. The patients and the attending physicians were not blinded to the supplementation. Forty-three patients with CFS were randomly assigned to receive either ubiquinol-10 (150 mg/day) or placebo every day for 12 weeks. The patients and the attending physicians were blinded to the supplementation, and a total of 31 patients (N = 17 in the ubiquinol group and 14 in the placebo group) completed the study. The beneficial effects of ubiquinol-10 were observed in the open-label study we conducted prior to the RCT. The RCT results suggest that supplementation with ubiquinol-10 for 12 weeks is effective for improving several CFS symptoms. © 2016 BioFactors, 42(4):431-440, 2016.

Effects of nutritional supplementation on fatigue, and autonomic and immune dysfunction in patients with end-stage renal disease: a randomized, double-blind, placebo-controlled, multicenter trial.

BACKGROUND: Fatigue is a predictor of cardiovascular events in patients with end-stage renal disease (ESRD) undergoing hemodialysis treatment. We hypothesized that multinutritional support would improve quality of life, fatigue symptoms, and potential quantitative measures including endocrine, immune and autonomic functions in patients with ESRD undergoing hemodialysis. METHODS: Two hundred and two hemodialysis patients were randomly assigned to receive active treatment (containing vitamin B1, vitamin B2, niacin, vitamin B6, vitamin B12, folic acid, vitamin C, carnitine, coenzyme Q10, naïve galacto-oligosaccharide, and zinc) or placebo after each dialysis session for 12 weeks. The patients and attending physicians were blinded to the treatment, and 172 patients (86 in each group) completed the study. Fatigue was evaluated via fatigue questionnaire at 0, 4, and 12 weeks. To assess human herpes virus (HHV) 6 and 7 reactivation, numbers of viral DNA copies were determined in saliva by polymerase chain reaction at weeks 0 and 12. Autonomic function was determined via measurement of beat-to-beat variation by using acceleration plethysmography. RESULTS: Clinical characteristics, changes in fatigue, quality of life score, endocrine functions, and laboratory data did not differ significantly between the two groups. Several parameters of heart rate variability significantly increased after nutritional treatment compared to placebo. Nutritional drink for 12 weeks significantly suppressed HHV7 DNA copy numbers. Similarly, HHV6 DNA copy numbers tended to be decreased by treatment but without reaching statistical significance. CONCLUSIONS: Nutritional supplementation may modulate immune and autonomic dysfunction in ESRD patients undergoing hemodialysis.

Fatigue and sleep under large summer temperature differences.

BACKGROUND: It has been recognized that an increase in outdoor ambient temperatures has a negative impact on health, particularly fatigue and sleep quality; however, the relationship among fatigue, sleep quality, and air temperature has yet to be sufficiently elucidated. OBJECTIVES: To examine whether fatigue and sleep quality in a healthy Japanese population were affected by rising air temperature at three time points in summer and to investigate the confounding factors for fatigue. METHODS: A total of 602 healthy volunteers in Osaka, Japan, participated in a survey that was conducted at the end of July, August, and September in 2010. The questionnaire consisted of four sections; demographic variables, accommodation status, fatigue, and sleep quality. We used the Chalder fatigue scale for assessment of fatigue, and the Japanese version of the Pittsburgh Sleep Quality Index (PSQI) for assessment of sleep quality. RESULTS: The fatigue score was positively correlated with the sleep quality score in the total cohort. All the questionnaires at the three time points were completed by 162 participants. There were significant differences in fatigue scores among the surveys. We stratified the subjects into two groups of good and poor sleepers using a cutoff value of the PSQI. The good sleepers did not show differences in fatigue score regardless of the change in air temperature. However, the fatigue score of poor sleepers was greater at higher air temperatures. The use of air conditioners, accommodation type, and subject's age were confounding factors for fatigue. CONCLUSIONS: High air temperatures in summer increased fatigue in healthy volunteers, especially those with poor sleep patterns, depending on the use of air conditioners, accommodation status, and subject's age.

Neuroinflammation in Patients with Chronic Fatigue Syndrome/Myalgic Encephalomyelitis: An ¹¹C-(R)-PK11195 PET Study.

UNLABELLED: Chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME) is a disease characterized by chronic, profound, disabling, and unexplained fatigue. Although it is hypothesized that brain inflammation is involved in the pathophysiology of CFS/ME, there is no direct evidence of neuroinflammation in patients with CFS/ME. Activation of microglia or astrocytes is related to neuroinflammation. (11)C-(R)-(2-chlorophenyl)-N-methyl-N-(1-methylpropyl)-3-isoquinoline-carboxamide ((11)C-(R)-PK11195) is a ligand of PET for a translocator protein that is expressed by activated microglia or astrocytes. We used (11)C-(R)-PK11195 and PET to investigate the existence of neuroinflammation in CFS/ME patients. METHODS: Nine CFS/ME patients and 10 healthy controls underwent (11)C-(R)-PK11195 PET and completed questionnaires about fatigue, fatigue sensation, cognitive impairments, pain, and depression. To measure the density of translocator protein, nondisplaceable binding potential (BP(ND)) values were determined using linear graphical analysis with the cerebellum as a reference region. RESULTS: The BP(ND) values of (11)C-(R)-PK11195 in the cingulate cortex, hippocampus, amygdala, thalamus, midbrain, and pons were 45%-199% higher in CFS/ME patients than in healthy controls. In CFS/ME patients, the BP(ND) values of (11)C-(R)-PK11195 in the amygdala, thalamus, and midbrain positively correlated with cognitive impairment score, the BP(ND) values in the cingulate cortex and thalamus positively correlated with pain score, and the BP(ND) value in the hippocampus positively correlated with depression score. CONCLUSION: Neuroinflammation is present in widespread brain areas in CFS/ME patients and was associated with the severity of neuropsychologic symptoms. Evaluation of neuroinflammation in CFS/ME patients may be essential for understanding the core pathophysiology and for developing objective diagnostic criteria and effective medical treatments.

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.

Divided attention of adolescents related to lifestyles and academic and family conditions.

BACKGROUND: Development of the ability to divide attention is of crucial importance in the transitional period from elementary to junior high school. The relationship between divided attention and the prevalence of fatigue or low academic motivation is observed in junior high school students. In order to clarify the factors underlying decreased ability to divide attention, we examined the relationships between divided attention, as assessed by the kana pick-out test, lifestyle factors, and academic and family conditions in junior high school students. METHODS: The study group consisted of 158 healthy 1st-, 2nd-, and 3rd-grade level junior high school students. Each participant performed the kana pick-out test and questionnaires dealing with lifestyle factors (nocturnal sleeping hours on school days, breakfast, exercise, watching television, and spending time with family members), and academic and family conditions (good friendships at school and praise from family members when participants showed good academic performance). RESULTS: On multiple regression analyses adjusted for grade and gender, scores on the kana pick-out test were positively associated with spending time with family members. In addition, the comprehension score of the kana pick-out test was positively associated with having breakfast every day and praise by family members. The score was negatively associated with watching television. CONCLUSION: The present findings suggest that the ability to divide attention is independently associated with good lifestyles and academic and family conditions in junior high school students.

Association of monoamine-synthesizing genes with the depression tendency and personality in chronic fatigue syndrome patients.

AIMS: Tyrosine hydroxylase (TH) and GTP cyclohydrolase I (GCH) are the rate-limiting enzymes for the biosynthesis of catecholamines and tetrahydrobiopterin (BH4), respectively. Since catecholamines and BH4 are thought to be involved in the pathophysiology of CFS, we explored the genetic factors that influence CFS development and examined the possible association between the SNPs of the TH and GCH genes and the various characteristics of CFS patients. MAIN METHODS: After drawing venous blood from CFS patients and controls, genomic DNA was then extracted from whole blood in accordance with standard procedures. Digestion patterns of the PCR products were used for genotyping the SNPs of GCH (rs841; C+243T) and TH (rs10770141; C-824T). We also performed questionnaires consisting of fatigue-scale and temperament and character inventory scale (TCI) to CFS patients. KEY FINDINGS: Our results demonstrated that the allele differences for the GCH and TH SNPs were not associated with CFS patients. We did find that the GCH gene with the C+243T polymorphism affected harm avoidance, while the TH gene with the C-824T polymorphism affected persistence in the CFS patients. The concept of persistence has been linked to specific personality, such as perfectionism, in CFS. SIGNIFICANCE: Our results suggest that the biosynthetic pathways of the monoamine neurotransmitters that are mediated by TH and GCH might be associated with the CFS clinical findings, because persistence is one of the typical personality traits observed in CFS and patients with major depressive disorder exhibit a higher harm avoidance score.

Low visual information-processing speed and attention are predictors of fatigue in elementary and junior high school students.

BACKGROUND: Fatigue is a common complaint among elementary and junior high school students, and is known to be associated with reduced academic performance. Recently, we demonstrated that fatigue was correlated with decreased cognitive function in these students. However, no studies have identified cognitive predictors of fatigue. Therefore, we attempted to determine independent cognitive predictors of fatigue in these students. METHODS: We performed a prospective cohort study. One hundred and forty-two elementary and junior high school students without fatigue participated. They completed a variety of paper-and-pencil tests, including list learning and list recall tests, kana pick-out test, semantic fluency test, figure copying test, digit span forward test, and symbol digit modalities test. The participants also completed computerized cognitive tests (tasks A to E on the modified advanced trail making test). These cognitive tests were used to evaluate motor- and information-processing speed, immediate and delayed memory function, auditory and visual attention, divided and switching attention, retrieval of learned material, and spatial construction. One year after the tests, a questionnaire about fatigue (Japanese version of the Chalder Fatigue Scale) was administered to all the participants. RESULTS: After the follow-up period, we confirmed 40 cases of fatigue among 118 students. In multivariate logistic regression analyses adjusted for grades and gender, poorer performance on visual information-processing speed and attention tasks was associated with increased risk of fatigue. CONCLUSIONS: Reduced visual information-processing speed and poor attention are independent predictors of fatigue in elementary and junior high school students.

Cognitive dysfunction and mental fatigue in childhood chronic fatigue syndrome--a 6-month follow-up study.

OBJECTIVES: Cognitive function was investigated in patients with childhood type chronic fatigue syndrome (CCFS) using the modified advanced trail making test (mATMT). METHODS: mATMT was performed on 19 patients with CCFS and 25 healthy controls of comparable age and sex. The effectiveness of combined treatment with cognitive behavioral therapy (CBT) and pharmacotherapy and its relationship to cognitive function was investigated by evaluation of Chalder's fatigue scale and behavior state before and after treatment for 6 consecutive months. RESULTS: All three tasks (motor skill, selective and alternative attention, and spatial working memory) of the mATMT, especially the difference in reaction time of the alternative attention task, could discriminate CCFS patients from control subjects with 70.5% accuracy (P=0.007). CCFS patients showed significantly lower alternative attention and Chalder's fatigue score before treatment (P=0.037 and 0.002, respectively). A significant improvement in performance status scores was found during the 6 months follow-up period with combined treatment with CBT and medication (P<0.001). Improvement of their cognitive symptoms was significantly correlated with improvement of alternative attention (r=0.653, P=0.002). CONCLUSIONS: Higher-order level cognitive dysfunction affects CCFS pathogenesis. Alternative attention performance evaluated by the mATMT may be used to monitor improvement in patients with CCFS. Combined treatment with CBT and medication may be effective to improve poor attention characteristics associated with CCFS.

Relationship between cognitive function and prevalence of decrease in intrinsic academic motivation in adolescents.

BACKGROUND: Decrease in intrinsic motivation is a common complaint among elementary and junior high school students, and is related to poor academic performance. Since grade-dependent development of cognitive functions also influences academic performance by these students, we examined whether cognitive functions are related to the prevalence of decrease in intrinsic academic motivation. METHODS: The study group consisted of 134 elementary school students from 4th to 6th grades and 133 junior high school students from 7th to 9th grades. Participants completed a questionnaire on intrinsic academic motivation. They also performed paper-and-pencil and computerized cognitive tests to measure abilities in motor processing, spatial construction, semantic fluency, immediate memory, short-term memory, delayed memory, spatial working memory, and selective, alternative, and divided attention. RESULTS: In multivariate logistic regression analyses adjusted for grade and gender, scores of none of the cognitive tests were correlated with the prevalence of decrease in intrinsic academic motivation in elementary school students. However, low digit span forward test score and score for comprehension of the story in the kana pick-out test were positively correlated with the prevalence of decrease in intrinsic academic motivation in junior high school students. CONCLUSIONS: The present findings suggest that decrease in capacity for verbal memory is associated with the prevalence of decrease in intrinsic academic motivation among junior high school students.

Relationship between cognitive functions and prevalence of fatigue in elementary and junior high school students.

BACKGROUND: Fatigue is a common complaint among elementary and junior high school students, and is related to poor academic performance. Since grade-dependent development of cognitive functions also influences academic performance, we attempted to determine whether cognitive functions were associated with the prevalence of fatigue. METHODS: Participants were 148 elementary school students from 4th- to 6th-grades and 152 junior high school students from 7th- to 9th-grades. Participants completed a questionnaire about fatigue (Japanese version of the Chalder Fatigue Scale) and paper-and-pencil and computerized cognitive tests which could evaluate the abilities of motor processing, immediate, delayed and working memory, selective, divided and alternative attention, retrieve learned material, and spatial construction. RESULTS: We found that in multivariate logistic regression analyses adjusted for grade and gender, slow motor processing was positively correlated with the prevalence of fatigue in the elementary school students and decreases in working memory and divided and alternative attention processing were positively correlated with the prevalence of fatigue in the junior high school students. CONCLUSION: The grade-dependent development of cognitive function influences the severity of fatigue in elementary and junior high school students.

Changes in cognitive functions of students in the transitional period from elementary school to junior high school.

BACKGROUND: When students proceed to junior high school from elementary school, rapid changes in the environment occur, which may cause various behavioral and emotional problems. However, the changes in cognitive functions during this transitional period have rarely been studied. METHODS: In 158 elementary school students from 4th- to 6th-grades and 159 junior high school students from 7th- to 9th-grades, we assessed various cognitive functions, including motor processing, spatial construction ability, semantic fluency, immediate memory, delayed memory, spatial and non-spatial working memory, and selective, alternative, and divided attention. RESULTS: Our findings showed that performance on spatial and non-spatial working memory, alternative attention, divided attention, and semantic fluency tasks improved from elementary to junior high school. In particular, performance on alternative and divided attention tasks improved during the transitional period from elementary to junior high school. CONCLUSION: Our finding suggests that development of alternative and divided attention is of crucial importance in the transitional period from elementary to junior high school.

Personality and fatigue in medical students.

Among medical students, fatigue is a common complaint and is related to poor academic outcomes. Associations of scores on personality traits and fatigue in medical students were examined. A group of 125 healthy second-year medical students completed a questionnaire about fatigue, the Japanese version of the Chalder Fatigue Scale, and the Temperament and Character Inventory. On simple regression analyses, the Temperament and Character Inventory dimension of Harm Avoidance was positively associated with Fatigue scores and those on Self-directedness were negatively associated. Similarly, on multiple regression analyses adjusted for age and sex, scores on the Temperament and Character Inventory dimension of Harm Avoidance were positively associated with Fatigue scores, and those for Self-directedness were negatively associated. These correlations were evident even after adjustment for other Temperament and Character Inventory dimensions. The temperament dimension of Harm Avoidance and the character dimension of Self-directedness were both associated with Fatigue in medical students.