جستجوی مقالات مرتبط با کلیدواژه "chronotype" در نشریات گروه "پزشکی"

The present study aimed to investigate the role of chronotype predictability in the working memory of female students using the Cambridge Neuropsychological Test Automated Battery.

The statistical population consisted of 180 female students in the first to third grades at Tawheed School in Shahrood City for the academic year 2023-2024. These students were selected using an available sampling method and were assessed during the morning shift. The Children's Chronotype Questionnaire (CCTQ) was used to measure chronotype, while the Cambridge Neuropsychological Assessment Test was used to evaluate students' working memory. Data analysis involved correlation coefficient tests and stepwise regression analysis carried out using SPSS-22 statistical software.

The study found a significant positive relationship between working memory parameters—such as errors and strategies—and chronotype questionnaire indicators, particularly the midpoint of sleep and the morning/eveningness component. Outstandingly, the morning/eveningness component had a correlation of 87/87 for errors and 1B/03 for strategies, while waking time on working days correlated with errors at 0.14 and strategies at 0.1B, signifying they may predict working memory performance. On the contrary, the results indicated that girls with a morning chronotype demonstrated fewer errors and more effective strategies compared to those with intermediate and evening chronotypes (P<0.05). Furthermore, older students (9 years old) exhibited fewer errors and better strategies, with these age-related differences being statistically significant.

The results highlight the importance of considering circadian rhythm factors in evaluating students' learning. Recognizing individual differences in morning and evening preferences can be favorable for designing effective educational programs.

Human cognitive activities are affected by the time of doing homework, biologic rhythms and interaction among them.

this research accomplished to specify the fluctuation patterns of daily and weekly cycles of the students attention. The research method was correlation. The statistical population of this study were 45 female students in 11th grade from a high school in humanities branch from khodabandeh city in 2017- 2018 academic year, that have been selected through randomized cluster sampling method at two works in a rotational shiftwork at two times on mornings (8, 9/30, and 11 a. m) and afternoons( 13, 14/30 and 16/15 p. m). Horn and Ostberg questionnaire was used for evaluation of the chronotype of students and for the attention assessment the parallel forms of the d2 test administered. The mixed analysis of variance was used to analyze data.

there was a significant difference between efficiency of students' attention at different times of day and also difference in efficiency of students' attention in the morning, midday and evening chronotypes. Efficiency of students' attention was different in chronotypes at different hours of the day.

regarding the differences of efficiency of students' attention in circadian and weekly rhythms and also individual differences, it is necessary to consider them in teaching and learning process in educational environments.

Introduction and

According to the past studies, balance dysfunction may increase the risk of injury and falling among elderly. Several studies have examined factors that influencing balance acuity; however, the impact of different hours of the day on performance of this function is unknown. The purpose of this study was to evaluate the effect of 2 different time of day on the accuracy of the static and dynamic balance among elderly men of Kerman.

15 elderly men with an average age of 68.09 ± 6.34 years old, height 171.23 ± 6.99 cm and weight 75.12 ± 10.54 based on inclusion and exclusion criteria of the study were selected between 60 participant as subjects of study. After they filled the chronotype questionnaire all of them were tested by stork test and time up/go test for static and dynamic variables evaluations at 2 different times of day(morning:7.30 and afternoon:17), and for comparing data variances in different times repeated measures ANOVA has been used.

Despite the different records at different times of day and also decreasing in afternoon balance grades, there was no statistically significant difference in static and dynamic balance in different times of day.

According to the results of this study, it appears that the accuracy of balance function of the elderly men with morning habitual chronotype is not affected by circadian rhythm, so, there are no differences in the risk of injury and falling among elderly men due to balance dysfunction while performing physical activities in different hours of day and night. but it is better for the elderly that pay attention more to extrinsic falling factor such as surface of walking track at the end of the day.

In modern societies, shift work is an essential component of daily life. Since the beginning of research in shift work, researchers have been engaged in the identification of factors predicting adjustment and adaptation to shift work. The concept of adaptation and tolerance refers mainly to the biological response in terms of circadian rhythms and performance efficiency as well as sleep duration and quality. Since some of the shift workers show higher level of adaptation in comparison with the others, the individual sensitivity may be a good predictor. The present study was undertaken to specify whether changes in cortisol rythmicity are associated with chronotype, quality of sleep and adaptation to shift work.

This study was cross-sectional. Blood samples were drawn from 57 shift workers. Three sample were drawn from each subject (at the beginning of their night shift, at the end of their night shift and at the beginning of their morning shift). The samples were immediately centrifuged and the plasma was removed and stored at -25 0c until assay. Cortisol was measured by radioimmunoassay using LKV Mili gama counter and Immunotech-IM1841 kit. Also, all subjects completed questionnaires for the acquisition of chronotype, quality of sleep and adaptation to shift work.

The mean age, work experience and BMI of the sample was 33.5+6.2years, 6.2+2.5 years and 24.1+2.8, respectively. 89.5 percent of subjects were married. The mean cortisol level at the beginning of night shift, the end of night shift and the beginning of morning shift was 6.95 Mg/dl,18.31Mg/dl and 19.1Mg/dl, respectively. 83.9 percent of subjects had morning chronotype and 16.1 percent had evening chronotype. The mean cortisol level at the beginning of morning shift and at the beginning and end of night shift for morning and evening subjects were (19.5, 16.5),(6.5,7.7)and(17.1,18.4)Mg/dl. 46 percent of subjects reported good sleep at the morning shift, while others reported moderate and weak sleep. Also, at the night shift, only 21.4 percent showed good sleep.

Although there was a difference between the mean cortisol levels of morning and evening active subjects, but because of small sample size of evening active subjects, statistical analysis showed no significant difference between them. The mean cortisol level at the beginning of morning shift was related to the quality of sleep directly. There was a significant difference between the mean cortisol level at the end of night shift and morning shift sleep score (P=0.035). Also spearman analysis revealed a significant correlation between morning shift sleep score and value of beginning night shift cortisol reduction per end of night shift. There was a correlation between mean cortisol level at the end of night shift and adaptation score. Results showed that as the adaptation score increased, the differences between mean cortisol level at the beginning and the end of their night shift decreased.