Discrimination between extreme chronotypes using the full and reduced version of the Morningness-Eveningness Questionnaire

The aim of this study was to carry out a comparison of the ability to discriminate between extreme chronotypes, i.e., morning- and evening-types, among the Morningness-Eveningness Questionnaire (MEQ) and its reduced version (rMEQ). To this end a secondary analysis of cohort studies, using two different approaches, was carried out. The first, subjective, relied on the computing of overlap between extreme chronotypes according to their hourly ideal bedtime, get-up time and midpoint of sleep reported at the MEQ and rMEQ, while the second, objective, on the corresponding actual-actigraphic times. At the subjective approach, 2706 participants filled in the MEQ, while 940 the rMEQ (age range of both groups: 18–30 years). The overlap was significantly lower among those who filled the rMEQ than MEQ when considering ideal midpoint of sleep (13.70% and 46.28%, respectively) and get-up time (47.04% and 62.34%, respectively). At the objective approach, 51 participants filled in the MEQ while 52 the rMEQ (age range: 19–30 years in both groups) at the end of one week of actigraphic recording. No significantly different overlap across those who filled the MEQ or rMEQ was observed with reference to the examined actigraphic times. Results of subjective assessment showed as rMEQ more clearly discriminated between extreme chronotypes than MEQ. The attempt to find an objective confirmation did not provide the same results, probably as a consequence of a masking effect by social rhythms.     

Premature birth and circadian preference in young adulthood: evidence from two birth cohorts

A preference for eveningness (being a “night owl”) and preterm birth (<37 weeks of gestation) are associated with similar adversities, such as elevated blood pressure, impaired glucose regulation, poorer physical fitness, and lower mood. Yet, it remains unclear if and how preterm birth is associated with circadian preference. The aim of this study was to assess this association across the whole gestation range, using both objective and subjective measurements of circadian preference.

Circadian preference was measured among 594 young adults (mean age 24.3 years, SD 1.3) from two cohorts: the ESTER study and the Arvo Ylppö Longitudinal Study. We compared 83 participants born early preterm (<34 weeks) and 165 late preterm (34 to <37 weeks) with those born at term (≥37 weeks, n = 346). We also compared very low birth weight (VLBW, <1500 g) participants with term-born controls. We obtained objective sleep data with actigraphs that were worn for a mean period of 6.8 (SD 1.4) nights. Our primary outcome was sleep midpoint during weekdays and weekend. The sleep midpoint is the half-way time between falling asleep and waking up, and it represents sleep timing. We also investigated subjective chronotype with the Morningness–Eveningness Questionnaire (MEQ) in 688 (n = 138/221/329) ESTER participants. The MEQ consists of 19 questions, which estimates the respondent to be of a “morning”, “evening,” or “intermediate” chronotype, based on the Morningness–Eveningness Score (MES). We analyzed the data from the actigraphs and the MES with three linear regression models, and analyzed distribution of the chronotype class with Pearson χ2.

There were no consistent differences across the study groups in sleep midpoint. As compared with those born at term, the mean differences in minutes:seconds and 95% confidence intervals for the sleep midpoint were: early preterm weekdays 11:47 (?8:34 to 32:08), early preterm weekend 4:14 (?19:45 to 28:13), late preterm weekdays ?10:28 (?26:16 to 5:21), and late preterm weekend ?1:29 (?20:36 to 17:37). There was no difference in sleep timing between VLBW-participants and controls either. The distribution of chronotype in the MEQ among all participants was 12.4% morningness, 65.4% intermediate, and 22.2% eveningness. The distribution of the subjective chronotype class did not differ between the three gestational age groups (p = 0.98). The linear regression models did not show any influence of gestational age group or VLBW status on the MES (all p > 0.5).

We found no consistent differences between adults born early or late preterm and those born at term in circadian preference. The earlier circadian preference previously observed in those born smallest is unlikely to extend across the whole range of preterm birth.     

Predicting the actigraphy-based acrophase using the Morningness–Eveningness Questionnaire (MEQ) in college students of North Italy

Actigraphy is the reference objective method to measure circadian rhythmicity. One simpler subjective approach to assess the circadian typology is the Morningness–Eveningness Questionnaire (MEQ) by Horne and Ostberg. In this study, we compared the MEQ score against the actigraphy-based circadian parameters MESOR, amplitude and acrophase in a sample of 54 students of the University of Milan in Northern Italy. MEQ and the acrophase resulted strongly and inversely associated (r = ?0.84, p < 0.0001), and their relationship exhibited a clear-cut linear trend. We thus used linear regression to develop an equation enabling us to predict the value of the acrophase from the MEQ score. The parameters of the regression model were precisely estimated, with the slope of the regression line being significantly different from 0 (p < 0.0001). The best-fit linear equation was: acrophase (min) = 1238.7–5.49·MEQ, indicating that each additional point in the MEQ score corresponded to a shortening of the acrophase of approximately 5 min. The coefficient of determination, R², was 0.70. The residuals were evenly distributed and did not show any systematic pattern, thus indicating that the linear model yielded a good, balanced prediction of the acrophase throughout the range of the MEQ score. In particular, the model was able to accurately predict the mean values of the acrophase in the three chronotypes (Morning-, Neither-, and Evening-types) in which the study subjects were categorized. Both the confidence and prediction limits associated to the regression line were calculated, thus providing an assessment of the uncertainty associated with the prediction of the model. In particular, the size of the two-sided prediction limits for the acrophase was about ±100 min in the midrange of the MEQ score. Finally, k-fold cross-validation showed that both the model’s predictive ability on new data and the model’s stability to changes in the data set used for parameter estimation were good. In conclusion, the actigraphy-based acrophase can be predicted using the MEQ score in a population of college students of North Italy.     

Correlation between morningness-eveningness and final school leaving exams

Pupils shift their time of day preferences from morningness to eveningness during the age of puberty. Therefore, early school start times may have a negative influence on school functioning, adolescent health and on grade point average. Here, we show that morningness - eveningness influences school performance as measured by the final school leaving/university entrance certificate. One hundred and thirty-two university students aged between 20 and 22 years participated in our study. We found a highly significant positive correlation between the average grading of the final exam and the morningness score, suggesting that pupils with morning preferences performed better in school achievement. Evening types seem at a serious disadvantage because the final exams are used for university entrance decisions.     

The relationship between morningness-eveningness preference and online learning

This study explored whether circadian preference is related to students' attitudes and choices to attend lectures or watch them online, and whether these variables relate to course performance. The subjects were 847 students enrolled in an introductory psychology course who completed an online survey that contained the Morningness - Eveningness Questionnaire and that ascertained their attitudes towards online lectures and the extent to which they attended lectures or watched them online; course performance was also recorded. The results revealed that evening-type students were significantly more likely to have a positive attitude toward online lectures and to choose to watch lectures online. Course performance was not linked to morningness - eveningness preference, lecture mode choice, or their interaction. The results suggest that online lectures appeal differentially to students with a morning or evening orientation, but that watching lectures in a modality that does not accommodate a student's circadian preference does not handicap performance.     

Halide fluxes in epithelial cells measured with an automated cell plate reader

A method is introduced to measure chloride permeability in cultured epithelial cells using 6-methoxy-N-(3-sulfopropyl)quinolinium (SPQ) and 6-methoxy-N-ethylquinolinium iodide quinolinium (MEQ) as fluorescent chloride-sensitive probes. The method involves growing cells in multiwell plates, incubating cells with SPQ or MEQ, and then exchanging intracellular or extracellular halide ions with nitrate. The resulting time course of SPQ or MEQ fluorescence is followed by repetitive readings with a multiwell fluorescence plate reader. Exchange times are extracted by fitting the time course with a single exponential function of time. The method was validated by measuring the effect of chloride channel activators and blockers in A6 and MDCK cells. The baseline iodide/nitrate exchange time was 200-300 s. Isoproterenol (a modulator of cAMP-activated chloride channels) increased the exchange rate by a factor of 1.4+/-0.1; A23187 (a modulator of calcium-activated chloride channels) increased the rate by 3.4+/-0.4; bradykinin (also a modulator of calcium-activated chloride channels) increased the rate by 2.0+/-0.4; forskolin (a direct stimulator of adenylate cyclase) increased the rate by 2.7+/-0.3. Diphenylamine-2-carboxylate (a chloride channel blocker) decreased the rate by 0.12+/-0.03. These results indicate that our method is a valid indicator of halide-nitrate exchange in cultured epithelial cells.     

Item response analysis of a shortened German version of the morningness–eveningness scale

A shortened version of the German adaptation of the morningness–eveningness scale of Horne and Östberg is analysed within a large sample of 994 physicians with respect to dimensionality, reliability, gender differences and validity. The psychometric analysis – which incorporates a highly robust method to check for unidimensionality – shows discrepancies towards unidimensionality and highlights three misfitting items. In addition, hypothesis testing indicates the presence of differential item functioning (DIF) with respect to gender which could be caused by differences in response formats. Although, reliability estimates are satisfactory, an overall lack of adequate psychometric properties of the scale within the population of physicians has to be reported. We derive suggestions for improvement of the original morningness–eveningness questionnaire (MEQ)-scale and provide general comments on how to check for unidimensionality without imposing a restrictive response model.     

Morningness/Eveningness and Satisfaction With Life in a Polish Sample

Previous studies have provided evidence that eveningness could be related to disadvantageous individual characteristics. The hypothesis that more evening-oriented individuals exhibit lower satisfaction with life has been tested by Randler using a sample of 164 German university students, and this showed that eveningness is associated with lower satisfaction with life (r?=?.177). The aim of the present study was to answer the question of whether or not this relationship is culturally independent, and would exist if a sample from another geographical location and culture had been studied. A sample of 349 residents (149 men) aged between 13 and 59 yrs from two Polish cities completed the Morningness-Eveningness Questionnaire and the Satisfaction with Life Scale. Analysis revealed that morningness was related to greater life satisfaction (r?=?.105), regardless of age and sex. The magnitude of this relationship did not differ significantly between the Polish and the German sample, which suggests that the magnitude and direction of association between morningness/eveningness and satisfaction with life could be independent of culture or geographical location. (Author correspondence: E-mail: konrad.jankowski@psych.uw.edu.pl)     

Validity and reliability of the Slovene version of the Morningness-Eveningness Questionnaire

ABSTRACT

Morningness-eveningness (ME) can be defined as individual differences in sleep-wake patterns, and the time of day people feel and perform best. Various self-report instruments that measure ME have been developed. The Horne and Östberg Morningness-Eveningness Questionnaire (MEQ) has most frequently been used for classifying ME types. The aim of this study was to investigate the validity and reliability of the Slovene version of the MEQ (Slovene MEQ). Two hundred and sixty-five participants (65.3% women, 34,7% men, mean age 38,1 years, range 19–67) took the Slovene MEQ twice, 2 weeks apart (MEQ test and retest). Internal consistency of the Slovene MEQ items was high, with Cronbach’s Alpha coefficients of 0.86. The test–retest reliability was also high, with intraclass correlation coefficient (ICC) of 0.96. The classification of chronotypes on middle-aged population offered a more balanced representation of the five chronotypes than those proposed by the authors Horne and Östberg . Age changes in chronotype could be confirmed in this study in the supposed direction with older adults being more morning-oriented. The criterion validity of the Slovene MEQ through the relationship of morningness and basic personality traits showed that conscientiousness and agreeableness demonstrated positive and significant correlations with morningness. A low negative correlation was observed between openness and morningness, with higher eveningness among more open participants.     

Reliability and validity of the Korean version of Morningness–Eveningness Questionnaire in adults aged 20–39 years

Morningness–Eveningness (ME) can be defined by the difference in individual diurnal preference observed from general behavioral patterns including sleep habits. The Horne & Östberg Morningness–Eveningness Questionnaire (MEQ) has been used for classifying ME types. We examined the reliability of a Korean version of the MEQ (Korean MEQ) and verified its validity by comparing responses on the Korean MEQ to objectively-recorded sleep–wake rhythms. After translating and back translating the MEQ from English into Korean, we examined the internal consistency of 19 items of the Korean MEQ in 91 subjects, and the test–retest reliability in 21 subjects who took the Korean MEQ twice, 4 weeks apart. The Korean MEQ was then administered to 1022 young adult subjects. A subset of 46 morning, neither, and evening type subjects took part in a validation study in which their rest-activity timing was collected by actigraphy for 7 days. Cosinor analyses on these data were done to obtain the acrophase and amplitude of the sleep–wake rhythm. Cronbach’s alpha of the total scores from the Korean MEQ was 0.77, and the test–retest reliability intra-class correlation coefficient was 0.90 (p?<?0.0001). There was a significant negative correlation between Korean MEQ score and reported sleep–wake timing among the entire cohort (p?<?0.0001). There was a significant difference in bedtime and wake time (on both work and free days), and in the mean sleep–wake rhythm acrophase, between ME types (p?<?0.01). In this study, the validity of the Korean MEQ was verified by illustrating the difference in acrophases of the sleep–wake rhythm between the ME types in young adults.