Medication status of participants in psychopathology research: selective review of current reporting practices.

The majority of Ss included in studies of psychopathology are typically receiving psychoactive medication. In view of concerns regarding the confounding effects of psychoactive medication, it appears that researchers should provide information regarding at least the drug status of the Ss studied. A review of the articles on adult psychopathology that appeared in the Journal of Abnormal Psychology during a 5-year period, however, revealed that nearly 50% of reports on Ss presumably receiving psychoactive medications failed to specify the medication status of those Ss. Few studies (15%) provided adequate information regarding the types and dosages of psychoactive drugs received by the Ss. It is argued that researchers should provide a full report of the psychoactive drugs received by research participants and, when participants are unmedicated, to indicate the reasons for drug-free status.     

Some properties of the olfactory system of man

Preliminary investigations into the effects of a 12-h diurnal variation suggested there was a 10-fold decrease in odor sensitivity from morning to evening. For a selected group of odorants (methyl, t-butyl, and phenyl isonitrile), the difference between detection and recognition thresholds in general was found to be 10-fold; however, for some Ss the difference was less. When Ss were blindfolded, no changes in odor sensitivity were noted. Similarly, imposing an auditory stress on the test situation did not significantly alter odor sensitivity in either experienced or naive Ss,     

Culture and the organization of infant sleep: A study in the Netherlands and the U.S.A.

This study investigates differences in the amount and structure of infant sleep in two cultural places with previously documented, divergent parental beliefs and practices. Eight-month-old infants (n = 24 per site) were recruited from towns in the Netherlands and the eastern U.S.A. To evaluate sleep, infants’ physical activity was recorded at home for 24 h using a miniature actigraph, while parents kept a diary of infant activities. Measures derived from actigraphy include total sleep, longest sleep episode, longest wake episode, number of sleep episodes, and percent of sleep during nighttime, as well as time in the stages of Quiet and Active Sleep. Measures based on the parental diaries include most of these aspects as well, except those related to sleep stages. Results based on the more precise actigraphy method indicate that (1) the Dutch infants averaged 13.65 h of sleep per 24 h, 1.67 h more than the U.S. infants; this difference was mostly due to daytime sleep; (2) The Dutch infants’ longest wake episode averaged less than that of the U.S. infants, while their longest sleep episode appeared slightly longer. (3) The Dutch infants, compared to the U.S. sample, spent more time in the Quiet, rather than the Active phase of sleep; (4) They began their Quiet sleep earlier in the evening than did their U.S. counterparts. Measures derived from parental diaries are largely in agreement with the actigraph findings. These results are consistent with reported and observed practices and beliefs in the two communities. The pattern of differences – less apparent maturity among the Dutch in the amount of sleep, but greater apparent maturity in the structure of sleep -- illustrates that behavioral and neurological maturity can be assessed only in the context of the developing child’s adaptation to the specific demands and affordances of the culturally structured developmental niche.     

Forgetting as a function of sleep at different times of day

The experiment studied the separate effects of sleep and time period of retention interval on forgetting. A free recall task was given to independent groups of subjects either at night or in the morning, and a second recall demanded 5 h later, after an intervening period of sleeping or waking activity. Oral body temperatures (BT) were measured at each session. The data were analysed in terms of (a) immediate recall at test 1, and (b) amount forgotten from test 1 to test 2. Immediate recall was higher for morning groups, in agreement with previous findings, serial position analysis indicating that the effect is confined to enhancement of the primary memory component. Long-term retention was higher over the night interval, irrespective of sleeping conditions, though having slept at night produced better retention than having stayed awake. Sleep during the morning was not effective in reducing forgetting. BT showed a marked drop for both night groups and rise for day groups over the retention interval. Alternative explanations for the classical sleep/memory findings are suggested in terms of (a) differential effects of sleep stages on memory, and (b) the underlying diurnal variation in BT and other processes.     

Sleep among presentations of Attention-Deficit/Hyperactivity Disorder: Analysis of objective and subjective measures

Background/ObjectiveTo examine subjective and objective sleep patterns in children with different Attention-Deficit/Hyperactivity Disorder (ADHD) presentations. Method: We assessed 92 children diagnosed with ADHD (29 ADHD-Inattentive [ADHD-I], 31 ADHD-Hyperactive/Impulsive [ADHD-H/I], and 32 ADHD-Combined [ADHD-C)]) aged 7–11 years. The Pediatric Sleep Questionnaire (PSQ), Pediatric Daytime Sleepiness Scale (PDSS), and a sleep diary were used as subjective sleep measures, and polysomnography was used to objectively assess sleep quantity, quality, and fragmentation. Results: Subjective data showed impaired sleep in 12.7% of the sample. No significant differences were found between ADHD presentations in any objective and subjective sleep variable. Nevertheless, data on sleep fragmentation suggested a worse sleep continuity for the ADHD-H/I group, and correlation analyses confirmed that sleep is affected by age. Conclusions: Children with ADHD may suffer from sleep breathing problems and daytime sleepiness, as reported by their parents, even when their total sleep time and sleep efficiency are not affected. It seems that sleep in this population does not largely vary as a function of the ADHD presentation. Sleep in children with ADHD evolves with age.     

Sleep duration and chronotype in adults in Côte d'Ivoire: influence of gender,religion and age

This study investigated the sleep-wake rhythm and chronotype of people living in Côte d'Ivoire. We assessed sleep-wake behaviour in 556 adults (336 men, 220 women) between 25 and 54 years (mean: 38.63) by means of structured interviews. Data were analysed by linear models with sleep wake variables as dependent variables and age, gender, religion and region (urban/rural) as fixed factors controlling for number of working hours and children. Results suggest sleep length not to differ between weekdays and weekends but sleep timing (chronotype) was later on weekends with a midpoint of sleep at 1:37am during weekdays compared to 1:58am on weekends. The more children, the earlier was the midpoint of sleep and the shorter was sleep length. Midpoint of sleep was earlier in older people. Women slept longer during weekdays and were earlier chronotypes. Sleep duration was longer in the rural areas and midpoint of sleep was later in the urban areas on weekdays and on the weekend. Muslims showed the shortest sleep duration and were earliest chronotypes. Sleep-wake cycles in the African setting sample were shorter for women, Moslems, and older people.     

Sleep after learning aids memory recall

In recent years, the effect of sleep on memory consolidation has received considerable attention. In humans, these studies concentrated mainly on procedural types of memory, which are considered to be hippocampus-independent. Here, we show that sleep also has a persisting effect on hippocampus-dependent declarative memory. In two experiments, we examined high school students' ability to remember vocabulary. We show that declarative memory is enhanced when sleep follows within a few hours of learning, independent of time of day, and with equal amounts of interference during retention intervals. Sleep deprivation has a detrimental effect on memory, which was significant after a night of recovery sleep. Thus, fatigue accumulating during wake intervals could be ruled out as a confound.     

Nap‐dependent learning in infants

Sleep has been shown to aid a variety of learning and memory processes in adults ( Stickgold, 2005 ). Recently, we showed that infants’ learning also benefits from subsequent sleep such that infants who nap are able to abstract the general grammatical pattern of a briefly presented artificial language ( Gomez, Bootzin & Nadel, 2006 ). In the present study, we demonstrate, for the first time, long‐term effects of sleep on memory for an artificial language. Fifteen‐month‐old infants who had napped within 4 hours of language exposure remembered the general grammatical pattern of the language 24 hours later. In contrast, infants who had not napped shortly after being familiarized with the language showed no evidence of remembering anything about the language. Our findings support the view that infants’ frequent napping plays an essential role in establishing long‐term memory.     

Circadian typology and the Alternative Five‐Factor Model of personality

Two studies were carried out to explore the relationship between circadian typology and the Alternative Five‐Factor Model of personality. In the first study, 379 participants (232 females) were administered the reduced version of the Morningness‐Eveningness Questionnaire and the Zuckerman–Kuhlman Personality Questionnaire. Evening types reported higher impulsive sensation‐seeking scores than morning and intermediate types, whereas morning types scored higher than evening types on activity factor. In the second study, the association between morningness and activity personality factor was verified through the objective‐actigraphic monitoring of the rest‐activity cycle. Actigraphy allowed us to operationalise both circadian typology, through the computing of midpoint of sleep (early values, expressed in hours and minutes, correspond to an advanced phase of the sleep/wake cycle), and activity factor by the means of motor activity recording. Fifty‐one individuals (30 females) wore an actigraph on the nondominant wrist continuously for 1 week. A negative correlation was observed between midpoint of sleep and mean diurnal motor activity, demonstrating that an early phase of the sleep/wake cycle (i.e. morningness preference) was related to higher diurnal motor activity. Assessed both subjectively and objectively, the results of both studies highlight a significant relationship between morningness and activity personality factor.     

睡眠研究若干现代理论问题

最近十年间睡眠研究日益引起全世界的重视,除我国等纷纷建立“睡眠研究会”外,并新 建“亚洲睡眠研究会”和“世界睡眠研究联合会”。本文探讨睡眠研究的若干现代理论问题,其 中包括睡眠的核心是深度慢波睡眠问题,睡眠如何受制于“２４－ｈ昼夜节律”,异相睡眠和觉醒 的比较分析,世界范围内重新评价午睡的重要性,临床睡眠疾患及其对策和介诏内源性促眠物质等。     

One-trial-a-day avoidance learning

A one-trial-a-day discrete-trial avoidance conditioning procedure run for 30 consecutive days was compared with a massed-trial procedure where Ss received 30 consecutive trials within 1 day. The Ss in both groups were equated for time each S spent in the nonshock compartment of the apparatus, number of times the transport box carrying Ss was lifted out of the nonshock compartment, and the number of times each S was handled. The main difference between groups was the intersession trial length of 24 h for the one-trial-a-day Ss. Learning was rapid for both groups. The groups did not differ reliably on six acquisition indices. The methodological advantages of the one-trial-a-day procedure and its theoretical importance were discussed.     

Agreement rates for sleep/wake judgments obtained via accelerometer and sleep diary: A comparison

Agreement rates for waking and sleeping obtained via sleep diary and accelerometer were evaluated, to compare the two methods. Sleep/wake data for consecutive days and nights were surveyed in 119 healthy university students. Accelerometer sleep/wake judgments obeyed the standard algorithm. Agreement rates for waking and sleeping according to accelerometer versus sleep diary, respectively, were calculated. Sleep diary data were set as a baseline. Seventy-six subjects (63.9%), 22 to 32 years of age, presented perfect data for the analysis. The mean sleep times, in minutes, judged by sleep diary and by accelerometer, were 482.3 and 629.6, respectively. The mean percentages and standard deviations of agreement on wake and sleep were 77.5% (SD=10.2) and 86.1% (SD=6.2), respectively. There was a significant negative relationship between the agreement rates for wake and sleep (r=−.482, p<.01). The accelerometer showed some measurement failure during waking, presumably because of the decrease in body movement. Sleep diary data during daytime appear to be more valid for detecting a sleep/wake cycle than are accelerometer data. In contrast, nocturnal sleep diary data might be supplemented by the use of an accelerometer as long as participants do not have insomnia.     

Effectiveness of an mHealth Intervention for Infant Sleep Disturbances

Bedtime problems and night wakings are highly prevalent in infants. This study assessed the real-world effectiveness of an mHealth behavioral sleep intervention (Customized Sleep Profile; CSP). Caregivers (83.9% mothers) of 404 infants (age 6 to 11.9 m, M = 8.32 m, 51.2% male) used the CSP (free and publicly available behavioral sleep intervention delivered via smartphone application, Johnson’s® Bedtime® Baby Sleep App). Caregivers completed the Brief Infant Sleep Questionnaire–Revised (BISQ-R) at baseline and again 4 to 28 days later. Changes in sleep patterns were analyzed, based on sleep problem status (problem versus no problem sleepers; PS; NPS). Sleep onset latency improved in both groups. Earlier bedtimes, longer continuous stretches of sleep, as well as decreased number and duration of night wakings, were evident in the PS group only. The BISQ-R Total score, total nighttime sleep, and total 24-hour sleep time improved for both groups, with a greater change for the PS group. Further, caregivers of infants in the PS group decreased feeding (bedtime and overnight) and picking up overnight, and perceived better sleep. Bedtime routine regularity, bedtime difficulty, sleep onset difficulty, and caregiver confidence improved for both groups, with the PS group showing a greater magnitude of change. Thus, a real-world, publicly available, mHealth behavioral sleep intervention was associated with improved outcomes for older infants. Intervention recommendations resulted in changes in caregivers’ behavior and improvements in caregiver-reported sleep outcomes in infants, in as few as 4 days.     

The utility of the Pittsburgh Sleep Quality Index in US military personnel

Sleep disturbances are endemic in military personnel with nonclinical populations averaging 6 hours of sleep. The Pittsburgh Sleep Quality Index (PSQI), however, has not been validated in this population. It is thus unknown if the PSQI can differentiate clinically significant sleep disorders from sleep disturbances resulting from military duties with restricted sleep periods. After a clinical evaluation and polysomnogram, participants (N = 148) were classified as having insomnia only, obstructive sleep apnea (OSA) only, comorbid insomnia and OSA (CIO), service-related illnesses only (SRI–; pain, depression, posttraumatic stress disorder, traumatic brain injury), and controls. Military personnel in the insomnia only, and the CIO groups had higher PSQI scores (13.5 ± 2.8 and 14.7 ± 3.5, respectively) compared to the controls (8.9 ± 3.9). A cut-off score of ≥10 was optimal (90% sensitivity and 69% specificity) for determining clinically significant insomnia (≥12 for CIO; 84% sensitivity, 77% specificity). In military personnel, a PSQI score >5 is not necessarily indicative of a clinically significant sleep disorder. The use of elevated cut-off PSQI scores are likely better suited to differentiate military personnel who require further clinical evaluation versus a more conservative sleep improvement protocol.     

Exploring Socioeconomic Differences in Bedtime Behaviours and Sleep Duration in English Preschool Children

Children's sleep is critical for optimal health and development; yet sleep duration has decreased in recent decades, and many children do not have adequate sleep. Certain sleep behaviours (‘sleep hygiene’) are commonly recommended, and there is some evidence that they are associated with longer nighttime sleep. Parents of 84 British 3‐year‐old children were interviewed about their children's sleep and completed five‐night/four‐day sleep diaries documenting their children's sleep, from which daily sleep duration was estimated. Diaries were validated by actigraphy in a subgroup of children. Sleep hygiene behaviours (regular bedtime, reading at bedtime, falling asleep in bed) were associated with each other, and were more common in the high socioeconomic status compared to the low socioeconomic status group. Parents' reasons for not practicing sleep hygiene included difficulty, inability or inconvenience. Sleep hygiene behaviours were associated with significantly longer child sleep at night but not over 24 h. Longer daytime napping compensated for shorter nighttime sleep in children whose parents did not implement sleep hygiene behaviours. Parents may need to be advised that certain behaviours are associated with longer nighttime sleep and given practical advice on how to implement these behaviours. © 2014 The Authors. Infant and Child Development published by John Wiley & Sons, Ltd.     

Anxiety sensitivity and daily cigarette smoking in relation to sleep disturbances in treatment-seeking smokers

ABSTRACT

Although the association between anxiety and sleep disturbance is well-documented, the underlying mechanisms are less clear. Anxiety sensitivity (AS), the fear of physiological arousal and bodily sensations, is a risk factor for anxiety and poor sleep. Smoking also contributes to poor sleep and may compound the effects of AS on sleep quality. This study evaluated the main and interactive effects of AS and cigarettes/day on sleep quality among smokers. Participants (n = 190) were adult treatment-seeking daily smokers who completed a baseline assessment as part of a larger smoking cessation trial. Sleep quality was self-reported. Results indicated that AS was significantly correlated with greater disturbance in sleep duration, subjective sleep quality, sleep onset latency, sleep disturbance, daytime dysfunction, and sleep medication use. There was a significant interaction between AS and cigarettes/day in terms of sleep onset latency, but not other sleep quality indices. AS was associated with significantly longer sleep onset latency minutes among heavier smokers, but not lighter smokers. Specifically, the association between AS and sleep onset latency was significant for those who smoked ≥ 33 cigarettes/day. AS is a psychological factor that may contribute to poor sleep quality, especially in heavy smokers, and thus may be a promising intervention target.     

Effects of temporal uncertainty on watchkeeping performance

Two experiments were conducted to assess the relative effects of signal density and regularity on watchkeeping performance. In Experiment I, three levels of density (6, 24, and 96 signals/hr.) were combined factorially with three levels of variability (coefficients of variation of 0.01, 0.l0, and 1.00), and I0 Ss were assigned at random to each of the nine conditions. In Experiment II, five leveIs of density (6, 12, 24, 48, and 96 signals/hr.) were combined with the same three levels of variability, and 13 Ss were assigned to each condition. Each S monitored a visual “blinking-lights” display for an hour under instructions to detect and report the occurrence of certain “critical signals,” i.e., arrests of alternation of the lights. Response times (RT’s) to correctly detected signals in both experiments decreased as a linear function of logarithmic increases in signal density. An uncertainty metric, the signal surprisal due to density, was derived, and the watchkeeper’s RT was expressed as an increasing linear function of this measure of temporal uncertainty. Interpretation of these and 0 ther data support a functional, psychophysical approach to the study of watchkeeping behavior.     

Twenty-four hours of total sleep deprivation selectively impairs attentional networks

Performance decrements after sleep loss have been extensively studied and are usually attributed to generic attentional deficits. This claim, however, is based on the view of attention as a unitary construct, despite evidence that it should be considered a multidimensional cognitive ability. The aim of the present study was to evaluate the impact of one night of sleep deprivation on the efficiency of three attentional networks, defined by Posner and Raichle (1994) in anatomical and functional terms, as alerting, orienting, and executive control. Thirty participants performed the Attention Network Test at 9:00 a.m. following two different sleep conditions: baseline (a normal night of sleep) and deprivation (24 hrs of wakefulness). Results showed an overall slowing in reaction times and a significant decrease in accuracy after sleep deprivation. Sleep deprivation selectively affected the three attentional networks, given that only executive control efficacy significantly decreased after sleep deprivation. By contrast, phasic alerting and orienting showed no differences in the two sleep conditions. Thus, performance deficits following sleep deprivation do not reflect global attentional deficits.     

Consolidation of novel word learning in native English-speaking adults

Sleep has been shown to improve the retention of newly learned words. However, most methodologies have used artificial or foreign language stimuli, with learning limited to word/novel word or word/image pairs. Such stimuli differ from many word-learning scenarios in which definition strings are learned with novel words. Thus, we examined sleep's benefit on learning new words within a native language by using very low-frequency words. Participants learned 45 low-frequency English words and, at subsequent recall, attempted to recall the words when given the corresponding definitions. Participants either learned in the morning with recall in the evening (wake group), or learned in the evening with recall the following morning (sleep group). Performance change across the delay was significantly better in the sleep than the wake group. Additionally, the Levenshtein distance, a measure of correctness of the typed word compared with the target word, became significantly worse following wake, whereas sleep protected correctness of recall. Polysomnographic data from a subsample of participants suggested that rapid eye movement (REM) sleep may be particularly important for this benefit. These results lend further support for sleep's function on semantic learning even for word/definition pairs within a native language.