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.     

Cross-Sectional Age Analysis of Sleep Problems in 2 to 17 Year Olds with ADHD Combined,ADHD Inattentive,or Autism

Sleep problems are common in autism and ADHD. No study has compared sleep problems by age in 2 to 17 year olds with autism versus ADHD-Combined versus ADHD-Inattentive type. Mothers rated 1415 youth with autism and 1041 with ADHD on 10 Pediatric Behavior Scale sleep items. Nighttime sleep problems were most severe in autism, followed by ADHD-Combined, and then ADHD-Inattentive. Difficulty falling asleep, restless during sleep, and waking during the night were the most common problems. Adolescents slept more at night than other age groups, and youth who slept more at night were sleepier during the day. Sleep problems declined with age, but correlations were small. In adolescence, 63% with autism, 53% with ADHD-Combined, and 57% with ADHD-Inattentive had difficulty falling asleep. Given that the majority of children in all age groups had one or more sleep problem, developmentally appropriate interventions are needed to address sleep difficulties and limit their adverse effects.

     

Comparison of Motionlogger Watch and Actiwatch actigraphs to polysomnography for sleep/wake estimation in healthy young adults

Sleep/wake identification and sleep parameter estimates from Motionlogger Watch and Actiwatch-64 actigraphs were compared to polysomnography (PSG). Following one night of baseline sleep, 29 volunteers remained awake for 36 h, followed by 11 h of recovery sleep in the laboratory. Two sets of analyses were performed: (1) epoch-by-epoch agreement and discriminability index (d') calculations, and (2) sleep parameter concordance with repeated measures ANOVAs. Sensitivity (sleep identification), specificity (wake detection), and overall agreement with PSG, as well as d', were higher for the Motionlogger than for Actiwatch. Relative to PSG, the Actiwatch-estimated total sleep time and sleep efficiency were underestimated and the number of awakenings was overestimated for baseline and recovery; sleep latency was underestimated on the baseline night. On the other hand, the Motionlogger-estimated total sleep time and sleep efficiency estimates were underestimated, and the sleep latency was overestimated on recovery, versus PSG. Despite these misestimations, it was concluded that the Motionlogger provided nominally better agreement with PSG, and that actigraphy generally constitutes a reasonably reliable tool for producing objective measurements of sleep/wake, but that users should remain mindful of its limitations.     

Cognitive empathy modulates the visual perception of human-like body postures without imitation

To examine the mechanism of visual perception of human-like body postures, we conducted a posture recognition task, a questionnaire survey, and the Interpersonal Reactivity Index (IRI). The majority of participants perceived the pseudo-posture as a human posture in the early stage (78%), but only approximately half of them reported the imagination of bodily movement (66%). These results suggest that the majority of observers perceive pseudo-postures as human postures in the early stage of perception, but this human posture perception does not necessarily lead to the visualisation of bodily movement. In a group of who received the pseudo posture as a human-posture regardless of the perception stages, the participants who imagined bodily movement (64%) showed significantly higher scores than those who did not on the Fantasy subscale of the IRI. Highly empathic participants are more likely to detect a kinematic relation between the pseudo-postures.     

Posttraining increases in REM sleep intensity implicate REM sleep in memory processing and provide a biological marker of learning potential

Posttraining rapid eye movement (REM) sleep has been reported to be important for efficient memory consolidation. The present results demonstrate increases in the intensity of REM sleep during the night of sleep following cognitive procedural/implicit task acquisition. These REM increases manifest as increases in total number of rapid eye movements (REMs) and REM densities, whereas the actual time spent in REM sleep did not change. Further, the participants with the higher intelligence (IQ) scores showed superior task acquisition scores as well as larger posttraining increases in number of REMs and REM density. No other sleep state changes were observed. None of the pretraining baseline measures of REM sleep were correlated with either measured IQ or task performance. Posttraining increases in REM sleep intensity implicate REM sleep mechanisms in further off-line memory processing, and provide a biological marker of learning potential.     

Recognition of dance-like actions: Memory for static posture or dynamic movement?

Dance-like actions are complex visual stimuli involving multiple changes in body posture across time and space. Visual perception research has demonstrated a difference between the processing of dynamic body movement and the processing of static body posture. Yet, it is unclear whether this processing dissociation continues during the retention of body movement and body form in visual working memory (VWM). When observing a dance-like action, it is likely that static snapshot images of body posture will be retained alongside dynamic images of the complete motion. Therefore, we hypothesized that, as in perception, posture and movement would differ in VWM. Additionally, if body posture and body movement are separable in VWM, as form- and motion-based items, respectively, then differential interference from intervening form and motion tasks should occur during recognition. In two experiments, we examined these hypotheses. In Experiment 1, the recognition of postures and movements was tested in conditions in which the formats of the study and test stimuli matched (movement–study to movement–test, posture–study to posture–test) or mismatched (movement–study to posture–test, posture–study to movement–test). In Experiment 2, the recognition of postures and movements was compared after intervening form and motion tasks. These results indicated that (1) the recognition of body movement based only on posture is possible, but it is significantly poorer than recognition based on the entire movement stimulus, and (2) form-based interference does not impair memory for movements, although motion-based interference does. We concluded that, whereas static posture information is encoded during the observation of dance-like actions, body movement and body posture differ in VWM.     

Sleep duration and self-reported Type A behavior: a replication.

Scores on the Jenkins Activity Survey (Form T)(Glass, 1977) were compared for 58 and 70 university students who reported, respectively, a regular sleep pattern of less or more than 8 hr per night. Replicating a previous report (Hicks et al., 1979), subjects who slept fewer hours scored higher on Type A behavior questions than those who slept more hours. However, for subjects with a less stable sleeping pattern, Type A scores for the two groups (ns = 72, 23) did not differ.     

Postural sway and joint kinematics during quiet standing are affected by lumbar extensor fatigue

The purpose of this study was to investigate changes in postural sway and strategy elicited by lumbar extensor muscle fatigue. Specifically, changes in center of mass (COM), center of pressure (COP), and joint kinematics during quiet standing were determined, as well as selected cross correlations between these variables that are indicative of movement strategy. Twelve healthy male participants stood quietly both before and after exercises that fatigued the lumbar extensors. Whole-body movement and ground reaction force data were recorded and used to calculate mean body posture and variability of COM, COP, and joint kinematics during quiet standing. Three main findings emerged. First, participants adopted a slight forward lean post-fatigue as evidenced by an anterior shift of the COM and COP. Second, post-fatigue increases in joint angle variability were observed at multiple joints including joints distal to the fatigued musculature. Despite these increases, anterior-posterior (AP) ankle angle correlated well with AP COM position, suggesting the body still behaved similar to an inverted pendulum. Third, global measures of sway based on COM and COP were not necessarily indicative of changes in individual joint kinematics. Thus, in trying to advance our understanding of how localized fatigue affects movement patterns and the postural control system, it appears that joint kinematics and/or multivariate measures of postural sway are necessary.     

Using a Behavioral Treatment Package for Sleep Problems in Children With Autism Spectrum Disorders

This study investigated the effectiveness of a behavioral treatment package for sleep problems in children diagnosed with Autism Spectrum Disorders. Treatment consisted of four behaviorally based components: circadian rhythm management, positive bedtime routines, white noise, and graduated extinction. A multiple-baseline design across three participants was used. Families completed a baseline of various lengths followed by 1 month of intervention. Results indicated the treatment package was effective in decreasing sleep onset latency and the frequency of night awakenings. A week of follow-up data showed continued improvement. Parents reported their children slept better and satisfaction with the four intervention components.     

The effect of subliminal priming on sleep duration

Two experiments primed college students with either sleep‐related or neutral words and then assessed sleep during a 25 minute nap period. Both experiments showed that participants primed with sleep‐related words reported having slept longer than did those primed with neutral words. Furthermore, both experiments showed that sleep‐primed participants exhibited lower heart rate. Experiment 2 also revealed that the effect of the priming manipulation was especially strong among participants who had trouble sleeping. This suggests that priming might be a cost‐effective treatment for inducing sleep among people with sleep problems.     

Nighttime sleep and physical activity in 6-7 month-old infants

This study examined associations between objectively-measured nighttime sleep duration and physical activity in a sample of 6–7 month-old infants (N=93). The study also investigated relationships between infant sleep and demographic and environmental characteristics. Cross-sectional relationships were assessed using linear regression analyses. Nighttime sleep duration was positively associated with physical activity levels. Nighttime sleep duration was greater when infants had a consistent bedtime, slept in a separate room, were male, and had mothers who reported having a college education or greater. These findings can inform the development of interventions that aim to improve infant sleep.     

Sleep arrangements and maternal adaptation in infancy

Among the many decisions that parents make regarding child‐rearing practices, an important one involves sleep arrangements. Little is known about the relationship between chosen sleep arrangements, parents' adaptation to these choices, parental sleep quality, spousal support, and parental distress. Forty‐five mothers and fathers with infants 1 to 24 months old completed measures of parental attitudes and practices regarding sleep arrangements. Shared sleep with one's infant was associated with poorer parental adaptation to infant sleep disruption, and this was true even when parents endorsed the practice of sharing sleep with their infants. Among mothers, shared sleep and poorer adaptation to infant sleep were significantly associated with elevated depressive symptoms, poorer sleep quality, and spousal criticism directed to mothers about where the infant slept during the night. For mothers, criticism from their spouses about where the baby slept, mothers' sleep quality, and depressive symptoms mediated the link between sleep arrangements and maternal adaptation. Results emphasize the importance of taking into account individual differences in the quality of parents' adaptation to infant sleep behavior, a construct largely ignored in the child sleep literature to date, in understanding linkages between infant sleep quality and infant–parent outcomes.     

Body Posture and the Feeling of Social Closeness: An Exploratory Study in a Naturalistic Setting

Previous research has shown that body postures and body movements influence people’s attitudes, preferences and feelings. In the present study, we explored the influence of body posture on the feeling of closeness towards others and how this effect may interact with contextual variables. Study 1 was conducted in a naturalistic setting in which 127 participants observed a series of live dance sequences either standing up or remaining seated. After each sequence, participants reported the feelings elicited by the dance performance on a questionnaire. Visibility of performers’ facial expressions and background tempo were used as contextual variables. Results showed that participants who watched the performance standing up felt significantly closer to the dancers than participants who remained seated. Study 2 was carried out in a laboratory setting to explore the relationship between body posture, tempo and heart rate. Results showed a significant increase in heart rate when standing compared to when sitting and no effect of tempo. The present research demonstrates a link between body posture and social connection providing evidence that standing up strengthens the feeling of closeness to others, and showing that posture not only has an impact on self-related feelings (e.g. fear, anger, sadness) as previous research has shown, but also has an impact on feelings towards others at the base of all human social relations. The present research also suggests that heart rate may be a mediator of the effect of posture on the feeling of closeness.     

The impact of post-learning sleep vs. wakefulness on recognition memory for faces with different facial expressions

A beneficial effect of sleep after learning, compared to wakefulness, on memory formation has been shown in many studies using a variety of tasks. However, none of these studies has specifically addressed recognition memory for faces so far. The recognition of familiar faces, together with the extraction of emotional information from facial expression, is a fundamental cognitive skill in human everyday life, for which specific neural systems and mechanisms of processing have been developed. Here, we investigated the role of post-learning sleep for later recognition memory for neutral, happy, and angry faces. Twelve healthy subjects, after judging the emotional valence of the faces in the evening (learning phase), either slept normally in the subsequent night, with sleep recorded polysomnographically (sleep condition), or remained awake (wake condition) according to a cross-over design. Recognition testing took place in the second evening after learning, i.e. after a further night of regular sleep spent at home. Sleep after learning, compared to wakefulness, enhanced memory accuracy in recognition memory. This effect was independent of the emotional valence of facial expression. The response criterion at recognition testing did not differ between sleep and wake conditions. The amount of non rapid eye movement (NonREM) sleep during post-learning sleep correlated positively with memory accuracy at recognition testing, while time in REM sleep was associated with a speeded responding to the learned faces. Results suggest that face recognition, despite its dependence on specialized brain systems, nevertheless relies on the general neural mechanisms of sleep-associated memory consolidation.     

Attention and movement execution during handwriting

Two studies were performed in order to test the hypothesis that movement execution during handwriting in skilled writers is independent of attention. Study I examined the relationship between attentional functioning and kinematic aspects of handwriting movements in 24 adult participants. A digitizing tablet was used for the assessment of handwriting movements. Participants were asked to perform a simple writing task and various components of their attention were assessed. Correlation analysis indicated no significant relationship between attention functions and both kinematic aspects of handwriting movements and quality of handwriting. In Study II, 20 participants underwent total sleep deprivation (TSD) for 24h. While attention, as assessed with alertness and vigilance tasks, deteriorated during TSD, the execution of handwriting movements, as assessed with a digitizing tablet, improved markedly. The quality of handwriting was not affected by TSD. These findings may suggest an independence between attention and movement generation during handwriting.     

Hemispheric lateralization of the EEG during wakefulness and REM sleep in young healthy adults

EEG recordings confirm hemispheric lateralization of brain activity during cognitive tasks. The aim of the present study was to investigate spontaneous EEG lateralization under two conditions, waking and REM sleep. Bilateral monopolar EEG was recorded in eight participants using a 12-electrode montage, before the night (5 min eyes closed) and during REM sleep. Spectral analysis (0.75-19.75 Hz) revealed left prefrontal lateralization on total spectrum amplitude power and right occipital lateralization in Delta activity during waking. In contrast, during REM sleep, right frontal lateralization in Theta and Beta activities and right lateralization in occipital Delta activity was observed. These results suggest that spontaneous EEG activities generated during waking and REM sleep are supported in part by a common thalamo-cortical neural network (right occipital Delta dominance) while additional, possibly neuro-cognitive factors modulate waking left prefrontal dominance and REM sleep right frontal dominance.     

Laterality of repetitive finger movement performance and clinical features of Parkinson’s disease

Impairments in acoustically cued repetitive finger movement often emerge at rates near to and above 2 Hz in persons with Parkinson’s Disease (PD) in which some patients move faster (hastening) and others move slower (bradykinetic). The clinical features impacting this differential performance of repetitive finger movement remain unknown. The purpose of this study was to compare repetitive finger movement performance between the more and less affected side, and the difference in clinical ratings among performance groups. Forty-one participants diagnosed with idiopathic PD completed an acoustically cued repetitive finger movement task while “on” medication. Eighteen participants moved faster, 10 moved slower, and 13 were able to maintain the appropriate rate at rates above 2 Hz. Clinical measures of laterality, disease severity, and the UPDRS were obtained. There were no significant differences between the more and less affected sides regardless of performance group. Comparison of disease severity, tremor, and rigidity among performance groups revealed no significant differences. Comparison of posture and postural instability scores revealed that the participants that demonstrated hastening had worse posture and postural instability scores. Consideration of movement rate during the clinical evaluation of repetitive finger movement may provide additional insight into varying disease features in persons with PD.     

Reversible Verbal Memory Integration Deficits in Obstructive Sleep Apnoea

When presented with novel but semantically related elements after learning verbal material, healthy participants tend to endorse these items as previously learned. This reflects the normal integration and association of novel verbal information into long-term memory. How obstructive sleep apnoea (OSA) negatively impacts verbal memory performance, and whether deficits are reversible following positive airway pressure (PAP) treatment, remain elusive. We investigated immediate and delayed OSA- and PAP treatment-related effects on verbal memory integration, using a false memory paradigm. Twenty-three patients with OSA learned lists of words semantically related to target non-presented words (1) at baseline after a polysomnography diagnosis night, (2) after a consecutive polysomnography night under PAP titration, and (3) after three months of compliant PAP treatment. At each session, participants learned 10 different lists of words, each list comprising 15 semantically related items. They had then to recognize 15 minutes later (after an intermediate vigilance task) previously learned words within a list including studied words (learned), unstudied but semantically related items (lures), and non-related unstudied items (controls). Sleep quality and fatigue questionnaires, and psychomotor vigilance tests (PVT) were administered at each session. PAP treatment led to OSA remission and improvement in objective and subjective sleep quality. Crucially, recognition of learned and lure words increased after the first night under treatment and remained stable three months later, suggesting successful memory integration and restoration of semantic processes. No treatment-related outcome was found on PVT performance. OSA exerts a detrimental but PAP-reversible effect on verbal learning and semantic memory integration mechanisms underlying the acquisition of novel memory representations.     

Are changes in beliefs and attitudes about sleep related to sleep improvements in the treatment of insomnia?

Dysfunctional beliefs and attitudes about sleep are presumed to play an important mediating role in perpetuating insomnia. The present study evaluated the impact of cognitive-behavioral and pharmacological treatments for insomnia on sleep-related beliefs and attitudes and the relationship between those changes and sleep improvements. The participants were older adults with chronic and primary insomnia. They received cognitive-behavior therapy (CBT), pharmacotherapy (PCT), combined CBT+PCT (COMB), or a medication placebo (PLA). In addition to daily sleep diaries and sleep laboratory measures, the participants completed the dysfunctional beliefs and attitudes about sleep scale (DBAS) at baseline and posttreatment, and at 3-, 12- and 24-month follow-up assessments. The results showed that CBT and COMB treatments produced greater improvements of beliefs and attitudes about sleep at posttreatment than PCT and PLA. Reductions of DBAS scores were significantly correlated with improvements of sleep efficiency as measured by daily sleep diaries and by polysomnography. In addition, more adaptive beliefs and attitudes about sleep at posttreatment were associated with better maintenance of sleep improvements at follow-ups. These findings highlight the importance of targeting sleep-related beliefs and attitudes in the treatment of insomnia.     

Neck posture is influenced by anticipation of stepping

BackgroundPostural deviations such as forward head posture (FHP) are associated with adverse health effects. The causes of these deviations are poorly understood. We hypothesized that anticipating target-directed movement could cause the head to get “ahead of” the body, interfering with optimal head/neck posture, and that the effect may be exacerbated by task difficulty and/or poor inhibitory control.MethodWe assessed posture in 45 healthy young adults standing quietly and when they anticipated walking to place a tray: in a simple condition and in conditions requiring that they bend low or balance an object on the tray. We defined FHP as neck angle relative to torso; we also measured head angle relative to neck and total neck length. We assessed inhibitory control using a Go/No-Go task, Stroop task, and Mindful Attention Awareness Scale (MAAS).ResultsFHP increased when participants anticipated movement, particularly for more difficult movements. Worse Stroop performance and lower MAAS scores correlated with higher FHP. False alarms on the Go/No-Go task correlated with a more extended head relative to the neck and with shortening of the neck when anticipating movement.ConclusionsMaintaining neutral posture may require inhibition of an impulse to put the head forward of the body when anticipating target-directed movement.