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Sleep reactivation did not boost suppression-induced forgetting.
Schechtman, E, Lampe, A, Wilson, BJ, Kwon, E, Anderson, MC, Paller, KA
Scientific reports. 2021;(1):1383
Abstract
Sleep's role in memory consolidation is widely acknowledged, but its role in weakening memories is still debated. Memory weakening is evolutionary beneficial and makes an integral contribution to cognition. We sought evidence on whether sleep-based memory reactivation can facilitate memory suppression. Participants learned pairs of associable words (e.g., DIET-CREAM) and were then exposed to hint words (e.g., DIET) and instructed to either recall ("think") or suppress ("no-think") the corresponding target words (e.g., CREAM). As expected, suppression impaired retention when tested immediately after a 90-min nap. To test if reactivation could selectively enhance memory suppression during sleep, we unobtrusively presented one of two sounds conveying suppression instructions during sleep, followed by hint words. Results showed that targeted memory reactivation did not enhance suppression-induced forgetting. Although not predicted, post-hoc analyses revealed that sleep cues strengthened memory, but only for suppressed pairs that were weakly encoded before sleep. The results leave open the question of whether memory suppression can be augmented during sleep, but suggest strategies for future studies manipulating memory suppression during sleep. Additionally, our findings support the notion that sleep reactivation is particularly beneficial for weakly encoded information, which may be prioritized for consolidation.
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Early Morning Food Intake as a Risk Factor for Metabolic Dysregulation.
Stothard, ER, Ritchie, HK, Birks, BR, Eckel, RH, Higgins, J, Melanson, EL, Wright, KP, McHill, AW
Nutrients. 2020;(3)
Abstract
Increased risk of obesity and diabetes in shift workers may be related to food intake at adverse circadian times. Early morning shiftwork represents the largest proportion of shift workers in the United States, yet little is known about the impact of food intake in the early morning on metabolism. Eighteen participants (9 female) completed a counterbalanced 16 day design with two conditions separated by ~1 week: 8 h sleep opportunity at habitual time and simulated early morning shiftwork with 6.5 h sleep opportunity starting ~1 h earlier than habitual time. After wake time, resting energy expenditure (REE) was measured and blood was sampled for melatonin and fasting glucose and insulin. Following breakfast, post-prandial blood samples were collected every 40 min for 2 h and the thermic effect of food (TEF) was assessed for 3.25 h. Total sleep time was decreased by ~85 min (p < 0.0001), melatonin levels were higher (p < 0.0001) and post-prandial glucose levels were higher (p < 0.05) after one day of simulated early morning shiftwork compared with habitual wake time. REE was lower after simulated early morning shiftwork; however, TEF after breakfast was similar to habitual wake time. Insufficient sleep and caloric intake during a circadian phase of high melatonin levels may contribute to metabolic dysregulation in early morning shift workers.
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The impact of anticipating a stressful task on sleep inertia when on-call.
Kovac, K, Vincent, GE, Jay, SM, Sprajcer, M, Aisbett, B, Lack, L, Ferguson, SA
Applied ergonomics. 2020;:102942
Abstract
Sleep inertia, the state of reduced alertness upon waking, can negatively impact on-call workers. Anticipation of a stressful task on sleep inertia, while on-call was investigated. Young, healthy males (n = 23) spent an adaptation, control and two counterbalanced on-call nights in the laboratory. When on-call, participants were told they would be woken to a high or low stress task. Participants were not woken during the night, instead were given a 2300-0700 sleep opportunity. Participants slept ∼7.5-h in all conditions. Upon waking, sleep inertia was quantified using the Karolinska Sleepiness Scale and Psychomotor Vigilance and Spatial Configuration Tasks, administered at 15-min intervals. Compared to control, participants felt sleepier post waking when on-call and sleepiest in the low stress compared to the high stress condition (p < .001). Spatial performance was faster when on-call compared to control (p < .001). Findings suggest that anticipating a high-stress task when on-call, does not impact sleep inertia severity.
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4.
Sleep in the completely locked-in state (CLIS) in amyotrophic lateral sclerosis.
Malekshahi, A, Chaudhary, U, Jaramillo-Gonzalez, A, Lucas Luna, A, Rana, A, Tonin, A, Birbaumer, N, Gais, S
Sleep. 2019;(12)
Abstract
Persons in the completely locked-in state (CLIS) suffering from amyotrophic lateral sclerosis (ALS) are deprived of many zeitgebers of the circadian rhythm: While cognitively intact, they are completely paralyzed, eyes mostly closed, with artificial ventilation and artificial nutrition, and social communication extremely restricted or absent. Polysomnographic recordings in eight patients in CLIS, however, revealed the presence of regular episodes of deep sleep during night time in all patients. It was also possible to distinguish an alpha-like state and a wake-like state. Classification of rapid eye movement (REM) sleep is difficult because of absent eye movements and absent muscular activity. Four out of eight patients did not show any sleep spindles. Those who have spindles also show K-complexes and thus regular phases of sleep stage 2. Thus, despite some irregularities, we found a surprisingly healthy sleep pattern in these patients.
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Post-Hoc Analyses of the Effects of Baseline Sleep Quality on SHP465 Mixed Amphetamine Salts Extended-Release Treatment Response in Adults with Attention-Deficit/Hyperactivity Disorder.
Surman, CBH, Robertson, B, Chen, J, Cortese, S
CNS drugs. 2019;(7):695-706
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Abstract
OBJECTIVE Sleep problems are common in adults with attention-deficit/hyperactivity disorder (ADHD). The presence of sleep problems at the time of presentation for ADHD treatment could impact the level of improvement in ADHD symptoms or executive function occurring with ADHD pharmacotherapy. Therefore, we examined the influence of baseline sleep quality on the effects of SHP465 mixed amphetamine salts (MAS) extended-release. METHODS Adults (18-55 years) with Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision-defined ADHD and baseline ADHD Rating Scale IV (ADHD-RS-IV) total scores ≥ 24 were randomized to once-daily SHP465 MAS (12.5-75 mg) or placebo in a 7-week, double-blind, dose-optimization study. Post-hoc analyses evaluated SHP465 MAS treatment effects on ADHD symptoms, using the ADHD-RS-IV, and executive function, using the Brown Attention-Deficit Disorder Scale (BADDS), based on baseline sleep quality as defined by Pittsburgh Sleep Quality Index (PSQI) scores [sleep quality impaired (PSQI total score > 5; PSQI component scores 2 or 3) versus not impaired (PSQI total score ≤ 5; PSQI component scores 0 or 1)]. Analyses were conducted in the intent-to-treat population. RESULTS Of 280 enrolled participants, 272 were randomized (placebo, n = 135; SHP465 MAS, n = 137). The intent-to-treat population consisted of 268 participants (placebo, n = 132; SHP465 MAS, n = 136), and 170 participants (placebo, n = 76; SHP465 MAS, n = 94) completed the study. Treatment differences nominally favored SHP465 MAS over placebo in both sleep impairment groups regarding ADHD-RS-IV total score changes (all nominal p < 0.05), except for those with impairment defined by sleep efficiency (p = 0.2696), and regarding BADDS total score changes (all nominal p < 0.05), except for those with impairment defined by sleep duration (p = 0.1332) and sleep efficiency (p = 0.8226). There were no statistically significant differences in SHP465 MAS treatment effects between sleep impairment groups. CONCLUSIONS Improvements in ADHD symptoms and executive function occurred with dose-optimized SHP465 MAS, regardless of baseline impairment in some aspects of sleep in adults with ADHD, with no significant differences observed as a function of sleep impairment. CLINICAL TRIALS REGISTRATION ClinicalTrials.gov identifier-NCT00150579.
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Pediatric perioperative measures of sleep, pain, anxiety and anesthesia emergence: A healing touch proof of concept randomized clinical trial.
James, LE, Gottschlich, MM, Nelson, JK, Cone, LC, McCall, JE
Complementary therapies in medicine. 2019;:264-269
Abstract
BACKGROUND AND PURPOSE The purpose of this study was to determine the impact of healing touch (HT) on sleep, anxiety, anesthesia emergence and pain. METHODS HT, sham HT, control with an aide (CP) and control groups without the presence of an aide (CNP), underwent polysomnography (PSG) preoperatively. The Yale Preoperative Anxiety Scale (YPAS) score was obtained preoperatively before medications were given and in the preoperative surgery area. Sedation score, anesthesia emergence score and vital signs were recorded. Pain scores were determined by the Observation Pain Assessment Scale (OPAS) postoperatively and at time of discharge. Preoperative laboratory blood was drawn for C-reactive protein (CRP), glucose, cortisol and vitamin D25 levels as indicators of stress and anxiety, and a HT satisfaction survey was given. RESULTS Thirty-nine patients consented to participate and were randomly assigned to HT (9), HT sham (12), CP (7) and CNP (11) groups. Mean patient age was 13.0 years, and no significant group differences were found for age, sex, race or patient procedure, categorized as laser, burn reconstruction and plastic surgery reconstruction. Additionally, no significant group differences were detected for any of the PSG parameters, YPAS scores, OPAS scores, medications, anesthesia emergence score, bloodwork or satisfaction survey score. CRP, glucose and cortisol levels were higher in the CNP group, suggesting that pediatric patients undergoing elective surgeries may benefit from more pre-operative support, possibly by HT. CONCLUSIONS Although no tracked parameters showed statistically significant findings, anecdotal HT benefits included enhanced relaxation and sounder sleep.
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The role of melatonin to attain electroencephalograms in children in a sub-Saharan African setting.
Ibekwe, R, Jeaven, L, Wilmshurst, JM
Seizure. 2017;:87-94
Abstract
PURPOSE Limited access to electroencephalograms (EEGs) in sub-Saharan Africa results in a high patient load attending the few neurophysiology units. The state of sleep in children improves yield and reduces artefact of EEGs. Melatonin induces "natural sleep" without the risk of airway compromise. This study evaluated the effectiveness of oral melatonin to attain electroencephalograms in South African children. METHOD Children undergoing EEG who were unable to cooperate or required sleep EEG, received oral melatonin (3mg<15kg; 6mg>15kg). A retrospective control group received chloral hydrate. Outcome measures were the proportion of children who slept, useful EEG study data, sleep latency and duration, artefacts and EEG study abnormalities. RESULTS 173 children were recruited, 88 (51%) male, median age 4 years 9 months (range 0-14 years). 87% achieved stage 2 sleep. Median sleep latency was 44.5min and duration of sleep was 25min (range 18.5-29min). Children had no post-sedation irritability, persistent drowsiness, nor any other adverse events or deferments for inter-current illnesses. Sedation with melatonin was less successful in children with developmental and behavioural problems (χ2=6.18, P=0.046), with a higher rate of artefacts (χ2=5.83, P=0.05). 33.5% (n=58) had abnormal EEG studies, which was comparable to a historical cohort sedated with chloral hydrate (45.5%) (χ2=1.22, P=1.27). Also for artefacts (79% melatonin group versus 86% chloral hydrate group) (χ2=0.63, P=0.42). CONCLUSIONS Melatonin is effective and safe in inducing sleep for EEG recording in our setting.
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Comparison of the Effect of Two Kinds of Iranian Honey and Diphenhydramine on Nocturnal Cough and the Sleep Quality in Coughing Children and Their Parents.
Ayazi, P, Mahyar, A, Yousef-Zanjani, M, Allami, A, Esmailzadehha, N, Beyhaghi, T
PloS one. 2017;(1):e0170277
Abstract
Coughing in a child induced by upper respiratory tract infections (URTIs) can be a problem, both for the child and its parents. Current studies show a lack of proven efficacy for over-the counter (OTC) medications, but promising data support the use of honey for children. The aim of this study was to compare the effects of two kinds of Iranian honey with diphenhydramine (DPH) on nocturnal pediatric coughs and the sleep quality of children and their parents. This was a clinical trial (registered in IRCT; No.: 28.20.7932, 15 October 2013). The study consisted of 87 patients. All the parents completed a standard previously validated questionnaire. The children were randomly assigned to one of three treatment groups: Group 1, Honey type 1 (Kimia Company, Iran) (n = 42), Group 2, Honey type 2 (Shahde-Golha, Iran) (n = 25), and Group 3, DPH (n = 20). Each group received double doses of the respective treatments on two successive nights. A second survey was then administered via a telephone interview in which the parents were asked the same questions. The mean scores for all aspects of coughs were significantly decreased in each group before and after the treatment. All three treatments improved the cough and sleep scores. Honey type 1 was superior to DPH in improving all aspects of coughs, except the frequency, and Honey type 2 was more effective than DPH in improving all aspects of coughs, except the sleep quality of the child. There was no significant difference between Honey type 1 and 2 in any aspects of cough relief in the present study. The results suggest that honey may provide better cough relief than DPH in children and improve the sleep quality of children and their parents.
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The Sleep/Wake Cycle is Directly Modulated by Changes in Energy Balance.
Collet, TH, van der Klaauw, AA, Henning, E, Keogh, JM, Suddaby, D, Dachi, SV, Dunbar, S, Kelway, S, Dickson, SL, Farooqi, IS, et al
Sleep. 2016;(9):1691-700
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STUDY OBJECTIVES The rise in obesity has been paralleled by a decline in sleep duration in epidemiological studies. However, the potential mechanisms linking energy balance and the sleep/wake cycle are not well understood. We aimed to examine the effects of manipulating energy balance on the sleep/wake cycle. METHODS Twelve healthy normal weight men were housed in a clinical research facility and studied at three time points: baseline, after energy balance was disrupted by 2 days of caloric restriction to 10% of energy requirements, and after energy balance was restored by 2 days of ad libitum/free feeding. Sleep architecture, duration of sleep stages, and sleep-associated respiratory parameters were measured by polysomnography. RESULTS Two days of caloric restriction significantly increased the duration of deep (stage 4) sleep (16.8% to 21.7% of total sleep time; P = 0.03); an effect which was entirely reversed upon free feeding (P = 0.01). Although the apnea-hypopnea index stayed within the reference range (< 5 events per hour), it decreased significantly from caloric restriction to free feeding (P = 0.03). Caloric restriction was associated with a marked fall in leptin (P < 0.001) and insulin levels (P = 0.002). The fall in orexin levels from baseline to caloric restriction correlated positively with duration of stage 4 sleep (Spearman rho = 0.83, P = 0.01) and negatively with the number of awakenings in caloric restriction (Spearman rho = -0.79, P = 0.01). CONCLUSIONS We demonstrate that changes in energy homeostasis directly and reversibly impact on the sleep/wake cycle. These findings provide a mechanistic framework for investigating the association between sleep duration and obesity risk.
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10.
Beneficial impact of sleep extension on fasting insulin sensitivity in adults with habitual sleep restriction.
Leproult, R, Deliens, G, Gilson, M, Peigneux, P
Sleep. 2015;(5):707-15
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STUDY OBJECTIVES A link between sleep loss and increased risk for the development of diabetes is now well recognized. The current study investigates whether sleep extension under real-life conditions is a feasible intervention with a beneficial impact on glucose metabolism in healthy adults who are chronically sleep restricted. DESIGN Intervention study. PARTICIPANTS Sixteen healthy non-obese volunteers (25 [23, 27.8] years old, 3 men). INTERVENTIONS Two weeks of habitual time in bed followed by 6 weeks during which participants were instructed to increase their time in bed by one hour per day. MEASUREMENTS AND RESULTS Continuous actigraphy monitoring and daily sleep logs during the entire study. Glucose and insulin were assayed on a single morning blood sample at the end of habitual time in bed and at the end of sleep extension. Home polysomnography was performed during one weekday of habitual time in bed and after 40 days of sleep extension. Sleep time during weekdays increased (mean actigraphic data: +44 ± 34 minutes, P < 0.0001; polysomnographic data: +49 ± 68 minutes, P = 0.014), without any significant change during weekends. Changes from habitual time in bed to the end of the intervention in total sleep time correlated with changes in glucose (r = +0.53, P = 0.041) and insulin levels (r = -0.60, P = 0.025), as well as with indices of insulin sensitivity (r = +0.76, P = 0.002). CONCLUSIONS In healthy adults who are chronically sleep restricted, a simple low cost intervention such as sleep extension is feasible and is associated with improvements in fasting insulin sensitivity.