Here our goal was to determine the magnitude of sleep-related motor skill enhancement. Performance on the finger tapping task (FTT) was evaluated after a 90 min daytime nap (n= 15) or after quiet wakefulness (n= 15). By introducing a slight modification in the formula used to calculate the offline gains we were able to refine the estimated magnitude of sleep's effect on motor skills. The raw value of improvement after a nap decreased after this correction (from ~ 15% to ~5%), but remained significantly higher than the control. These results suggest that sleep does indeed play a role in motor skill consolidation.
Keywords: Motor skills, Finger tapping task, Daytime nap
There were no validation studies on portable sleep devices under different ambient temperature, thus this study evaluated the validity of wrist Actiwatch2 (AW2) or SenseWear armband (SWA) against polysomnography (PSG) in different ambient temperatures. Nine healthy young participants (6 males, aged 23.3±4.1 y) underwent nine nights of study at ambient temperature of 17 °C, 22 °C and 29 °C in random order, after an adaptation night. They wore the AW2 and SWA while being monitored for PSG simultaneously. A linear mixed model indicated that AW2 is valid for sleep onset latency (SOL), total sleep time (TST) and sleep efficiency (SE) but significantly overestimated wake after sleep onset (WASO) at 17 °C and 22 °C. SWA is valid for WASO, TST and SE at these temperatures, but severely underestimates SOL. However, at 29 °C, SWA significantly overestimated WASO and underestimated TST and SE. Bland-Altman plots showed small biases with acceptable limits of agreement (LoA) for AW2 whereas, small biases and relatively wider LoA for most sleep variables were observed in SWA. The kappa statistic showed a moderate sleep-wake epoch agreement, with a high sensitivity but poor specificity; wake detection remains suboptimal. AW2 showed small biases for most of sleep variables at all temperature conditions, except for WASO. SWA is reliable for measures of TST, WASO and SE at 17-22 °C but not at 29 °C, and SOL approximates that of PSG only at 29 °C, thus caution is needed when monitoring sleep at different temperatures, especially in home sleep studies, in which temperature conditions are more variable.
Keywords: Actigraphy, SenseWear armband, Validation, Sleep variables, Sleep-wake epoch analysis, Bland-Altman plots
Human sleep begins in stage 1 and progresses into stages 2 and 3 of Non-Rapid-Eye-Movement (NREM) sleep. These stages were defined using several arbitrarily-defined thresholds for subdivision of albeit continuous process of sleep deepening. Since recent studies indicate that stage 3 (slow wave sleep) has unique vital functions, more accurate measurement of this stage duration and continuity might be required for both research and practical purposes. However, the true neurophysiological boundary between stages 2 and 3 remains unknown. In a search for non-arbitrary threshold criteria for distinguishing the boundaries between NREM sleep stages, scores on the principal components of the electroencephalographic (EEG) spectrum were analyzed in relation to stage onsets. Eighteen young men made 12-20-minute attempts to nap during 24-hour wakefulness. Single-minute intervals of the nap EEG records were assigned relative to the minute of onsets of polysomnographically determined stages 1, 2, and 3. The analysis of within-nap time courses of principal components scores revealed that, unlike any conventional spectral EEG index, score on the 4th principal component exhibited a rather rapid rise on the boundary between stages 2 and 3. This was mostly a change from negative to positive score. Therefore, it might serve as yes-or-no criterion of stage 3 onset. Additionally, similarly rapid changes in sign of scores were exhibited by the 1st and 2nd principal components on the boundary of stages 2 and 1 and on the boundary between stage 1 and wakefulness, respectively.
Keywords: EEG spectrum, Principal component analysis, Slow wave sleep, Sleep scoring, Sleep-wake regulation
Intraindividual variability is an often understudied aspect of health outcomes research that may provide additional, complementary information to average values. The current paper aims to further our understanding of intraindividual variability in health research by presenting the results of a daily diary study of sleep and pre-sleep arousal. Pre-sleep arousal is often implicated in poor sleep outcomes, although the arousal-sleep association is not uniform across age groups. The examination of intraindividual variability in different age groups may provide a more complete understanding of these constructs, which, in turn, can inform future research. The overall objectives of the current study are to quantify the amount of intraindividual variability in pre-sleep arousal and sleep and to examine age differences in this variability. A sample of older (n= 50) and younger (n= 50) adults recruited from North Central Florida and online completed 14-consecutive-day diaries assessing pre-sleep arousal and sleep outcomes. Significant age differences were found for sleep and pre-sleep arousal; older adults displayed poorer, more variable sleep for the majority of sleep outcomes, and higher levels of pre-sleep arousal than younger adults. The high amount of intraindividual variability has implications for the assessment of presleep arousal and sleep across age groups.
Keywords: Cognitive arousal, Somatic arousal, Sleep, Older adults, Intraindividual variability
PURPOSE: The severity of obstructive sleep apnoea (OSA) ranges from mild or moderate to severe sleep apnoea. However, there is no information available on the clinical characteristics associated with cases involving more than 100 events per hour. This is a preliminary report and our goal was to characterise the demographics and sleep characteristics of patients with Extreme OSA and compare with patients with sleep apnoea of lesser severity. We hypothesised that patients with Extreme OSA (AHI>100) is associated with an increased comorbidities and/or risk factors.
METHODS: We carried out a case-control study on male patients with OSA who were seen in a private hospital in Lima, Peru between 2006 and 2012. Cases were identified if their apnoea/hypopnea index (AHI) was higher than 100 (Extreme OSA), and four controls were selected per case: two with 15-29 AHI and two with 30-50 AHI, matched according to case diagnosis dates. We evaluated demographic, past medical history, and oxygen saturation variables
RESULTS: We identified 19 cases that were matched with 54 controls. In the multivariate model, only arterial hypertension, neck circumference, age, and over 10% in SatO2Hb ≤ 90% in total sleep time (T90) were associated with Extreme OSA. Arterial hypertension had an OR=6.31 (CI95%: 1.71-23.23) of Extreme OSA. Each 5-cm increment in neck circumference was associated with an increase of OR=4.34 (CI95%: 1.32-14.33), while T90>10% had an OR=19.68 (CI95%: 4.33-89.49). Age had a marginal relevance (OR=0.95; CI95%: 0.92-0.99)
CONCLUSION: Our results suggest that arterial hypertension, neck circumference, and over 10% SatO2Hb ≤ 90% in total sleep time were associated with a higher probability of Extreme OSA. We recommend investigators to study this population of Extreme OSA looking for an early diagnosis and the identification of prognostic factors in comparison with moderate to severe levels.
Keywords: Obstructive sleep apnoea, Disorders of excessive somnolence, Peru, Polysomnography
OBJECTIVE: Mild cognitive impaired (MCI) is viewed as a transitional stage from normal to dementia. The aim of this study is analyze the sleep disturbances in subjects diagnosed as carries MCI.
METHODS: A review of the literature was conducted in order to document sleeps problems in the context of MCI.
RESULTS: Among the studies that compares the prevalence of sleep disturbances between subjects with MCI and those with normal cognition demonstrated that night time behaviors are more common in MCI patients (18.3-45.5%) than in normal population (10.9-23.3%).
CONCLUSIONS: Sleep disturbance is prevalent and predictive of cognitive decline in older people and in those with neurodegenerative disorders. The sleep problems have to be identified and treat to preserve the cognition and the MCI subjects with sleep disturbances have to be follow more closely to identify the initial signs of dementia.
Keywords: Sleep disturbance, Mild cognitive impairment, Sleep apnea, Dementia, Elderly
OBJECTIVE: To evaluate the available literature regarding Upper Airway Resistance Syndrome (UARS) treatment.
METHODS: Keywords “Upper Airway Resistance Syndrome,” “Sleep-related Breathing Disorder treatment,” “Obstructive Sleep Apnea treatment” and “flow limitation and sleep” were used in main databases.
RESULTS: We found 27 articles describing UARS treatment. Nasal continuous positive airway pressure (CPAP) has been the mainstay therapy prescribed but with limited effectiveness. Studies about surgical treatments had methodological limitations. Oral appliances seem to be effective but their efficacy is not yet established.
CONCLUSION: Randomized controlled trials with larger numbers of patients and longterm follow-up are important to establish UARS treatment options.
Keywords: Upper airway resistance syndrome flow limitation, Treatment, Arousal, Daytime sleepiness
Streptococcal infections are suggested as a risk factor for narcolepsy. This hypothesis is supported by the presence of anti-streptolysin antibodies in 65% of patients with narcolepsy. These infections are associated with the activation of general immunity and concomitant increased permeability of blood-brain barrier after T cell activation during inflammation and fever.
It has also been shown a significant association between birth order and narcolepsy in genetically susceptible patients, with positivity for HLA-DQB1*0602 allele. Watson and colleagues showed a significant association between birth order and narcolepsy in genetically susceptible patients, with positivity for HLA-DQB1*0602 allele. In that study, the disease was predominant in young children cases compared to controls.
We report here the case of a child diagnosed with narcolepsy with cataplexy, positivity for the HLA-DQB1*0602 and previous history of streptococcal infection.
Keywords: Streptococcal infections, Childhood, Narcolepsy