Sleep spindles in adolescence: a comparison across sleep restriction and sleep extension

BackgroundThe tendency for adolescents to have restricted sleep has been examined in numerous studies; however, the impact of sleep restriction on adolescents’ neural activity during sleep (measured by electroencephalography (EEG)) is less extensively researched, particularly regarding sleep spindles.MethodsIn this experimental study, 34 adolescents attended a 10-day laboratory study where they received five consecutive nights of either 5 h, 7.5 h or 10 h of sleep opportunity, with one adaptation, one baseline and two recovery nights of 10 h of sleep opportunity before and after the experimental phase.ResultsBoth within- and between-subjects effects were observed for fast sleep spindle characteristics of density, duration and amplitude. Overall, when experiencing severe sleep restriction, fast spindles in adolescents were lower in amplitude and longer in duration. Sex differences were also seen for fast spindle amplitude.ConclusionsThis investigation adds to the knowledge in this field by investigating specific sleep spindle characteristics in the context of experimentally manipulated sleep. Sleep restriction is highly prevalent among adolescents. These findings indicate that chronic sleep restriction has an impact on brain activity related to sleep spindles.     

Sleep and respiration in the syndrome "apnea during sleep" in the child]

A sleep apnea syndrome has been diagnosed in eight children (age range 5-14). Before undertaking therapeutic trials, sleep and respiration were extensively studied. Sleep and respiration were again analyzed 3 months after tonsillectomy and adenoidectomy (6 cases) or tracheostomy with insertion of valve (2 cases). Sleep induced apneic apisodes in these children who had normal respiration during wakefulness. Three types of apnea (central, upper airway, and mixed) were recorded in each case. The minimum number of apneas recorded during a single night was 75; the maximum was 816. Polygraphic monitoring demonstrated greatly disturbed sleep. Sleep changes were quantitative as well as qualitative. REM sleep percent was decreased, but stages 3 and 4 NREM sleep were also impaired. A relationship between stages 3-4 NREM sleep and respiration was noted: stages 3-4 sleep disappeared when apneic episodes were numerous; no apnea was recorded during stage 4 sleep. Follow-up nocturnal recordings of two tracheostomized children with valve open, then closed, confirmed this "stage 4/no apnea" relationship. Apneas were also noted to induce marked sinus arrhythmia during sleep.     

Sleep spindles in children with restless sleep disorder,restless legs syndrome and normal controls

ObjectiveTo analyze and identify differences in sleep spindles in children with restless sleep disorder (RSD), restless legs syndrome (RLS) and normal controls.MethodsPSG (polysomnography) from children with RSD, RLS and normal controls were analyzed. Sleep spindle activity was detected on one frontal and one central electrode, for each epoch of N2 and N3 sleep. Sleep spindle density, duration and intensity (density × duration) were then obtained and used for analysis.ResultsThirty-eight children with RSD, twenty-three children with RLS and twenty-nine controls were included. The duration of frontal spindles in sleep stage N2 was longer in children with RSD than in controls. Frontal spindle density and intensity tended to be increased in RSD children. No significant differences were found for central spindles.ConclusionChildren with RSD had longer frontal spindles. This finding may contribute to explain the occurrence of excessive movement activity during sleep and the presence of daytime symptoms.SignificanceRecent research has demonstrated that children with RSD have increased NREM instability and sympathetic activation during sleep. Analyzing sleep spindles in children with RSD in comparison with children with RLS and controls adds to our understanding of the pathophysiology or RSD and its effects on daytime impairment.     

The sleep of dysthymic patients: a comparison with normal controls

All-night electroencephalographic (EEG) sleep recordings were compared in dysthymic patients and normal controls. Patients were selected according to DSM-III and underwent 2 weeks of treatment with placebo before the sleep evaluation, which also included self-assessments of sleep quality. As compared with normals, dysthymic patients demonstrated fragmented and superficial sleep with no changes in rapid eye movement (REM) sleep. In addition to sleep continuity disturbances, dysthymics had a higher percentage of stage 1 and a reduction of slow wave sleep (SWS), mainly due to a diminished percentage of stage 4. Other differences were related to a higher incidence of some EEG events, and it is suggested that the analysis of sleep microstructure is a useful approach to study sleep physiology in psychiatric patients. The classification of minor forms of depression is a controversial issue and therefore the nosological implications of our findings are discussed.     

Sleep in the elderly: normal variations and common sleep disorders

The most common complaints of older adults concern their difficulty initiating or maintaining sleep, which results in insufficient sleep and an increased risk of falls, difficulty with concentration and memory, and overall decreased quality of life. Difficulties sleeping are not, however, an inevitable part of aging. Rather, the sleep complaints are often comorbid with medical and psychiatric illness, associated with the medications used to treat those illnesses, or the result of circadian rhythm changes or other sleep disorders. Health care professionals specializing in geriatrics need to learn to recognize the different causes of sleep disturbances in this population and to initiate appropriate treatment. Nonpharmacological treatment techniques are discussed; pharmacological treatments are discussed in a companion article.     

Sleep in normal aging]

Sleep in the elderly is characterized by a decrease in the ability to stay asleep resulting in a more fragmented sleep. Spindles are less frequent and less ample, shorter, without an increase during the night contrary young subjects. Delta activity in slow wave sleep is decreased in the 0.5-2 Hz frequency band only. REM sleep occurs earlier the first REM period duration increases. The REM sleep appearance is almost uniform during the night. REMs density does not increase toward the end of the sleeping period. The sleep-wake circadian rhythm is advanced (bedtime and morning awakening occur earlier). The temperature rhythm is also advanced. The rise in temperature after the nadir begins earlier for females and the initial ascent is more rapid. This explains why women wake up earlier and sleep for shorter durations than men. The nocturnal and diurnal mean plasmatic norepinephrine values increase. The rhythm of cortisol secretion is advanced. The GH and melatonin peaks of secretion are decreased. The acrophase of melatonin rhythm is occurring later in the elderly. These results suggest a weakening of circadian structure in the course of aging and an altered relationship between the pacemakers driving melatonin and cortisol circadian rhythms.     

Sleep manifestations,sleep architecture in children with Eosinophilic esophagitis presenting to a sleep clinic

Study objectivesTo describe sleep manifestations, polysomnographic (PSG) findings, and specific sleep disorders in children with Eosinophilic Esophagitis (EoE).MethodsThis retrospective study included children with EoE who were referred to sleep clinics. Clinical manifestations, PSG variables, and diagnosis of sleep disorders were analyzed. Sleep architecture of patients with EoE was compared to control subjects.ResultsIn sum, 81 children with EoE met the criteria for entry into the analysis with a mean age of 10.1 ± 4.4 years. Of those, 46 children (57%) presented in the sleep clinic with active EoE symptoms, while 35 (43%) children did not have active EoE symptoms at presentation. Several sleep complaints were common in children with EoE, including snoring (62, 76.5%), restless sleep (54, 66.6%), legs jerking or leg discomfort (35, 43.2%) and daytime sleepiness (47, 58.0%). Comparing sleep architecture with controls, children with EoE had significantly higher NREM2 (P= < 0.001), lower NREM3 (P= < 0.001), lower rapid eye movement (REM) (P = 0.017), increased periodic leg movements (PLM) index (P= < 0.001) and increased arousal index (P = 0.007). There were no significant differences in the sleep efficiency between the EoE and control subjects. Common sleep diagnoses included obstructive sleep apnea (OSA, 30, 37.0%) and periodic limb movements disorder (PLMD, 20, 24.6%). Of note, we found a much higher percentage of PLMD in active EoE compared to inactive EoE (P = 0.004).ConclusionsChildren with EoE have frequent sleep complaints and several sleep disorders identified from the sleep study, including sleep-disordered breathing and PLMD. Analysis of sleep architecture demonstrates significant sleep fragmentation as evidenced by decreased slow-wave sleep and REM sleep and increased arousal index.     

Sleep in essential tremor: a comparison with normal controls and Parkinson's disease patients

BackgroundRecent studies have shed light on non-motor features of ET, such as depressive symptoms and cognitive changes, which might be attributed to pathophysiological changes in the brains of ET patients. Given these brain changes, we explored sleep abnormalities in ET patients.MethodsSleep was assessed using the Epworth Sleepiness Scale (ESS) and the Pittsburgh Sleep Quality Index (PSQI) in 120 ET cases, 120 normal controls, and 40 PD cases.ResultsThe mean ± SD (median) ESS score increased from normal controls (5.7 ± 3.7 (5.0)), to ET cases (6.8 ± 4.6 (6.0)), to PD cases (7.8 ± 4.9 (7.0)), test for trend p = 0.03. An ESS score >10 (an indicator of greater than normal levels of daytime sleepiness) was observed in 11 (9.2%) normal controls, compared to 27 (22.5%) ET cases and 10 (25.0%) PD cases (p = 0.008 when comparing all three groups, and p = 0.005 when comparing ET to normal controls). The global PSQI score was 7.8 ± 2.8 (7.5) in controls, 8.0 ± 3.3 (8.0) in ET cases, and 9.9 ± 3.9 (10.0) in PD cases. The ET case–control difference was not significant (p = 0.8), yet in a test for trend, PD cases had the highest PSQI score (most daytime sleepiness), followed by ET (intermediate), and lowest scores in controls (p = 0.02).ConclusionsSome sleep scores in ET were intermediate between those of PD cases and normal controls, suggesting that a mild form of sleep dysregulation could be present in ET.     

Sleep bruxism in children: sleep studies correlate poorly with parental reports

The prevalence of sleep bruxism (SB) is usually reported as highest during childhood and decreases with age. However, this is based on parental reports and self-reports in the absence of quantitative data. Moreover, although SB signs, symptoms, and cutoff criteria have been established in the adult population, they remain unassessed in the pediatric population.ObjectivesThis study aims to classify SB in children according to sleep variables and rhythmic masticatory muscle activity (RMMA) frequency indexes and to determine associations with objective signs and symptoms of SB in comparison with parental reports.Materials and MethodsThirty-two children (11.5 ± 0.3 years) recruited at the orthodontic clinic underwent a dental assessment and ambulatory sleep recording (type II). Parents responded to a validated screening questionnaire on tooth clenching and grinding. A two-step cluster analysis was performed to classify participants into RMMA frequency groups, as described subsequently, followed by one-way analysis of variance (ANOVA) to compare groups. Fisher's exact test was performed for analyzing the associations between the signs and symptoms according to RMMA.ResultsThree RMMA frequency groups were identified: low (n = 12), moderate–high (n = 13), and control (n = 7). Between-group comparisons for episodes per hour and bursts/hour were significant (p <0.001). No relationships were found between RMMA (presence/absence) and clinically assessed tooth wear or reports of tooth clenching or grinding or craniofacial complaints.ConclusionsRMMA frequency classification differs slightly between children and adults. No association was observed between parental reports and RMMA, suggesting the need to improve parental knowledge of children's SB.     

Sleep and breathing in sleep in children with breath-holding spells

Sleep recordings were obtained in 21 children with breath-holding spells to investigate the possible existence of breathing disorders in sleep. Sleep recordings revealed an increased amount of wake time within sleep and sleep stage 1, and decreased amounts of stages 2 and REM. None of the children had more than 20 apneic episodes during sleep. These findings support the hypothesis that breath-holding spells are a functional disturbance of psychological nature only.     

Sleep architectures of obstructive sleep apnea syndrome in the young child

The sleep architectures of obstructive sleep apnea syndrome (OSAS) in the young child (child-OSAS, n = 17; mean age: 5.9+/-2.7 years; male:female 14:3) were compared with that of OSAS in the adult (n = 19; mean age: 44.7+/-10.7 years; male:female 18:1) and that of primary snoring in the child (n = 5; mean age: 7.0+/-2.4 years; male:female 5:0). Child-OSAS and OSAS in the adult had the same severity in oxygen desaturation. Child-OSAS showed lower Apnea-Hypopnea Index compared with OSAS in the adult. Sleep continuity in child-OSAS was not impaired compared with OSAS in the adult. Sleep fragmentation in child-OSAS was not so remarkable. The quantity of slow wave sleep in child-OSAS was similar to that of primary snoring in the child. Both profiles of sleep architectures showed nearly the same pattern.     

The sleep of non-depressed patients with panic disorder: a comparison with normal controls

Arriaga F, Paiva T, Matos-Pires A, Cavaglia F, Lara E, Bastos L. The sleep of non-depressed patients with panic disorder: a comparison with normal controls. Acta Psychiatr Scand 1996: 93: 191–194. © Munksgaard 1996. All-night sleep EEG recordings were performed in non-depressed patients with panic disorder, agoraphobia, and a group of age- and sex-matched normal controls. Patients were selected according to DSM-IV and all subjects were studied under drug-free conditions. In addition to sleep continuity disturbances, patients with panic disorder have a reduced percentage of slow wave sleep, mainly due to diminished amounts of stage 4. REM sleep characteristics are identical in the two groups. When depressive co-morbidity and non-specific causes of insomnia are excluded, the sleep EEG of panic patients seems to be characterized by modest changes in sleep continuity and sleep architecture. These findings favour the existence of a neurophysiological frontier between anxiety disorders and depressive illness.     

Sleep,sleep disorders and inflammation in children

Sleep-disordered breathing (SDB) and, more specifically, obstructive sleep apnea (OSA), can lead to significant morbidities including cardiovascular morbidity and neurocognitive dysfunction in children. Oxidative stress and increased inflammatory process activity are thought to be linked to the morbid consequences of OSA. Clinical and laboratory-based approaches have shown that oxidative stress and inflammation may be further modulated by genetic, lifestyle and environmental factors. Surgical treatment for OSA in children has been shown to be at least partially effective at normalizing endothelial function, reducing levels of inflammatory markers, and improving lipid profile, the apnea–hypopnea index and sleep fragmentation.     

Sleep positions in children with Down syndrome and obstructive sleep apnea

ObjectivesTo assess sleep positions in children with both Down syndrome (DS) and obstructive sleep apnea (OSA) and determine if there is a preferred sleep position by severity of apnea.MethodsA single-center retrospective review of patients with both DS and OSA was performed. Caregivers reported sleep position utilized greater than 50% of observed sleep time. Accuracy of this report was confirmed through review of hypnograms from polysomnography studies.ResultsEighty-two patients met inclusion criteria. Median body mass index (BMI) was 26.6 and 56% of patients had a prior tonsillectomy and/or adenoidectomy. The mean obstructive AHI (OAHI) was 25.33 with 90.4% having severe OSA, 9.6% having moderate OSA, and no patients having mild OSA. Reported sleep positions were skewed towards lateral/decubitus (82.9%) compared to prone (11.0%) and supine (6.1%). This was consistent with hypnogram data where 71% of total sleep time in lateral/decubitus positions compared to prone (13%) and supine (6%). The median changes in sleep position per patient was 5 (IQR: 3–6). Lower BMI (p < 0.001, 95% CI: 0.32–1.13) and tonsillectomy (p < 0.001, 95% CI: 7.7–18.19) were associated with lower OAHI. Sleep position was not associated with age (p = 0.19), sex (p = 0.66), race (p = 0.10), ethnicity (p = 0.68) nor history of tonsillectomy (p = 0.34). Preferred sleep position was not correlated with OAHI (p = 0.78, r = 0.03) or OSA severity (p = 0.72, r = 0.03).ConclusionsThis study highlights the possibility that children with DS may have preferential sleep positions that cater to optimized airflow in the context of OSA although further prospective study is needed.