Relationship between self-rating and polygraphic sleep parameters — analysis of compiled data from 12 young Japanese adults —

An examination of the relationship of the self-rating sleep score to polygraphic sleep parameters was conducted. The self-rating sleep questionnaire, OSA, includes five sleep quality factors: sleepiness (Fl), sleep maintenance without interruption (F2), worry about daily life or poor emotional condition (F3), integrated or perceived sleep feeling (F4) and sleep initiation or induction (F5). Polygraphic sleep parameters including each sleep stage in minutes were used. If intercorrelation coefficients exceeded 0.8, only one of the related parameters was selected for multivariate analysis. Twelve male students slept a total of 88 nights, among which the first night was not included, in an experimental room. When absolute values of Spearman’s rank correlation coefficient of not less than 0.4 were tentatively selected, the following pairs were extracted: F2 score and S1 (-0.423) or S3+S4 (0.409), F5 score and sleep latency (-0.439). Deeper sleep was closely associated with sleep maintenance without interruption. Agreement between self-rating and a polygraphic sleep parameter was recognized between the F5 score and sleep latency. Each OSA factor score was predicted by other polygraphic sleep parameters using multiple regression analysis. MT significantly contributed to the Fl, F3 and F4 scores. The number of stage shifts per night significantly contributed to the Fl and F3 scores, and the number of sleep spindles significantly contributed to the F5 score. Though prediction of sleep quality by polygraphic sleep parameters is limited, the association between concrete subjective and objective sleep parameters was clarified as mentioned above, and their practical meaning was partially elucidated.     

Premature infants in car seats: effect of sleep state on breathing

SUMMARY  Previous studies have shown that premature infants may be at risk for hypoxemia and bradycardia when placed in standard car seats. However, the relationship of such breathing abnormalities to sleep state have not been studied. The purpose of the present study was to investigate the effect of car seat positioning on respiratory patterns in preterm infants during sleep and to evaluate their relationship to sleep state. Complete polysomnography, including sleep and breathing parameters, was performed on twenty-eight premature infants. Each infant was randomly assigned to the car seat or prone (crib) position for the first recording period. Following the recording of at least two sleep cycles, the position was reversed. The percentage of active and quiet sleep was calculated and breathing parameters were measured. In the car seat, the infants spent significantly more time in active sleep and less time in quiet sleep than in the prone position, of the respiratory parameters, periodic breathing (PB) was significantly higher in the car seat. The presence of at least one abnormal breathing events (bradycardia, desaturation, PB apnoea) was also significantly higher in the car seat. An analysis of variance (ANOVA) of PB revealed significant sleep-state effect (active vs. quiet sleep), but no significant condition or interaction effects, indicating that PB was more frequent in active sleep regardless of the sleeping condition. It is concluded that increased active sleep in the car seat condition, rather than the positioning of the infant in the seat per se, may account for the increase in periodic breathing and possibly other breathing abnormalities reported in car seats.     

Predictive value of specific risk factors, symptoms and signs, in diagnosing obstructive sleep apnoea and its severity

SUMMARY  A positive diagnosis of obstructive sleep apnoea (OSA) is based on a combination of characteristic symptoms and polysomnographic findings. The present study evaluated the specificity and sensitivity of several risk factors, signs and symptoms in predicting an Apnoea Index in 86 patients referred to the sleep laboratory with suspected OSA. All 86 subjects completed a detailed questionnaire, were interviewed, underwent a brief physical examination, and then a whole-night polysomnographic study. Stepwise multiple regression analysis revealed that self reporting on apnoeas, neck circumference index (NCI), age, and a tendency to fall asleep unintentionally, were all significant positive predictors of apnoea index (AI), explaining 41.8% of the variability. The sensitivity of the model for predicting OSA (taking OSA as AI>10) was 92.2%, specificity was 18.2% and the positive predictive value was 76.6%. Raising the cut-off AI values resulted in decreased sensitivity and increased specificity. Applying the predicting equation of AI to another group of 50 patients referred to the sleep laboratory with suspected OSA revealed similar results. However, running the equation on 105 offspring of OSA patients who did not complain of OSA-associated symptoms resulted in 32% sensitivity and 94% specificity in predicting OSA. It is concluded that questionnaires, interviews and physical examination, can only vaguely predict AI, and cannot replace polysomnographic recordings. However, the low rates of false negative in predicting AI > 10, and the low rates of false positive in predicting AI > 50, can be used for specific purposes.     

Intrathecal midazolam reduces isoflurane MAC and increases the apnoeic threshold in rats

Canadian Journal of Anesthesia/Journal canadien d'anesthésie - The purpose of this study was to examine the anaesthetic requirement of intrathecal midazolam in a dose-response fashion in...     

Aging does not affect the sleep endocrine response to total sleep deprivation in humans

Aging is associated with decreased sleep continuity, slow wave sleep (SWS), growth hormone (GH) release and an increased hypothalamo-pituitary-adrenocortical (HPA) system activity. Total sleep deprivation (TSD) is a strong stimulus for sleep. To determine if aging affects the response to TSD, for the first time the combined effects of TSD on conventional and spectral sleep electroencephalographic (EEG) parameters and GH, cortisol and prolactin secretion were compared in elderly (60–80 years; n = 7) vs. younger subjects (20–30 years; n = 7). MANOVA revealed a reduction of SWS in the elderly. TSD led to an increase in SWS, a decrease in sleep onset latency, rapid eye movement (REM) density and by trend REM-latency without a global group difference. GH was reduced, whereas prolactin was enhanced in the elderly. After TSD GH was unchanged and prolactin secretion was enhanced without group difference. Thus, the plasticity of the sleep-endocrine system in response to TSD is sustained during aging. The possible involvement of the GABAergic system, that seems not to be severely impaired with age, is proposed.     

Sleep problems and daytime behavior in childhood idiopathic epilepsy

PURPOSE: To evaluate the presence of sleep problems and their association with behavioral and adjustment problems in children with idiopathic epilepsy. METHODS: A parental questionnaire was used to assess sleep problems in 89 children with idiopathic epilepsy for comparisons with 49 siblings and 321 healthy control children, equally distributed for age and sex. Sleep problems were clustered into five factors: parasomnias, parent/child interaction during the night, sleep fragmentation, daytime drowsiness, and bedtime difficulties. Daytime behavior and psychological adjustment were assessed by means of the Child Behavior Checklist. Maternal distress and disturbance was evaluated by the Malaise Inventory. The better to identify factors associated with sleep problems in the children with epilepsy, multiple regression analysis was performed. RESULTS: Children with epilepsy showed significantly more sleep problems than did both siblings and healthy controls. Within the epileptic group, children with current seizures complained more of sleep problems than did the seizure-free children. Moreover, children with epilepsy showed more behavioral problems and maladjustment. Age, paroxysmal activity density, duration of illness, seizure frequency, and behavioral problems were significantly associated with sleep problems in the epileptic group. CONCLUSIONS: The results of this study in a highly selected sample pointed out the presence of sleep problems, and adjustment and behavioral problems in children with idiopathic epilepsy. The presence of epilepsy, although benign, in childhood is associated with adaptive problems of the child. From this point of view, the alteration of some sleep habits may be a sign of emotional maladjustment. Although parents failed to perceive them as a problem, our findings indicate that attention to sleep and behavioral problems is important in clinical management of children with idiopathic epilepsy.     

Lateralizing value of interictal spikes on overnight sleep-EEG studies in temporal lobe epilepsy

PURPOSE: To determine the lateralizing value of interictal epileptiform discharges (IEDs) recorded during overnight sleep-EEG studies in temporal lobe epilepsy. Because IEDs are more prevalent in non-rapid eye movement (NREM) sleep than in wakefulness, overnight sleep-EEG recordings may contribute additional lateralizing information to the epilepsy surgery evaluation beyond daytime EEGs. METHODS: Twenty-four subjects with medically refractory temporal lobe epilepsy underwent continuous overnight sleep-EEG recordings. Subjects were seizure free > or =24 h before study and receiving stable doses of medication. The IED foci recorded on overnight studies were compared with daytime EEGs, interictal samples, and ictal recordings during long-term monitoring, brain magnetic resonance images (MRIs), and surgical outcome. RESULTS: (a) In all 24 subjects, including 13 without IEDs on daytime EEGs, temporal IEDs were present during NREM sleep and were exclusively or predominantly (>95%) unilateral in 15 and bitemporal in nine. (b) Unilateral NREM IEDs were concordant with surface or depth ictal-onset regions in 14 subjects, even if MRIs were normal (three subjects) or surface ictal-onset regions were bilateral (five subjects). Eleven of 12 subjects with unilateral concordant NREM IEDs who have undergone surgery are seizure free. (c) Bitemporal IEDs were associated with postoperative seizures in all subjects with normal MRIs or widespread MRI abnormalities. However, all subjects with bitemporal IEDs and MRI hippocampal abnormalities concordant with ictal-onset regions had good to excellent surgical outcomes. CONCLUSIONS: When combined with other investigations, IEDs recorded on overnight studies add prognostic data to the epilepsy surgery evaluation not provided by daytime EEGs.     

Insulin-like growth factor-1 (IGF-1)-induced inhibition of growth hormone secretion is associated with sleep suppression

The hypothalamic growth hormone (GH)-releasing hormone (GHRH) promotes non-rapid eye movement sleep (NREMS). Insulin-like growth factor-1 (IGF-1) acts as a negative feedback in the somatotropic axis inhibiting GHRH and stimulating somatostatin. To determine whether this feedback alters sleep, rats and rabbits were injected intracerebroventricularly (i.c.v.) with IGF-1 (5.0 and 0.25 microgram, respectively) and the sleep-wake activity was studied. Compared to baseline (i.c.v. injection of physiological saline), IGF-1 elicited prompt suppressions in both NREMS and rapid eye movement sleep (REMS) in postinjection hour 1 in rats and rabbits. The intensity of NREMS (characterized by the slow wave activity of the EEG by means of fast-Fourier analysis) was significantly enhanced 7 to 11 h postinjection in rats. Plasma GH concentrations were measured in 30-min samples after i.c.v. IGF-1 injection in rats and a significant suppression of GH secretion was observed 30 min postinjection. The simultaneous inhibition of the somatotropic axis and sleep raises the possibility that the sleep alterations also result from an IGF-1-induced suppression of GHRH. The late increases in NREMS intensity are attributed to metabolic actions of IGF-1 or to a release of GHRH from the IGF-1-induced inhibition.     

近似熵和复杂度应用于睡眠脑电研究的比较

介绍了两种度量序列复杂性的方法,一种是Ｋａｓｐａｒ和Ｓｃｈｕｓｔｅｒ定义的复杂度算法,一种是最近新发展起来的度量序列复杂性的统计方法－近似熵。应用这两种方法对睡眠脑电各睡眠期提取复杂性的特征,并通过对比研究表明,近似熵是值得重视的,很有前景的复杂度度量方法。     

The 24-Hour Sleep Propensity Function: Experimental Bases for Somnotypology

The present study investigated the temporal structure of sleep propensity during 48 hours using an ultrashort 7-min sleep/13-min wake cycle. Eight subjects were tested under two experimental conditions of either attempting sleep, or resisting sleep after a monitored night in the laboratory. Electrophysiological recordings were carried out during the 7-min trials. The temporal structure and the overall level of sleepiness of the 48-hour sleep propensity functions calculated from the amount of total sleep in each trial revealed a high within-subjects stability. This was found both across the two days of the study within conditions, and across conditions. Also, diurnal levels of sleepiness were systematically related to nocturnal sleep parameters. Subjects having short nocturnal sleep latencies and higher sleep efficiencies slept more during the day. It is proposed that the structure and level of the sleep propensity function can be used to characterize individuals along two dimensions of somnotypology: "morningness-eveningness" and "sleepy-alert."