Night time versus daytime transient ischaemic attack and ischaemic stroke: a prospective study of 110 patients.
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OBJECTIVE: Ischaemic stroke occurs only in 20%-40% of patients at night. The aim of the study was to compare sleep and stroke characteristics of patients with and without night time onset of acute ischaemic cerebrovascular events. METHODS: A consecutive series of 110 patients with transient ischaemic attack (n=45) or acute ischaemic stroke (n=65) was studied prospectively by means of a standard protocol which included assessment of time of onset of symptoms, sleep, and stroke characteristics. An overnight polysomnography was performed after the onset of transient ischaemic attack/stroke in 71 patients. Stroke and sleep characteristics of patients with and without cerebrovascular events occurring at night (between midnight and 0600) were compared. RESULTS: A night time onset of transient ischaemic attack or stroke was reported by 23 (21%) of 110 patients. Patients with daytime and night time events were similar in demographics; risk factors; associated vascular diseases; clinical and polysomnographic sleep characteristics (including severity of sleep apnoea); and stroke severity, aetiology, and outcome. Only the diastolic blood pressure at admission was significantly lower in patients with night time events (74 v 82 mm Hg, p=0.01). CONCLUSIONS: Patients with night time and daytime transient ischaemic attack/stroke are similar in sleep and stroke characteristics. Diastolic hypotension may predispose to night time cerebrovascular events. Factors not assessed in this study probably account for the circadian variation in the frequency of transient ischaemic attack and acute ischaemic stroke. (+info)
Pacifier use and sudden infant death syndrome: results from the CESDI/SUDI case control study. CESDI SUDI Research Team.
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OBJECTIVES: To investigate the relation between pacifier use and sudden infant death syndrome (SIDS). DESIGN: Three year population based, case control study with parental interviews for each death and four age matched controls. SETTING: Five regions in England (population > 17 million). SUBJECTS: 325 infants who had died from SIDS and 1300 control infants. RESULTS: Significantly fewer SIDS infants (40%) than controls (51%) used a pacifier for the last/reference sleep (univariate odds ratio (OR), 0.62; 95% confidence interval (CI), 0.46 to 0.83) and the difference increased when controlled for other factors (multivariate OR, 0.41; 95% CI, 0. 22 to 0.77). However, the proportion of infants who had ever used a pacifier for day (66% SIDS v 66% controls) or night sleeps (61% SIDS v 61% controls) was identical. The association of a risk for SIDS infants who routinely used a pacifier but did not do so for the last sleep became non-significant when controlled for socioeconomic status (bivariate OR, 1.39 (0.93 to 2.07)). CONCLUSIONS: Further epidemiological evidence and physiological studies are needed before pacifier use can be recommended as a measure to reduce the risk of SIDS. (+info)
Electrolocation-communication discharges of the fish Gymnotus carapo L. (Gymnotidae: Gymnotiformes) during behavioral sleep.
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Technical problems have hampered the study of sleep in teleosts. The electrical discharges of Gymnotus carapo L. (Gymnotidae: Gymnotiformes) were monitored to evaluate their ease and reliability as parameters to study sleep. The discharges were detected by electrodes immersed in a glass aquarium and were recorded on a conventional polygraph. G. carapo showed conspicuous signs of behavioral sleep. During these periods, opercular beat rates were counted, electric discharges recorded, and the "sharp discharge increase" (SDI) of the orienting reflex was investigated. All 20 animals monitored maintained electrical discharges during behavioral sleep. The discharge frequencies during sleep (50.3 +/- 10.4 Hz) were not significantly different from those observed when the fish was awake and inactive (57.2 +/- 12.1 Hz) (Wilcoxon matched-pairs signed-ranks test, P>0.05). However, the SDI, which was prevalent in the awake fish, was not observed during periods of behavioral sleep. Additional observations showed that the species had cannibalistic habits. When presented with electrical discharges from a conspecific, the sleeping fish showed an initial decrease or pause in discharge frequency, while the awake fish did not have this response. We conclude that the electrical discharges of G. carapo were not conspicuous indicators of behavioral sleep. Discharges may have been maintained during sleep for sensory purposes, i.e., conspecific detection and avoidance of cannibalistic attacks. (+info)
Psychological management of intractable seizures in an adolescent with a learning disability.
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Psychological interventions aimed at seizure management are described with a 14-year-old boy with a learning disability and intractable epilepsy. Baseline records suggested that a majority of tonic seizures and 'drop attacks' were associated with going off to sleep and by environmental 'startles'. Psychological formulation implicated sudden changes in arousal levels as an underlying mechanism of action. Cognitive-behavioural countermeasures were employed to alter arousal levels and processes in different ways in different 'at-risk' situations. A multiple baseline design was used to control for non-specific effects of interventions on non-targeted seizures. Results suggested significant declines in the number of sleep onset and startle-response seizures were attained by these methods. Gains were maintained at 2-month follow-up. (+info)
Seasonal changes of human circadian rhythms in Antarctica.
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The human circadian rhythms in sleep, activity, plasma melatonin, and rectal temperature were explored under two conflicting time cues in Antarctica: an extreme photoperiod and a strict work schedule. The nine healthy male subjects stayed at the Antarctic zone (latitude 66.5-90 degrees south) for 15 mo including a 13-mo wintering at the Dome station (latitude 77 degrees south). Neither the phases nor the amounts of sleep and daily activity underwent a seasonal change. On the other hand, the peak phase of melatonin rhythm was phase delayed by 4.1 h in winter compared with summer. When the analysis is limited to the Dome data, the seasonal difference was reduced to 1.3 h. Similarly the trough phase of rectal temperature rhythm in two of three subjects was phase delayed by approximately 2 h in winter. From these findings, the sleep or activity rhythm is concluded to be reset predominantly by the work schedule, whereas the circadian rhythm in plasma melatonin and rectal temperature is substantially influenced by the photoperiod. (+info)
Circadian temperature and melatonin rhythms, sleep, and neurobehavioral function in humans living on a 20-h day.
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The interaction of homeostatic and circadian processes in the regulation of waking neurobehavioral functions and sleep was studied in six healthy young subjects. Subjects were scheduled to 15-24 repetitions of a 20-h rest/activity cycle, resulting in desynchrony between the sleep-wake cycle and the circadian rhythms of body temperature and melatonin. The circadian components of cognitive throughput, short-term memory, alertness, psychomotor vigilance, and sleep disruption were at peak levels near the temperature maximum, shortly before melatonin secretion onset. These measures exhibited their circadian nadir at or shortly after the temperature minimum, which in turn was shortly after the melatonin maximum. Neurobehavioral measures showed impairment toward the end of the 13-h 20-min scheduled wake episodes. This wake-dependent deterioration of neurobehavioral functions can be offset by the circadian drive for wakefulness, which peaks in the latter half of the habitual waking day during entrainment. The data demonstrate the exquisite sensitivity of many neurobehavioral functions to circadian phase and the accumulation of homeostatic drive for sleep. (+info)
Effects of typical antipsychotic drugs and risperidone on the quality of sleep in patients with schizophrenia: a pilot study.
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OBJECTIVE: To investigate the effects of a newer antipsychotic drug, risperidone (a potent serotonin 5-HT2A/2C and dopamine D2-receptor blocker), on the quantity and quality of sleep in patients with schizophrenia. DESIGN: Prospective pilot study. SETTING: Outpatient treatment at a mental health hospital. PATIENTS: Two groups of age- and sex-matched patients with schizophrenia receiving either risperidone (n = 8) or a typical antipsychotic drug (n = 8), and a group of age- and sex-matched controls (n = 8). OUTCOME MEASURES: Sleep quality, measured by a visual analogue scale, and sleep continuity, measured using a movement index calculated from actigraph data. RESULTS: Patients with schizophrenia had more disturbed sleep than controls. Compared with patients treated with typical antipsychotic drugs, patients treated with risperidone reported significantly better sleep quantity and quality as well as general functioning. CONCLUSION: Improvement by risperidone may be related to 5-HT2A/2C receptor blockade; however, further controlled studies are required to confirm these results. (+info)
Response to inspiratory resistive loading during sleep in normal children and children with obstructive apnea.
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The response to inspiratory resistance loading (IRL) of the upper airway during sleep in children is not known. We, therefore, evaluated the arousal responses to IRL during sleep in children with the obstructive sleep apnea syndrome (OSAS) compared with controls. Children with OSAS aroused at a higher load than did controls (23 +/- 8 vs. 15 +/- 7 cmH(2)O. l(-1). s; P < 0.05). Patients with OSAS had higher arousal thresholds during rapid eye movement (REM) vs. non-REM sleep (P < 0.001), whereas normal subjects had lower arousal thresholds during REM (P < 0.005). Ventilatory responses to IRL were evaluated in the controls. There was a marked decrease in tidal volume both immediately (56 +/- 17% of baseline at an IRL of 15 cmH(2)O. l(-1). min; P < 0.001) and after 3 min of IRL (67 +/- 23%, P < 0.005). The duty cycle increased. We conclude that children with OSAS have impaired arousal responses to IRL. Despite compensatory changes in respiratory timing, normal children have a decrease in minute ventilation in response to IRL during sleep. However, arousal occurs before gas-exchange abnormalities. (+info)