Continuous Polygraphic Recordings Research Articles

Sleep deprivation before stroke is neuroprotective: A pre-ischemic conditioning related to sleep rebound

Background and aimWe have previously shown in a rat model of focal cerebral ischemia that sleep deprivation after stroke onset aggravates brain damage. Others reported that sleep deprivation prior to stroke is neuroprotective. The main aim of this study was to test the hypothesis that the neuroprotection may be related to an increase in sleep (sleep rebound) during the acute phase of stroke. MethodsMale Sprague Dawley rats (n=36) were subjected to continuous polygraphic recordings for baseline, total sleep deprivation (TSD), and 24h after ischemia. TSD for 6h was performed by gentle handling and immediately followed by ischemia. Focal cerebral ischemia was induced by permanent occlusion of distal branches of the middle cerebral artery. Control experiments included ischemia without SD (nSD) and sham surgery with TSD (n=6/group). ResultsShortly after stroke, the amount of slow wave sleep (SWS) and paradoxical sleep (PS) increased significantly (p<0.05) in the TSD/ischemia, resulting in an increase in the total sleep time by 30% compared to baseline, or by 20% compared with the nSD/ischemia group. The infarct volume decreased significantly by 50% in the TSD/ischemia compared to nSD group (p<0.02). Removal of sleep rebound by allowing TSD-rats sleep for 24h before ischemia eliminated the reduction in the infarct size. Conclusion prestrokeSleep deprivation results in sleep rebound and reduces brain damage. Sleep rebound may be causally related to the neuroprotection.

The effects of spinal or mesencephalic transections on sleep-related erections and ex-copula penile reflexes in the rat.

The neural mechanisms of penile erections during paradoxical sleep (PS) remain unknown since it has yet to be the subject of neurophysiological investigation. Using a new experimental model for sleep-related erection research in freely behaving rats, neural transections were undertaken to definitively elucidate the effects of paraplegia on PS-related erections and to determine at which brain level the mechanisms underlying PS erectile activity are generated. Continuous polygraphic recordings, as well as ex-copula penile reflexes, were performed in male Sprague Dawley rats before and after spinal (n = 4) or mesencephalic (n = 6) transections. Spinal transections virtually eliminated PS-related erections. Following mesencephalic transections, PS remained qualitatively intact in all rats. PS erectile activity, however, was severely disrupted, as shown by a significant decrease in the total number of erections, the number of erections per hour, and the percentage of PS phases exhibiting an erectile event. Finally, spinal and mesencephalic transections had contrasting effects on ex-copula penile reflexes. Spinal transections significantly shortened the latency to reflex induction and increased the percentage of tests eliciting an erectile event, whereas mesencephalic transections significantly increased the latency to reflex induction without affecting the percentage of tests eliciting an erectile event. These data suggest that the brainstem is not sufficient for the generation of PS erectile activity even though it is sufficient for the generation of other classic PS phenomena. We conclude that neural structures rostral to the mesencephalopn (i.e., the forebrain) are essential for the maintenance and integrity of PS related-erections. The reflex erection data suggest that spinal transection removes a tonic descending inhibition of erections, whereas such an inhibition not only remains intact, but appears enhanced following mesencephalic transection. We hypothesize that the forebrain plays a facilitatory role in erectile control, at least in part, through disinhibition of brainstem tonic anti-erectile mechanisms.

Diagnostic de la narcolepsie-cataplexie: intérêt de l'enregistrement continu sous EEG ambulatoire. À propos de 20 observations

Ambulatory EEG (A-EEG) allows longterm polygraphic recording over 24 hours or more and proves to be particularly useful in the diagnosis of narcolepsy-cataplexy (N/C). We performed A-EEG using the Medilog 9000-8 channel system over a total of 36 24-hour periods in 20 consecutive N/C patients and recorded an average of 3.5 daytime sleep episodes, of which 2.2 were with SOREMP, AND 21 evening SOREMP (58%). A MSLT was performed using A-EEG in 16 cases. Continuous A-EEG proved to be more informative than the MSLT, and may represent a valid alternative to the classic continuous polygraphic recordings performed in the sleep lab, that are more cumbersome and costly. Although a full-night polysomnographic recording is still necessary whenever other sleep disorders are suspected in association with N/C, A-EEG is a first-line, practical method for the confirmation of N/C, which remains a clinical diagnosis.

Maximum limits of sleep deprivation time estimated by continuous polygraphic recordings: from two cases of 72 h sleep deprivation

Maximum limits of sleep deprivation time estimated by continuous polygraphic recordings: from two cases of 72 h sleep deprivation

Tests of Memory in Narcoleptics

This study attempted to evaluate the validity of self-reports of memory deficits in narcoleptics by comparing the scores of these patients with the scores of matched control subjects on standardized tests of memory function. After completing a short interview designed to elicit qualitative information about memory difficulties, 30 narcoleptic subjects and 30 control subjects completed the Wechsler Memory Scale (WMS), Rey-Auditory Verbal Learning Test, the Rey Complex Figure Test, Strub and Black's List of Letters, and the Symbol Digits Modalities Test (SDMT). In addition, the Profile of Mood States (POMS) was used to detect variation in performance due to anxiety or fatigue. Continuous polygraphic recordings were obtained during the testing to detect any changes in alertness. Subjects with narcolepsy experienced more difficulty in maintaining attention than control subjects, as evidenced by significantly more perseveration errors (p less than or equal to 0.01) on Strub and Black's List of Letters. Despite differences in their ability to sustain attention, there were no significant differences between narcoleptic and control subjects on measures of concentration (Digit Span from the WMS, and the SDMT). Furthermore, there was no objective evidence of memory impairment when the scores of narcoleptic and control subjects were compared on standardized tests of immediate and delayed recall, as well as on tests of verbal and visual memory.

Continuous observations of daytime EEG patterns in normal subjects under restrained conditions while sitting in armchair or on stool. Part 2. Awake state.

While stabilizing (though not completely) both behavioral and environmental factors as far as possible, observations of continuous awake EEG patterns and corresponding behavioral states were made in order to investigate the level of vigilance for extended periods of time in the daytime. The subjects were requested to maintain a constant posture while sitting in an armchair or on a stool, and continuous polygraphic recordings and simultaneous TV monitoring of the subjects' behavior were carried out. Inspections of the EEG records, the rating of simultaneous behavior shown by the subjects and subsequent data analysis produced the following results: 1) From evaluations of EEGs, EOGs and EMG and ratings of the corresponding behavioral states carried out for every 30-second epoch, six types of awake EEG patterns and four types of behavioral states could be defined. There was a strong correlation between the awake EEG pattern and the behavioral state. 2) Regular 6.0-7.0 c/s theta wave trains predominantly in the frontal area were observed in 16 out of 24 normal subjects (67%) in an awake state. In the theta-appearance group, the relative abundance and mode of appearance of theta wave trains varied greatly both intra- and interindividually. The appearance of the theta wave trains was not related to drowsiness and was presumed to reflect the emotional activity under higher levels of vigilance in the subjects.

Differential effects of persistent nociceptive stimulation on sleep stages

The purpose of this work was to investigate the sequence of modifications of sleep and pain parameters in a condition of persistent nociceptive stimulation. In freely moving cats carrying implanted electrodes, continuous polygraphic and behavioral recordings were collected 24 h a day for several consecutive days before and after treatment. Injection of formalin (2 ml, 37%) elicited continuous wakefulness (1–6 h) associated with behavioral manifestations of pain. This insomnia was followed by the delayed appearance of LS (light, slow wave sleep) DS (deep slow wave sleep) and REM (rapid eye movement sleep). On days 1 and 2 after injection, pain manifestations displayed a gradual decrease, while total sleep time (LS + DS + REM) slowly returned to normal levels. On day 1, the amount of LS was not modified, but DS and REM were greatly decreased. For 12 h after the first REM episode, REM was decreased while DS was already at the basal levels. Formalin elicited a long-lasting increase in EMG activity of the tibialis anterior muscle which was suppressed during REM and returned to higher levels afterwards. Prolonged wakefulness and delay in sleep stage appearance were also recorded when a 24-h sleep deprivation preceded formalin injection. In this condition, LS, DS and REM amount were at basal levels from their first reappearance, and a rebound in total sleep time and DS occurred on day 2 after the injection. After injection of smaller doses of formalin (0.5 ml, 8%), the amount of LS, DS and REM was at control levels since day 1. The results suggest that (1) the amount of sleep depends on sleep debt and on the level of pain intensity and (2) sleep stages are differentially sensitive to persistent pain.

Influence of Breast Feeding on Neonatal Behavior

AbstractForty‐six normal newborn infants were studied at the age of 6 to 7 days. Each infant was at first breast fed and at the next session was given a bottle feeding of the same amount of expressed breast milk on the same day. The neonatal behavior was assessed over two three‐hour periods following each feeding, during which continuous polygraphic recordings and observations were made. Our study consisted of four steps: an expressed breast milk bottle feeding (step 1), an equal holding time period (step 2), an equal sucking time period (step 3), and an equal holding and sucking time period using two kinds of bottles (step 4). Infants who were breast fed had a longer period of quiet sleep and slow heart rate in active sleep compared with those who were bottle fed.In step 4, there were no significant differences in the amount of quiet sleep and low heart rate in active sleep between breast and bottle feeding. From our results, each component of breast feeding alone such as the breast milk itself, the holding time, or the time for sucking does not have any specific positive influence on neonatal behavior.Rather, the study suggests that the total mother‐infant interaction during breast feeding results in positive influences on neonatal behavior.

Sleep-wake stages during the subjective night of the squirrel monkey

The study of the circadian sleep-wake cycle is beset by unique technical challenges. Continuous polygraphic recordings are necessary to characterize circadian phenomena; however, the traditional method of recording sleep at high (15 mm/sec) chart speed is impractical for continuous animal studies that may last several weeks at a stretch. A system to determine four sleep-wake stages (awake, transitional, non-REM, REM) from low chart speed (1.5 mm/sec) recordings was developed and validated by direct behavioral observation using four adult male squirrel monkeys prepared for chronic recording of EEG, EOG and EMG. The polygraphic stages “transitional,” non-REM and REM were highly correlated with behaivoral observations of sleep, although individual sleep stages could not be resolved by behavioral parameters alone.

1468 PHYSIOLOGICAL CHANGES INDUCED BY ENDOTRACHEAL INSTILLATION AND SUCTIONING IN CRITICALLY ILL PRETERM INFANTS WITH AND WITHOUT SEDATION

Endotracheal instillation and subsequent suctioning produces fluctuations in intracranial pressure (ICP), mean arterial pressure (MAP), heart rate (HR) and tissue oxygenation (PO2) in ventilated, sick preterm infants. In an attempt to evaluate whether these fluctuations could be minimized using parenteral administration of sedation, we studied seven sick preterm infants on intermittent mandatory ventilation with and without sedation on eight occasions. Phenobarbital 10 mg/kg IV was used for sedation. Continuous polygraphic recordings of ICP, MAP, HR and PO2 were obtained. Cerebral perfusion pressure (CPP) was calculated. Using Wilcoxson signed rank test, statistically significant increases in HR, MAP and ICP and a significant decrease in PO2 were observed in these infants using no sedation. However, using sedation, even though significant increases were observed in ICP and a decrease in PO2, they were less than that without sedation. When looked at the changes (Δ) brought about by sedation, resulted in significant blunting of these phasic changes induced by endotracheal instillation and suctioning in MAP, ICP, CPP and PO2. We conclude that sedation produces a significant physiologic advantage to eliminate fluctuations of MAP, ICP and CPP. Thus, this physiologic benefit may at least in part help prevent morbidity commonly observed in these infants.

Studies of arrhythmias by 24-hour polygraphic recordings: Relationship between atrioventricular block and sleep states

The relationship between AV conduction disturbances and sleep states was investigated using continuous polygraphic recordings for one full night. The results were as follows: (1) In the case of first-degree AV block, the phasic shortening of the PQ interval was observed during rapid eye movement (REM) sleep. (2) In the case of second-degree AV block (Wenckebach type), the conduction ratio increased transiently during REM sleep and significant relationships were observed between the number of nonconducted P waves and the mean heart rate in each sleep stage. (3) In the case of advanced AV block, complete AV block was observed less frequently during REM sleep and the period of falling asleep. Since the reproducibility of these results from night to night has not yet been investigated, additional evaluation is required.

Effects of nocturnal gamma-hydroxybutyrate on sleep/waking patterns in narcolepsy-cataplexy.

Continuous 48-hour polygraphic recordings of sleep/waking patterns were performed on 14 patients with narcolepsy-cataplexy before and after 7-10 days of treatment of their nocturnal sleep with gamma-hydroxybutyrate (GBH). GBH improved the quality of night sleep by increasing the amount of slow wave sleep, reducing stage I, increasing sleep efficiency (percentage of time in bed spent asleep), and reducing the number of periods of short sleep under 15 minutes. Also nighttime REM sleep was reduced in latency and became less fragmented. The daytime period contained less slow wave sleep and REM sleep, and fewer episodes of prolonged sleep. Patients experienced reduction or loss of daytime attacks of irresistible sleep, cataplectic attacks, and other auxiliary symptoms. Residual daytime drowsiness subsequently improved on low doses of methylphenidate. Tolerance did not develop and there were no serious toxic side-effects. Four of the patients had been refractory to previous combinations of antidepressants and high doses of stimulants.

Responsiveness to stimulation during paradoxical sleep in infants

11 healthy children were repeatedly studied during 2 sleep cycles in 2 sessions at 2, 6, 12 and 20 wk of life. Three acoustic stimuli, light and tactile stimulus were applied in a randomized order in intervals ranging randomly from 30 to 120 sec. Continuous polygraphic recordings were made of respiration, REMs, EEG and EMG of biceps and triceps brachii. The effect of stimuli on the length of paradoxical sleep, REMs and EMG was assessed. There were age-related changes in the number of REMs after stimuli. At 2 and 6 wk no stimulus elicited any change. At 12 wk the children responded with an increased number of rapid eye movements to acoustic stimuli, at 20 wk they responded to acoustic stimuli and light. The conclusion is that, as far as REMs are concerned, responsiveness during paradoxical sleep changes with age. There was a difference in the incidence of EOG responses and EMG responses. These findings show that it is not possible to assess responsiveness in infants during PS by one measure only.

The definition of waking stages on the basis of continuous polygraphic recordings in normal subjects

Polygraphic examinations were made during the day on 6 normal subjects. Simultaneous evaluation of EEG, EOG and EMG was carried out over 30 sec epochs. The data thus obtained were correlated with the various types of behaviour and activities during the day and then interpreted. Six conditions could be defined corresponding to different waking stages. The analysis of the material obtained shows that the existence of these waking stages is of interindividual validity.

Effects of lesions of the suprachiasmatic nuclei on paradoxical sleep and slow wave sleep circadian rhythms in the rat

Continuous polygraphic recordings were taken from four rats before and after total lesions of the suprachiasmatic nuclei. This lesion did not change the total amount of paradoxical sleep nor slow wave sleep over a 24-h period, but reduced the amplitude of their circadian variations by 50%. Control lesions rostral and caudal to the suprachiasmatic nuclei were without effect on these sleep stages.

The effects of amoxapine on electroencephalographic stages of sleep in normal human subjects

This paper reports on an investigation of the effects of the long-term administration of a new dibenzoxapine antidepressant, amoxapine, (200 mg/day), on the nocturnal sleep patterns of a group of normal young males. Continuous polygraphic recordings of sleep were made prior to, during and after discontinuation of the drug.

All-night polygraphic studies of nocturnal angina pectoris.

In 12 patients with nocturnal angina pectoris, all-night continuous polygraphic recordings were made, including electroencephalogram, electrooculogram, electromyogram, impedance pneumogram and electrocardiogram, and ECG was analyzed in relation to heart rate and sleep stages. Out of 58 episodes of ischemic ST, T changes which were recorded with the peak frequency between 4:00 and 6:00a.m., 24 were REM-associated and 21 occurred in awake state.The number of attacks per hour in individual sleep stages was most prominent in REM sleep stage. In 3 cases episodes were seen only in awake period, and in 1 case in NREM sleep stages alone.The analyses of ECG and heart rate during sleep disclosed that the attacks were not likely to be induced by REM-associated increase of heart rate and, in individual episodes, heart rate increase did not precede the ST, T changes. The triggering mechanism of attacks remains to be investigated.Two representative cases were presented.

Insomnia following parachlorophenylalanin in the rat

Intraperitoneal injection of 500 mg/kg of parachlorophenylalanin is followed by a significant decrease of both slow wave sleep and paradoxical sleep in the rat (as measured by continuous polygraphic recordings). There is a significant correlation between the decrease of cerebral serotonin, the decrease of slow wave sleep and the decrease of the rate of occurrence of paradoxical sleep.