SLEEP

Groome, Lynn, J.;Bentz, Lynn, S.;Singh, Karan, P.

doi: 10.1093/sleep/18.2.77pmid: 7792495

Summary: Repeated alteration in episodes of quiet sleep and active sleep is a basic feature of behavioral state organization in human fetuses. When compared to normal fetuses, at-risk fetuses generally exhibit extended periods of no coincidence (PsNC), that is, associations between state variables that cannot be classified as a sleep state. The purpose of this study was to determine if fetuses with extended PsNC differ in other state measures from fetuses with short PsNC. Fetal heart rate and fetal eye and gross body movements were collected simultaneously on 85 normal human fetuses between 37 and 41 weeks gestation for a total of 9,135 minutes (mean 108.8 ± 12.7 minutes, range 85–130 minutes). We found that as percent PsNC increased, the frequency (r = 0.464, p < 0.0001) of state changes increased and the time spent in active sleep (r = −0.456, p < 0.0001) and the number of fetuses entering an awake state (χ2 = 4.26, p < 0.039) decreased. In contrast, percent PsNC was independent of the length of time spent in quiet sleep (r = 0.070, p > 0.05). We interpret these findings as an indication that extended PsNC may be the result of disruption of homeostatic control mechanisms during active sleep. Behavioral states, Human fetus, Active sleep This content is only available as a PDF. © 1995 American Sleep Disorders Association and Sleep Research Society

Weissbluth,, Marc

doi: 10.1093/sleep/18.2.82pmid: 7792496

Summary: A cohort of 172 children was followed from 6 months to 7 years of age to determine how nap patterns change with age and whether there was individual stability of nap patterns. Results showed that there were no differences in nap patterns based on gender, ordinal position, whether naps spontaneously disappeared or were stopped by the parents, and the number of naps at 6 months of age. Total daytime sleep remained a stable individual characteristic between 6 and 18 months of age. Age was associated with hours napping (r = −0.73, p < 0.001) and number of naps (r = −0.52, p < 0.001). A pattern of two naps per day was well established by 9–12 months of age and one afternoon nap by 15–24 months. The modal duration of naps from 2 to 6 years was 2 hours. During the 3rd and 4th year, napping occurred in the majority of children, but at decreasing rates. A minority of children were napping at 5 and 6 years and naps usually disappeared by age 7. Naps, Infants, Children This content is only available as a PDF. © 1995 American Sleep Disorders Association and Sleep Research Society

Mendelson, Wallace, B.

doi: 10.1093/sleep/18.2.88pmid: 7792497

Summary: In previous studies we have reported that the benzodiazepine hypnotic triazolam and the nonbenzodiazepine Zolpidem increase the likelihood that insomniacs will report having been asleep when awakened by an electronic tone of progressive intensity. It has not been known, however, whether this occurs with normal sleepers. In the present study we have administered placebo, flurazepam 30 mg and Zolpidem 10 mg to 15 normal sleepers and awakened them with an electronic tone at five points across the night. In contrast to previous reports with insomniacs, both compounds made only modest improvements in sleep. When all time points were combined, subjects reported having been asleep in 40.3, 42.9 and 47.9% of the trials on placebo, flurazepam and Zolpidem, respectively (ns). Subjects were accurate in their estimate of total time asleep, and this accuracy was not influenced by the drugs. Similarly, there were no effects on a variety of questions related to dreaming and other cognitive activity during sleep. These results suggest that the effects of these hypnotics, which have been described previously in insomniacs, are not found in normals. Further studies will be necessary to clarify whether such effects in insomniacs are related to the clinical efficacy of hypnotics. Flurazepam, Zolpidem, Insomnia, Sleep, Hypnotics This content is only available as a PDF. © 1995 American Sleep Disorders Association and Sleep Research Society

Mendelson, Wallace, B.

doi: 10.1093/sleep/18.2.92pmid: 7792498

Summary: We have shown previously that the benzodiazepine hypnotic triazolam alters the perception of being awake or asleep in insomniacs, making it more likely that they will report having been asleep when awakened by an electronic tone at various times of the night. In the present study, we examined the question as to whether this is also true for other benzodiazepines as well as for nonbenzodiazepine hypnotics. Ten insomniacs were given placebo, flurazepam 30 mg and Zolpidem 10 mg and were awakened at five times during subsequent sleep in a random-sequence repeated-measures study. Across all five awakenings following placebo, insomniacs reported being asleep with a frequency of 30.9%. This rose to 40.4% (ns) and 54.7% (p < 0.03) on flurazepam and Zolpidem, respectively. Subjects were also more likely to report having been dreaming during the awakening 5 minutes after “lights out” after receiving Zolpidem. A number of polygraphic measures of sleep, including sleep latency, total sleep and sleep efficiency, improved significantly on both drugs, and there was similar improvement in some global measures of quality of sleep. Neither drug altered the subjective sense of duration of time. These findings suggest that drug-induced alterations in the perception of being awake or asleep are not unique to benzodiazepines, but occur with the nonbenzodiazepine Zolpidem as well. Sleep, Benzodiazepines, Flurazepam, Zolpidem This content is only available as a PDF. © 1995 American Sleep Disorders Association and Sleep Research Society

Bonnet, Michael, H.;Gomez,, Steven;Wirth,, Oliver;Arand, Donna, L.

doi: 10.1093/sleep/18.2.97pmid: 7792499

Summary: Previous studies have shown that performance during sleep loss is improved by prophylactic naps as a function of varying nap length. Based on single-dose caffeine studies, a similar dose-response effect has been hypothesized on performance, alertness and mood during sleep loss. The present study compared the effects of repeated versus single-dose administration of caffeine and varying amounts of sleep taken prior to sleep loss on performance, mood and physiological measures during 2 nights and days of sleep loss. A total of 140 normal, young adult males participated at one of two study sites. Ninety-eight subjects at one site were randomly assigned to one of four nap conditions (0, 2, 4 or 8 hours) and 42 subjects at the second site were assigned to one of four caffeine conditions. After a normal baseline night of sleep and morning baseline tests of performance, mood and nap latency, subjects in the nap groups returned to bed at noon, 1600 hours, 1800 hours or not at all. Bedtimes were varied so that all naps ended at 2000 hours. Subjects in the caffeine groups received either a single 400-mg dose of caffeine at 0130 hours each night or repeated doses of 150 or 300 mg every 6 hours starting at 0130 hours on the 1st night of sleep loss. A placebo control group (no nap and placebo administered every 6 hours on the repeated caffeine schedule) was run at both sites. Subjects remained awake and followed the same schedule of computer-administered performance tests, mood scales, multiple sleep latency test observations and meals/breaks for 52 hours before being allowed a recovery night of sleep at their normal sleep time. Results are consistent with previous findings and suggest that performance, mood and alertness are directly proportional to prophylactic nap length. Furthermore, an 8-hour nap is superior in maintaining performance, mood and alertness to either single or repeated caffeine administrations. Naps, in general, provided longer and less graded changes in performance, mood and alertness than did caffeine, which displayed peak effectiveness and loss of effect within about 6 hours. Shorter prophylactic naps and small repetitive doses of caffeine, however, did maintain performance, mood and alertness during sleep loss significantly better than no naps or large single doses of caffeine. Neither nap nor caffeine conditions could preserve performance, mood and alertness near baseline levels beyond 24 hours, after which levels approached those of placebo. Sleep deprivation, Nap, Caffeine, Work schedules, Continuous performance, Prophylactic sleep This content is only available as a PDF. © 1995 American Sleep Disorders Association and Sleep Research Society

Benbadis, Selim, R.;Wolgamuth, Barbara, R.;Perry, Michael, C.;Dinner, Dudley, S.

doi: 10.1093/sleep/18.2.105pmid: 7792489

Summary: Dreams are closely associated with rapid eye movement (REM) sleep. The purpose of this study was to evaluate the reliability of dreams in predicting the presence of REM sleep during naps of the multiple sleep latency test (MSLT). We prospectively analyzed MSLTs performed in the evaluation of 44 patients with excessive daytime sleepiness. A total of 167 naps were studied. The patients' ages ranged from 11 to 69 years (mean 45 years). There were 26 males and 18 females. The relationship between the presence of reported dreams and the presence of REM sleep was as follows: sensitivity (percentage of naps with REM in which dreams were reported), 59%; specificity (percentage of naps without REM in which no dreams were reported), 63%; positive predictive value (probability that REM occurred if dreaming is present), 29%; and negative predictive value (probability that REM did not occur when no dreaming is present), 85%. In the daytime naps of the MSLT, the presence of reported dreaming did not appear to be a reliable indicator of the presence of REM sleep in the preceding nap. Résumé: Rêves et sommeil paradoxal sont étroitement associés. Le but de ce travail était de d'étudier si une telle association existe lors du test de latence multiple de sommeil. Nous avons analysé de façon prospective un total de 167 siestes chez 44 patients présentant une somnolence diurne excessive. L'âge des sujets allait de 11 à 69 ans (moyenne 45); 26 était de sexe masculin et 18 de sexe feminin. La corrélation entre rêves (rapportés) et la présence de sommeil paradoxal était la suivante: Sensibilité 59%, spécificité 63%, valeur prédictive positive 29%, et valeur prédictive négative 85%. Ainsi, la présence de rêves ne préjuge pas de la présence de sommeil paradoxal. En revanche, le seul paramètre fiable semble être la valeur prédictive négative; En l'absence de rêves, les chances que le sommeil paradoxal soit apparu sont très faibles. Le manque d'association entre rêves et sommeil paradoxal dans notre travail est due à la proportion inattendue (35%) de nos sujets qui ont rapporté une expérience onirique sans être entré en sommeil paradoxal. Plusieurs explications sont possibles en raison de notre méthodologie et de notre population, mais ce phénomène (activité onirique sans sommeil paradoxal) est également en accord avec plusieurs travaux modernes. Nous concluons que, lors des tests de latence multiple de sommeil, la présence de rêves à l'issue d'un somme n'est pas un signe fiable que le patient est entré en sommeil paradoxal. Multiple sleep latency test, REM sleep, Dreams This content is only available as a PDF. © 1995 American Sleep Disorders Association and Sleep Research Society

Meguro,, K.;Ueda,, M.;Kobayashi,, I.;Yamaguchi,, S.;Yamazaki,, H.;Oikawa,, Y.;Kikuchi,, Y.;Sasaki,, H.

doi: 10.1093/sleep/18.2.109pmid: 7792490

Summary: We investigated how sleep disturbance is correlated with brain lesions, cognitive impairment and decreased daily activity (ADL). Two hundred and four chronically ill patients including patients with vascular dementia were classified into eight groups based on cognitive function, ADL and grades of PVL (periventricular lucency) as shown by computerized tomography. Visual monitoring of the sleep/wake state was performed hourly for 14 consecutive days and the daytime sleep hours and the nighttime sleep hours were determined based on detected disturbances in the sleep/wake pattern. Whether any specific infarcted regions were correlated with sleep disturbance was also evaluated. We found that daytime sleep hours were increased and nighttime sleep hours were decreased by three single factors: cognitive impairment, decreased ADL and the severe grade of PVL. As for an interactive effect of the two factors, daytime sleep hours were increased by dementia with decreased ADL (independent of PVL) and increased by decreased ADL with the severe grade of PVL (independent of dementia). Although three factors affected sleep independently, ADL has an interactive effect on sleep with dementia and with PVL. No specific cortical regions related to sleep disturbance were found. Periventricular lucency, Vascular dementia, Daily activity, Sleep disturbance This content is only available as a PDF. © 1995 American Sleep Disorders Association and Sleep Research Society

White, David, P.;Gibb, Thomas, J.;Wall, John, M.;Westbrook, Philip, R.

doi: 10.1093/sleep/18.2.115pmid: 7792491

Summary: Obstructive sleep apnea is increasingly recognized as a common and debilitating disorder. As a result, a variety of diagnostic technologies have evolved to potentially decrease cost and improve access and ease of assessment. In this study we compared the Healthdyne NightWatch (NW) System (a home sleep diagnostic methodology) to standard polysomnography (PSG) in two sleep centers. Two separate studies were completed. NW was compared to a simultaneously obtained PSG in 30 patients (IN-LAB study). Seventy additional patients were studied in both the home with NW and in the laboratory with PSG (HOME-LAB study). The NW system records eye movement, leg movement, SaO2, nasal-oral airflow, chest and abdominal wall motion, body position and heart rate on a solid state recorder, which permits sleep staging based on body and eye movement and standard respiratory assessment. For the PSG, standard paper recording techniques were used. The IN-LAB study revealed a correlation between NW and PSG for total sleep time of r = 0.72, with NW tending to score some awake time as nonrapid eye movement sleep. The correlation for apnea-hypopnea index (AHI) was r = 0.94 between systems, with a sensitivity of 100% and specificity of 63.6% at an AHI threshold of 10. The HOME-LAB study demonstrated understandably poor correlations between NW and PSG for most measures of sleep, which is likely a product of night-to-night variability in sleep, home versus laboratory effects and the differences in sleep staging methodology. However, the correlation for AHI was r = 0.92, with a sensitivity of 90.7% and a specificity of 70.4% at an AHI threshold of 10. Using a new methodology to assess agreement between diagnostic systems, we observed 78.6% diagnostic agreement between NW and PSG in the HOME-LAB study, with NW underestimating AHI 4.3% of the time and overestimating it in 17.1% of cases. This may relate to night-to-night variability in AHI or greater NW computer sensitivity to subtle hypopneas. We conclude that NW provides an accurate determination of AHI in both the home and laboratory, using limited instrumentation. The analysis time for NW is also reduced compared to PSG, and patients generally prefer the NW evaluation. Sleep, Apnea, Home monitoring, Polysomnography This content is only available as a PDF. © 1995 American Sleep Disorders Association and Sleep Research Society

Reyner,, A.;Horne, J., A.

doi: 10.1093/sleep/18.2.127pmid: N/A

Summary: Home-based sleep was monitored by morning logs and wrist actimetry for 15 nights in a sample of 400 adults (20–70 years old; 211 female, 189 male; one per household). Subjects on sleep-enhancing medications and/or whose sleep was severely disturbed by illness were excluded. Subjects were grouped into age bands: (“young” = 20–34 years, “mid-aged” = 35–49 years and “older” = 50–70 years). Women retired to bed and fell asleep earlier than men. Men and women woke up earlier with increasing age. Sleep period time was markedly longer for women. Most reported awakenings were <5 minutes. Women reported more awakenings, more total time spent awake during the night and poorer sleep quality; all these findings were most evident in the older women, who also took longer to fall asleep than any other group. Although these age effects are consistent with those reported elsewhere, the gender effects, some of which are much stronger than the age effects, have not been so evident before. This content is only available as a PDF.

Penzel,, Thomas

doi: 10.1093/sleep/18.2.135pmid: 7792493

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