SLEEP

Dijk,, Derk-Jan;Cajochen,, Christian;Tobler,, Irene;Borbély, Alexander, A.

doi: 10.1093/sleep/14.4.294pmid: 1947592

Summary: In eight male subjects the electroencephalogram (EEG) and core body temperature (Tcore) were recorded during long sleep episodes from 0000 to 1500 hr. EEGs were visuallv scored and subjected to spectral analysis by fast Fourier transform. Slow-wave sleep [SWS, i.e. stages 3 + 4 of non-rapid eye movement (NREM) sleep and slow-wave activity (SWA, mean EEG power density in the range of 0.75–4.5 Hz)} in NREM sleep attained highest values in the first 3 hr of sleep and lowest values in the morning hours when rapid eye movement (REM) sleep was at its maximum. Wakefulness was significantly enhanced in the last 3 hr of the recording period. Occasional NREM episodes containing SWS were observed in the late morning and early afternoon. However, no significant increase in SWS or SWA in the last 3 hr of the sleep episode over any of the preceding 3-hr intervals was present and SWA in this interval was significantly below the values observed at the beginning of sleep. The duration of NREM episodes varied significantly over the sleep episode. Analysis of the dynamics of SWA within NREM episodes revealed that SWA gradually rose during the episode. Consequently, SWA averaged per episode was positively correlated with episode duration. Tcore dropped in the initial part of sleep, rose during the morning hours and reached values in the afternoon that were higher than at the beginning of sleep. Thus the time course of Tcore dissociated from the time course of SWA. This indlicates that SWA in NREM sleep is not directly related to the variation in core body temperature. Sleep extension, Slow-wave sleep, Slow-wave activity, Rapid eye movement sleep, Body temperature, Circadian rhythms This content is only available as a PDF. © 1991 Association of Professional Sleep Societies

Bonnet, M., H.

doi: 10.1093/sleep/14.4.307pmid: 1947593

Summary: The current study reports the effect of 0–8-hr naps placed prior to two consecutive nights of total sleep deprivation. A total of 104 young adult male subjects were randomly assigned to one of four prophylactic nap conditions (0, 2, 4 or 8 hr). After a normal baseline night of sleep and a morning of baseline test performance, subjects returned to bed at 1200, 1600 or 1800 hr or not at all prior to a continuous operation that extended until each subject's normal bedtime on the third following night. All subjects who napped arose at 2000 hr, and all subjects maintained the same schedule of computer-administered performance tests throughout the sleep-loss period. Results indicated that performance and alertness in all nap conditions were improved in a dose-response fashion compared to a no-nap control throughout the first 24 hr of sleep loss. However, significant improvement in nap conditions compared to the no-nap condition was not seen in many variables during the second night of sleep loss. Whereas an 8-hr nap prior to an operation maintained performance at a high level for 24–30 hr, significant improvement in alertness and performance as compared to the no-nap control was also documented by shorter naps. No nap could reverse the profound loss of alertness seen during the second night of sleep loss. Sleep, Sleep deprivation, Continuous operations, Prophylactic nap, Psychomotor performance, Work schedule tolerance This content is only available as a PDF. © 1991 Association of Professional Sleep Societies

Feinberg,, J.;Floyd, T., C.;March, J., D.

doi: 10.1093/sleep/14.4.316pmid: 1947594

Summary: Sleep electroencephalograms (EEG) and electrooculograms were recorded in nine young adult males on a baseline night, a night in which they were deprived of an average of 3 hr 27 min of sleep by early awakening, and on a recovery night. Records were analyzed by visual sleep stage scoring and period-amplitude analysis; the results of both were tabulated by successive nonrapid eye movement periods (NREMPs) and rapid eye movement (REM) periods. Neither visually scored delta nor REM measures were affected by this substitution of waking for sleep. Although there was a significant increase in the 0-3-Hz time/epoch on the recovery night, this finding was not confirmed in the accompanying report. These results, taken in association with data from previous studies, are consistent with the hypothesis that, in an acute experiment, visually scored delta and computer-measured 0-3-Hz EEGs increase above the baseline levels only if there has been loss of stage 3/4 EEG (or of sleep) from the first two NREMPs. The findings here are inconsistent with older reports and indicate that further parametric data are required to construct a quantitative model of the relation of sleep EEG waveforms to the duration of prior waking. Sleep, EEG, Deprivation, Delta, Computer, Models This content is only available as a PDF. © 1991 Association of Professional Sleep Societies

Travis,, F.;Maloney,, T.;Means,, M.;March, J., D.;Feinberg,, I.

doi: 10.1093/sleep/14.4.320pmid: 1947595

Summary: This experiment evaluated further our previous finding that substitution of waking for the terminal 3–4 hr of sleep produces little or no increase in either visually scored or computer measures of delta sleep. Eleven young adults (mean age 24.5 yr) were studied on a baseline night, a night with sleep limited to an average of 188 min, and a recovery night. Visually scored sleep stages, eye movement activity and computer measures of 0-3 Hz were analyzed by nonrapid eye movement periods (NREMPs) and for all recorded sleep in each condition. In addition, we measured the heights, durations and areas under the curve manifested by the cyclic waxing and waning of 0–3-Hz integrated amplitude across sleep. Acute loss of 3.9 hr of sleep did not increase either visual or computer measures of delta electroencephalograms (EEG) on the recovery night, essentially confirming our previous findings. We hypothesize that augmentation of delta EEG above baseline levels after acute (one night's) sleep loss requires that disruption or loss of sleep from the first two NREMPs (or delta cycles). Rapid eye movement (REM) sleep durations on the recovery night were unaffected by the marked loss of REM sleep caused by partial deprivation. Although eye movements as well as stage REM were lost in the deprivation condition, eye movement density was significantly reduced rather than increased on the recovery night. This reduction is consistent with the hypothesis that REM activity varies inversely with sleep depth (or directly with central arousal level). The observations here, taken in association with previous results, suggest that a threshold for eye movement suppression by sleep deprivation in young adults lies in the range of 3–4 hr of prior sleep loss. Sleep, EEG, Deprivation, Delta, Computer, Models This content is only available as a PDF. © 1991 Association of Professional Sleep Societies

Smith,, Carlyle;Lapp,, Lorelei

doi: 10.1093/sleep/14.4.325pmid: 1947596

Summary: Animal studies have recently demonstrated that increases in rapid eye movement (REM) sleep and actual number of rapid eye movements (REMs) over normal levels followed successful learning of an avoidance task. These increases persisted for many days following the end of the training sessions. It was hypothesized that similar extended increases in REM sleep parameters would follow an intensive learning task in humans. Senior college students were sleep monitored following the end of their Christmas examinations. Results showed that there was a significant increase in the number of REMs observed following the exams as compared to baseline and control subject values. The number of extra REMs was most prominent during the fifth REM period of the night. A significantly increased REM density was observed at the fourth REM sleep period of the night. Results support the idea of REM sleep and/or the REMs themselves being involved in long-term memory processing several days after the end of training. Rapid eye movement sleep, Rapid eye movement density, Learning, Memory, Humans This content is only available as a PDF. © 1991 Association of Professional Sleep Societies

Buysse, Daniel, J.;Reynolds, Charles, F.;Monk, Timothy, H.;Hoch,, Carolyn, C.;Yeager, Amy, L.;Kupfer, David, J.

doi: 10.1093/sleep/14.4.331pmid: N/A

Abstract Summary Subjective sleep quality deteriorates with aging, but the extent to which this is a product of age itself, as opposed to the medical or psychiatric problems associated with aging, has not been carefully studied. To investigate this issue, we examined the subjective sleep quality of 44 healthy subjects between the ages of 20 and 30 (23 men, 12 women) using the Pittsburgh Sleep Quality Index (PSQI). All subjects underwent rigorous medical and psychiatric evaluations to verify that they were in excellent physical and psychological health. Significant age effects were noted for the global PSQI score and several PSQI component scores, but overall sleep quality for the majority (68.1 %) of 80-yr-olds fell within a categorically defined range for "good" sleepers. Measures of habitual sleep quality did not correlate strongly with most polysomnographic sleep measures, number of medications used or circadian measures in elderly subjects. These results show that subjective sleep quality does deteriorate in the healthy elderly, but not to the level seen in patients with sleep disorders. Extremely healthy elderly subjects appear to adapt in their perception of objectively disturbed sleep. Subjective sleep quality, Elderly, Aging, Pittsburgh Sleep Quality Index, Insomnia, Polysomnographic sleep This content is only available as a PDF. © 1991 Association of Professional Sleep Societies

Walters, Arthur, S.;Hening,, Wayne;Rubinstein,, Mitchell;Chokroverty,, Sudhansu

doi: 10.1093/sleep/14.4.339pmid: N/A

Abstract Summary Neuroleptic-induced akathisia (NIA) is motor restlessness caused by dopamine receptor blocking antipsychoticagents. Nine patients with NIA and I I patients with idiopathic restless legs syndrome (RLS) were studiedpolysomnographicalIy. The sleep disturbances were milder in NIA than idiopathic RLS but increased numbers ofawakenings and decreased sleep efficiencies were common to both groups. In addition, RLS patients demonstratedprolonged sleep latencies. Periodic movements in sleep (PMS) were present in only 5 of 9 patients with NIA butin alI I I patients with idiopathic RLS. In no NIA patient did we see the multiple, large amplitude, violent, restingmyoclonic jerks of the legs that we saw during wakefulness in some of our more severe cases of idiopathic RLS.NIA patients tended to experience inner restlessness and idiopathic RLS patients tended to experience leg paresthesiasas an antecedent to motor restlessness. Idiopathic RLS patients had symptoms that were worse at night and inrepose far more frequently than patients with NIA. NIA and idiopathic RLS have similarities and differences.Because both NIA and idiopathic RLS are characterized by motor restlessness and sleep disturbances, the pharmacodynamicsof antipsychotic medications may give clues as to both the cause and treatment of idiopathic RLS. Neuroleptic-induced akathisia, Restless legs syndrome, Sleep disturbances, Periodic movements insleep, Myoclonus This content is only available as a PDF. © 1991 Association of Professional Sleep Societies

Gillis, Anne, M.;Stoohs,, Riccardo;Guilleminault,, Christian

doi: 10.1093/sleep/14.4.346pmid: 1947598

Summary: Abnormalities of ventricular repolarization are associated with life-threatening ventricular arrhythmias. The effects of obstructive sleep apnea on the QT interval were evaluated in 12 male patients with obstructive sleep apnea syndrome (OSAS) who had no evidence of underlying cardiac, pulmonary or central nervous system disease. Seventy episodes of OSAS during nonrapid eye movement (NREM) sleep were randomly selected for analysis of RR and QT intervals. Differences in the QT interval, corrected QT interval (QTc) and RR interval just before the onset of apnea, at the end of apnea and during the postapnea hyperventilation period were compared. As expected, the RR interval prolonged considerably during OSAS (1,499 ± 128 msec) compared to quiet sleep (1,019 ± 131 msec, p <0.002) and decreased during the postapnea hyperventilation period (969 ± 152 msec, p <0.002). The QT interval was prolonged at the onset of apnea (482 ± 34 msec) compared to the active awake state (421 ± 10 msec, p <0.01). Further prolongation of the QT interval was observed during OSAS (528 ± 64 msec, p <0.002). The QT interval shortened abruptly during the postapnea hyperventilation period (435 ± 34 msec, p <0.002). The QTc was also prolonged during the onset of apnea (482 ± 34 msec) and shortened significantly during apnea (435 ± 34 msec, p <0.002) and during the postapnea hyperventilation period (423 ± 39 msec). Significant variations of the RR interval, QT and QTc intervals were not observed during episodes of NREM sleep after initiation of effective therapy in six patients. Thus, significant prolongation of the QT interval is observed during severe OSAS and abrupt shortening of the QT interval occurs during the postapnea hyperventilation period. Whether these abnormalities of ventricular repolarization are associated with the development of ventricular arrhythmias in this patient population remains unknown. Obstructive sleep apnea, QT interval, Corrected QT, Heart rate, Ventricular arrhythmias, Autonomic nervous system This content is only available as a PDF. © 1991 Association of Professional Sleep Societies

Cartwright, Rosalind, D.;Diaz,, Frank;Lloyd,, Stephen

doi: 10.1093/sleep/14.4.351pmid: 1947599

Summary: The Apnea Plus Hypopnea Index (A + HI) of 60 male positional sleep apneics was analyzed by sleep stage to determine if positional differences are limited to NREM sleep. Differences in apnea severity by sleep position were found to persist in REM sleep and to be of equal extent to those differences found in NREM sleep, despite the fact that there is also a significant increase in the frequency of apneic events associated with REM sleep. The positional effect persists in REM sleep, making treatments to control sleep posture a viable option. Sleep position, Apnea This content is only available as a PDF. © 1991 Association of Professional Sleep Societies