SLEEP

Scher, Mark, S.;Richardson, Gale, A.;Salerno, Dawn, G.;Day, Nancy, L.;Guthrie, Robert, D.

doi: 10.1093/sleep/15.3.195pmid: 1621019

Summary Electroencephalographic (EEG) sleep studies of 25 preterm neonates with chronic lung disease (CLD) corrected to a fullterm postconceptional age were compared with recordings from two groups of neonates without CLD: a fullterm appropriate for gestational age group (9 patients) and a preterm group studied at a corrected term postconceptional age (15 patients). Electrographic/polygraphic studies were obtained using 21-channel EEG recordings. Scores were tabulated based on minute-by-minute visual analyses of sleep state, number and duration of arousals, body movements and rapid eye movements (REM). A significant reduction in the percentage of active sleep was noted in the CLD group compared to both control groups (31.15% vs. 47.01% and 52.9%, respectively). The mean percentage of indeterminate sleep was significantly increased in the study group as compared to both control groups (31.23% vs. 15.18% and 11.5%). In addition, significant differences were noted between the CLD group and the healthy preterm control group with respect to the number (0.29/minute vs. 0.13/minute) and duration (4.8 seconds vs. 2.94 seconds) of arousals as well as the total number of body movements (1.57/minute vs. 0.74/ minute). These data suggest that neurophysiological organization of the immature brain, as reflected in neonatal sleep architecture and continuity measures, is adversely affected in neonates with CLD. EEG sleep architecture and continuity measures may be helpful in predicting the longitudinal outcome of infants with CLD as this group is at risk for adverse neurodevelopmental outcome. Preterm neonates, Chronic lung disease, EEG sleep studies This content is only available as a PDF.

Pollak, Charles, P.;Wagner, Daniel, R.;Moline, Margaret, L.;Monk, Timothy, H.

doi: 10.1093/sleep/15.3.202pmid: 1621020

Summary Six unmedicated narcoleptic subjects and nine normal controls lived in a temporal isolation laboratory for 18-22 days. They were permitted to “free-run” for the last 9-13 days. Brief cognitive and motor performance tests were repeated on average six times per subjective day. They consisted of serial search, complex verbal reasoning tasks and manual dexterity of each hand. Only minor differences in performance were found between the narcoleptic subjects and controls. Narcoleptic subjects showed mild impairment of accuracy on the search task that could be explained by occasional lapses and an afternoon dip in performance. Narcoleptic subjects also tended to perform some tasks more slowly, but the group differences were not significant. Neither speed nor accuracy of performance of narcoleptic subjects decreased over the course of the experiment. By one standard of performance, therefore, all or nearly all of the sleep need of these subjects was met by the sleep they obtained in the laboratory. That amount, in turn, did not exceed the total sleep obtained by the normal controls. Significant time-of-day effects were found in narcoleptic subjects for speed of verbal reasoning (progressive slowing over the course of the day), manual dexterity (fluctuations in speeds) and accuracy of serial search (afternoon dip). These variations in performance could not be attributed to changes in core body temperature or to occurrences of naps or meals. Narcolepsy, Cognitive performance, Motor performance, Temporal isolation This content is only available as a PDF.

Thorpy, Michael, J.;Snyder,, Michael;Aloe, Flavio, S.;Ledereich, Philip, S.;Starz, Kenneth, E.

doi: 10.1093/sleep/15.3.212pmid: 1621021

Summary This study was undertaken to determine whether the use of triazolam by narcoleptic patients leads to improvement of nighttime sleep or excessive sleepiness. Ten narcoleptic patients, 5 males and 5 females, with complaints of sleep disturbance and aged between 18 and 60 years, were assigned to a single-blind within-subject crossover-designed study comparing placebo with 0.25 mg triazolam. All subjects completed sleep questionnaires and underwent 6 nights of polysomnography testing. Following an adaptation night, subjects received either triazolam or placebo for 2 nights. Objective tests of sleepiness (multiple sleep latency testing/maintenance of wakefulness test) were performed. Sleep efficiency and overall sleep quality were improved on all triazolam nights. Daytime excessive sleepiness was not reduced objectively after triazolam. This study demonstrates that the shortterm use of triazolam improves nocturnal sleep quality in narcoleptics. Studies of long-term administration of triazolam are required to determine if the improvement of nocturnal sleep is maintained. Narcolepsy, Triazolam, Nocturnal sleep, Excessive sleepiness This content is only available as a PDF. Author notes † †Current address: Departamento de Neurologia do Hospital das Clinicas da Faculdade de Medicina da USP, Av. Eneas Carvalho de Aguiar 255, Sao Paulo, CEP 05403, Brazil.

Takeuchi,, T.;Miyasita,, A.;Sasaki,, Y.;Inugami,, M.;Fukuda,, K.

doi: 10.1093/sleep/15.3.217pmid: 1621022

Summary We elicited isolated sleep paralysis (ISP) from normal subjects by a nocturnal sleep interruption schedule. On four experimental nights, 16 subjects had their sleep interrupted for 60 minutes by forced awakening at the time when 40 minutes of nonrapid eye movement (NREM) sleep had elapsed from the termination of rapid eye movement (REM) sleep in the first or third sleep cycle. This schedule produced a sleep onset REM period (SOREMP) after the interruption at a high rate of 71.9%. We succeeded in eliciting six episodes of ISP in the sleep interruptions performed (9.4%). All episodes of ISP except one occurred from SOREMP, indicating a close correlation between ISP and SOREMP. We recorded verbal reports about ISP experiences and recorded the polysomnogram (PSG) during ISP. All of the subjects with ISP experienced inability to move and were simultaneously aware of lying in the laboratory. All but one reported auditory/visual hallucinations and unpleasant emotions. PSG recordings during ISP were characterized by a REM/W stage dissociated state, i.e. abundant alpha electroencephalographs and persistence of muscle atonia shown by the tonic electromyogram. Judging from the PSG recordings, ISP differs from other dissociated states such as lucid dreaming, nocturnal panic attacks and REM sleep behavior disorders. We compare some of the sleep variables between ISP and non-ISP nights. We also discuss the similarities and differences between ISP and sleep paralysis in narcolepsy. Isolated sleep paralysis, Hypnagogic hallucinations, Sleep onset REM period (SOREMP), Sleep interruption, REM/W dissociation, Narcolepsy This content is only available as a PDF.

Schenck, Carlos, H.;Mahowald, Mark, W.;Kim, Suck, Won;O'Connor, Kevin, A.;Hurwitz, Thomas, D.

doi: 10.1093/sleep/15.3.226pmid: 1621023

Summary The clinical polysomnographic (PSG) reports of 2,650 consecutive adults studied during 41 months were reviewed retrospectively to identify all patients treated with fluoxetine or tricyclic antidepressants. The PSG reports of four other adult groups were also reviewed: periodic limb movement (PLM) disorder (n = 28); sleep terror/sleepwalking (ST/SW) (n = 54); rapid eye movement (REM) sleep behavior disorder (RBD) (n = 70); patients with clinically unremarkable sleep during two consecutive PSG studies (n = 30). Standard PSG recording and scoring methods were employed. A total of 1.5% (n == 41) and 2.0% (n = 52) of patients were receiving fluoxetine or tricyclics (amitriptyline or nortriptyline, n = 31; imipramine or desipramine, n = 16; protriptyline or trimipramine, n = 5). A selective association between fluoxetine and extensive, prominent eye movements in nonrapid eye movement (NREM) sleep was detected, utilizing Fisher's exact one-tailed statistic (p < 0.00001 for each comparison). The detection rates were fluoxetine, 48.8% (20/41); tricyclics, 5.8% (3/52); RBD, 4.3% (3/70); objectively normal sleepers, 3.3% (1/30); PLM, ST/SW, 0% (0/82). These groups had similar mean ages (31.5–45.4 years) and gender distributions (50.0-60.7% male), apart from RBD. The effect of fluoxetine, a potent and specific serotonin reuptake inhibitor, on NREM eye movements is postulated to derive from potentiation of serotonergic neurons that inhibit brainstem “omnipause neurons”, which, in turn, inhibit saccadic eye movements, thus resulting in disinhibited release of saccades. In addition, a 31-year-old man with obsessive-compulsive disorder developed RBD soon after starting fluoxetine therapy, which persisted at PSG study 19 months after fluoxetine discontinuation. Fluoxetine, NREM sleep eye movements, Polysomnography, Obsessive-compulsive disorder, Serotonin, REM sleep behavior disorder, Depression This content is only available as a PDF.

Bastien,, Celyne;Campbell,, Kenneth

doi: 10.1093/sleep/15.3.236pmid: 1621024

Summary The functional significance and topographical variation of the different components of the evoked K-complex were examined. In the first experiment, the intensity of the stimulus (80 and 60 dB SPL) and its riseand-fall time (2 and 20 milliseconds) were manipulated during nonrapid eye movement sleep. In the second experiment the tonal frequency (500, 1,000 and 2,000 Hz) of the stimulus was manipulated. In the first experiment, nine stimuli were presented every 10 seconds, whereas in the second, 20 consecutive stimuli were presented. The evoked K-complex consisted of two different negative components peaking at approximately 350 and 550 milliseconds, respectively, and followed by a positive component peaking at approximately 900 milliseconds. K-complexes were easier to elicit for high-intensity fast rise-and-fall time stimuli than for low-intensity slow rise-and-fall time stimuli. The probability of occurrence was not affected by the tonal frequency of the stimulus. When a K-complex was evoked, the amplitude and latency of N350, N550 and P900 remained invariant regardless of its intensity, rise-and-fall or its tonal frequency. The N550-P900 portion of the K-complex therefore appears to be an all-or-none phenomenon. On trials in which a K-complex could not be elicited, N350 was still visible although much attenuated. In these trials, its amplitude was further reduced when stimulus intensity was lowered. N350 might need to reach a certain critical threshold before the much larger N550-P900 complex is elicited. Résumé Le rô1e fonctionnel et les differences topographiques des composantes du complexe-K évoqué étaient examinés. Deux intensites (80 et 60 dB SPL), deux temps de montée (2 et 20 millisecondes) et trois fréquences (500, 1,000 et 2,000) étaient manipulés dans les stades 2, 3 et 4 du sommeil. L'intervalle interstimulus était de 10 secondes. Les résultats démontraient que le complexe-K évoqué consistait en deux pics negatifs ayant respectivement une latence approximative de 350 et 550 millisecondes et suivis d'un pic positif apparaissant vers 900 millisecondes. Les complexes-K étaient plus facilement évoqués sous les stimuli d'intensité élevée et de temps de montée rapide que sous les stimuli d'intensité faible et de temps de montée lent. La fréquence des tons n'affectait pas la probabilité d'évoquer un complexe-K. Lorsqu'un complexe-K était évoqué, l'amplitude et la latence des pics N350, N550 et P900 demeuraient invariables sous les differentes conditions. Le complexe-K semblait done obéir à la loi du “toutou-rien”. Lors des essais où des complexes-K ne purent être identifiés, N350 était visible malgré une atténuation d'environ 50%. Lors de ces essais, son amplitude était encore plus atténuée lorsque l'intensité était diminuée. N350 devrait done avoir à atteindre un certain seuil d'amplitude critique afin que le complexe N550-P900 soit subséquemment évoqué. NREM sleep, K-complex, Stimulus parameters, All-or-none phenomenon This content is only available as a PDF.

Hertz,, Gila;Fast,, Avital;Feinsilver, Steven, H.;Albertario, Claude, L.;Schulman,, Harold;Fein, Alan, M.

doi: 10.1093/sleep/15.3.246pmid: 1621025

Summary Twelve women in their third trimester of pregnancy and 10 age-matched nonpregnant controls underwent complete polysomnography for one night in the laboratory. Seven of the original women returned for a second study 3-5 months postpartum. During late pregnancy, women showed increased wake after sleep onset (WASO) and a lower sleep efficiency in comparison with the control group. The percentage of rapid eye movement (REM) sleep was significantly decreased and the percentage of stage 1 significantly increased compared to the nonpregnant group. At 3-5 months postpartum, a significant reduction in WASO and increased sleep efficiency were noted. However, only a slight increase was noted in REM sleep during the postpartum period compared to the prepartum period. The most frequent sleep complaints in the pregnant group were restless sleep, low back pain, leg cramps and frightening dreams. In summary, in accordance with their complaints, women in their third trimester demonstrated polysomnographic patterns of sleep maintenance insomnia. Sleep, Pregnancy, Maintenance insomnia, Low back pain, Leg cramps This content is only available as a PDF.

Salin-Pascual, Rafael, J.;Grandos-Fuentes,, Daniel;Galicia-Polo,, Lourdes;Nieves,, Estela;Roehrs, Timothy, A.;Roth,, Thomas

doi: 10.1093/sleep/15.3.252pmid: 1621026

Summary Sixteen subjects were assigned to a group using either placebo or biperiden, with eight subjects in each group. Both groups were studied for one acclimatization night, one baseline night, four nights of rapid eye movement (REM) sleep deprivation and two recovery nights. All the subjects received either placebo or 4 mg biperiden 1 hour before sleep during the four nights of REM sleep deprivation. During the baseline and the recovery nights both groups received placebo capsules. The results showed that REM sleep time during the REM sleep deprivation was reduced by 70-75% below the baseline night in both groups. The number of attempts to enter REM sleep was significantly reduced by biperiden as compared to placebo for each of the four REM sleep deprivation nights. Because the total sleep time in the biperiden group was reduced, the number of REM sleep attempts was corrected by the total sleep time. The adjusted number of REM sleep attempts was also significantly reduced in the biperiden group. REM sleep latency showed a reduction in the placebo group, whereas in the biperiden group REM sleep latency was unchanged throughout the deprivation nights. In the recovery night REM sleep time was increased in both groups, with no differences between the groups. The REM sleep latency showed a reduction in the first recovery night in both groups that persisted through the second recovery night. The above findings support the role of biperiden as a REM sleep suppressive drug. Muscarinic receptors, REM sleep deprivation, Biperiden, Human subjects This content is only available as a PDF.

Whyte, K., F.;Allen, M., B.;Fitzpatrick, M., F.;Douglas, N., J.

doi: 10.1093/sleep/15.3.257pmid: 1621027

Summary We previously reported that the best definition of hypopneas in the sleep apnea/hypopnea syndrome (SAHS) is based on reduction in thoracoabdominal movement. However, the repeatability of scoring hypopneas from thoracoabdominal movement has not been assessed, nor has the need to record flow as well as thoracoabdominal movement. Thus, two polysomnographers independently scored both apneas and hypopneas on all-night polysomnograms of patients with SAHS. There was close agreement between the polysomnographers for the number of hypopneas (r = 0.98; mean difference 11%) and for the number of apneas (r = 0.99; mean difference 8%). The agreement was similar for the durations of both hypopneas (r = 0.99; mean difference 13%) and apneas (r = 0.99; mean difference 11%). There was also close agreement between the total number of respiratory events scored with and without reference to the flow signal (r = 0.99; mean difference 1.4%) with a maximum under-recognition of 18 events per night in a subject with 237 apneas per night. Thus, hypopneas can be scored reproducibly. In addition, the value of always recording and scoring flow as well as thoracoabdominal signals is questioned. Sleep apnea/hypopnea syndrome, Polysomnography, Reproducibility This content is only available as a PDF.

Haraldsson,, Per-OHe;Carenfelt,, Christer;Knutsson,, Evert;Persson, Hans, E.;Rinder,, Johan

doi: 10.1093/sleep/15.3.261pmid: 1621028

Summary The aim of this study was twofold: first, to see if the prevalence of the sleep apnea syndrome (SAS) in a given population could be fairly estimated by our patient questionnaire, mainly based upon the 1979 American Sleep Association definition of SAS; and second, to investigate whether the severity of SAS could be similarly accurately measured by daytime polysomnography (DPSG), as an alternative to the more demanding all-night polysomnography (NPSG). Of 42 patients consecutively examined due to rhonchopathy, 18 had the clinical diagnosis of SAS, which was based on the three symptoms—snoring, sleep disturbances and diurnal hypersomnia—if reported to occur habitually. In 11 patients the diagnosis was established by NPSG [apnea index (AI) > 10]. However, in only 10 of the 18 cases NPSG indicated the diagnosis giving a positive predictive value of 56%. When comparing DPSG versus NPSG in 36 patients, the AI ranged from −23 to +65, and the mean AI value was found to be twice as high in the former (mean difference 9.0 ± 18.4; p < 0.01). The positive predictive value of DPSG was 63% (10/ 16). Both the self-report and DPSG were burdened with some 25% false-positive results, and DPSG gave far too variable AI values to be reliable in staging the disease. On the other hand, the negative predictive values were high, 96% (23/24) and 100% (20/20), respectively, indicating their usefulness for screening purposes. Sleep apnea syndrome, Validity, Daytime polysomnography, Self-report This content is only available as a PDF.