SLEEP

Wayenberg,, J-L.;Hasaerts,, D.;Franco,, P.;Valente,, F.;Massager,, N.

doi: 10.1093/sleep/18.4.223pmid: 7618018

Summary: Our aim was to study the intracranial pressure (ICP) variations during sleep in normal infants. Using a noninvasive method, ICP was measured continuously during polysomnography in 12 healthy infants aged from 1 to 11 months (median 3.5 months). We analyzed the variations of mean basal ICP, mean basal pulse pressure amplitude and maximal amplitude of both plateau and B-like waves between transient sleep, quiet sleep and rapid eye movement (REM) sleep. Mean ICP, mean pulse pressure amplitude and B-like wave amplitude increased significantly during transient sleep and REM sleep. Plateau waves occurred during transient sleep and especially REM sleep. By contrast, noninvasive ICP recordings were relatively flat during quiet sleep stages 2 and 3. ICP variations and pressure waves seem to be related to cerebrovascular changes associated with sleep. The physiological ICP variations during sleep must be known in order to allow correct interpretation of continuous ICP measurements in infants. Resume A l'aide d'une méthode non-invasive, nous avons étudié les variations de la pression intra-crânienne durant les différentes phases du sommeil du nourrisson normal. Nous avons enregistré la pression fontanellaire (PF) de manière continue dans le cadre d'une polysomnographie chez douze nourrissons normaux âgés de 1 à 11 mois (médiane 3.5 mois). Nous avons analysé les variations de la PF moyenne, de l'amplitude moyenne du pouls cérébral et de l'amplitude maximale des ondes de pression durant le sommeil transitoire (stade 1), le sommeil calme (stades 2 et 3) et le sommeil paradoxal (stade 5). La PF moyenne, l'amplitude moyenne du pouls cérébral et l'amplitude maximale des ondes cycliques (de type B) sont significativement plus élevées dans le sommeil transitoire et le sommeil paradoxal que lors du sommeil calme. Des ondes de pression soutenues (en plateau) surviennent durant le sommeil transitoire et surtout le sommeil paradoxal. L'association d'ondes en plateau et d'ondes de type B amples et pointues est caractéristique des stades transitoire et paradoxal et contraste avec l'aspect assez plat des enregistrements pratqués en sommeil calme, où seules des ondes de type B arrondies et de faible amplitude sont identifiables. Nos résultats démontrent l'importance des variations de la PF durant le sommeil des nourrissons normaux. Ces variations physiologiques de la PF doivent être connues de manière à pouvoir interpréter de manière correcte les enregistrements de PF réalisés chez des nourrissons suspects de pathologie neurochirurgicale. Infant, Intracranial pressure, Noninvasive measurement, Plateau waves, Sleep stages Footnotes * This work was presented at the IXth International Symposium on Intracranial Pressure, Nagoya, Japan, 1994. This content is only available as a PDF.

Zammit, Gary, K.;Kolevzon,, Alexander;Fauci,, Margaret;Shindledecker,, Richard;Ackerman,, Sigurd

doi: 10.1093/sleep/18.4.229pmid: N/A

Summary: Twenty-one healthy men between 18 and 30 years of age were studied to determine the effects of midday food intake on sleep. Twelve subjects were administered liquid carbohydrate meals at lunchtime on 2 consecutive days. Subjects slept on 22 of the 24 study days for an average of 93 minutes during 3 hours of postprandial polysomnographic recording. Nine subjects were used as controls and were deprived of a lunch meal. Six of the nine subjects slept for an average of 30 minutes during the postprandial period. This time was significantly shorter than that of subjects in the meal condition (p < 0.005). There was no difference in latency to sleep onset following food intake between the two study groups. The results of this study suggest that lunchtime food intake does not promote the initiation of sleep, but that it does increase the duration of sleep episodes occurring during the postprandial period. This content is only available as a PDF.

Edinger, Jack, D.;Fins, Ana, I.

doi: 10.1093/sleep/18.4.232pmid: 7618020

Summary: It is well recognized that sleep time misperceptions are common among insomniacs, but little is known about the distribution and clinical significance of these subjective distortions. The current investigation was conducted to examine the distribution of sleep time misperceptions among a large (n =173), diverse group of insomniacs and to determine if such misperceptions might relate to the patients' clinical characteristics. Consistent with previous studies, our subjects, as a group, produced sleep estimates that were significantly (p < 0.0001) lower than poly-somnographically determined sleep times. However, patients' sleep time perceptions were widely distributed across a broad continuum, which ranged between gross underestimates and remarkable overestimates of actual sleep times. Results also showed that subgroups, formed on the basis of presenting complaints and diagnostic criteria (i.e. International Classification of Sleep Disorders nosology), differed in regard to the magnitude and direction of their sleep distortions. Moreover, these differences appeared consistent with the types of objective sleep disturbances these subgroups commonly experience. Hence, the tendency to underestimate actual sleep time is not a generic attribute of all insomniacs. Furthermore, it appears that the accuracy and nature of sleep time perceptions may relate to the type of sleep pathology underlying insomniacs' presenting complaints. Insomnia, Sleep misperception. This content is only available as a PDF.

Morin, Charles, M.;Colecchi,, Cheryl;Brink,, Doug;Astruc,, Manual;Mercer,, James;Remsberg,, Stephanie

doi: 10.1093/sleep/18.4.240pmid: 7618021

Summary: This study examined the accuracy of insomnia patients and their treating physicians in rating whether an active hypnotic drug or a placebo was given in treatment. Forty older adults with primary insomnia were randomly assigned to either an active (temazepam) or a placebo condition using a double-blind strategy. Ratings of treatment conditions were obtained at 1 week (early treatment), 4 weeks (midtreatment), and 8 weeks (late treatment). Patients were able to accurately discriminate (beyond chance levels) between the active and placebo medications at the early (76.9% accuracy) and late treatment assessment timepoints (78.1% accuracy), but not at midtreatment (51.5% accuracy). Therapists, however, were able to make accurate discriminations at the late treatment assessment timepoint only (80% accuracy); early (69.2% accuracy) and midtreatment (47.2% accuracy) ratings did not exceed chance levels. Patients who had used hypnotic drugs prior to this trial were more accurate in their judgments of treatment conditions than those without prior exposure. The findings raise an important issue about the internal validity of the double-blind strategy, which may in fact be only a single-blind procedure. This content is only available as a PDF.

Roth,, Thomas;Roehrs,, Timothy;Vogel,, Gerald

doi: 10.1093/sleep/18.4.246pmid: 7618022

Summary: Transient insomnia may be induced by stress, sleep in unfamiliar surroundings, jet lag and other factors. Zolpidem, a novel imidazopyridine hypnotic, has been shown to have hypnotic properties in most patients without significantly affecting next-day performance. Using the first-night effect in a sleep laboratory as a model of transient insomnia, this placebo-controlled, double-blind, parallel-group study evaluated the efficacy and safety of zolpidem in 462 normal volunteers. Zolpidem was tested at doses of 5, 7.5, 10, 15 and 20 mg, and statistical analysis of 7.5 mg and 10 mg was compared with placebo (unbalanced randomization). Compared with placebo, the 7.5 mg and 10 mg doses of Zolpidem decreased sleep latency and increased sleep duration and maintenance (i.e. reduced number of awakenings). Zolpidem (7.5 mg or 10 mg) had no significant effect on next-day psychomotor performance. No statistically significant differences in the overall side-effect profiles were found between 7.5-mg and 10-mg zolpidem dose groups and placebo. This study demonstrates that zolpidem at 7.5 mg and 10 mg is effective in the treatment of transient insomnia. Hypnotics, Sedatives, Insomnia, Zolpidem, Imidazopyridines, Sleep, Wakefulness, Sleep stages. This content is only available as a PDF.

Drinkenburg, W. H. I., M.;Coenen, A. M., L.;Vossen, J. M., H.;, van Luijtelaar, E. L. J. M.

doi: 10.1093/sleep/18.4.252pmid: 7618023

Summary: The effects of sleep deprivation were studied on the occurrence of spike-wave discharges in the electroencephalogram of rats of the epileptic WAG/Rij strain, a model for absence epilepsy. This was done before, during and after a period of 12 hours of near total sleep deprivation. A substantial increase in the number of spike-wave discharges was found during the first 4 hours of the deprivation period, whereas in the following deprivation hours epileptic activity returned to baseline values. Immediately after termination of deprivation, a decrease in the number of spike-wave discharges parallelled a rebound of rapid eye movement (REM) sleep and deep non-REM sleep. An initial increase in epileptic activity has also been reported during sleep deprivation of humans. This initial increase as well as the epileptogenic effects during the course of the sleep deprivation and during the recovery period after sleep deprivation can be interpreted in terms of changes in sleep-wake states. Although the epilepsy-provoking mechanisms are not yet understood, an explanation is suggested based on changes of transitions between sleep-wake states and shifts in level of synchronization. Epilepsy, Sleep deprivation, Sleep-wake states, Spike-wave discharges, WAG/Rij rats. This content is only available as a PDF.

Guevara, M., A.;Lorenzo,, I.;Arce,, C.;Ramos,, J.;Corsi-Cabrera,, M.

doi: 10.1093/sleep/18.4.257pmid: 7618024

Summary: Inter- (INTERr) and intrahemispheric (INTRAr) electroencephalographic (EEG) correlations were assessed in eight young male adults during wakefulness with eyes closed before going to sleep, and during stage 2, stage 4 and paradoxical sleep (PS) on the second night spent at the laboratory. Pearson product-moment correlations were calculated between EEG signals of every pair of electrodes (C3, C4, F3, F4, T3, T4) for six bands and for every 0.5 Hz from 1.5 to 15 Hz. Previous results of higher INTERr during sleep compared to during wakefulness were confirmed for the delta and theta bands during stage 2 sleep and PS and for sleep spindles during stage 2 sleep. The present results extend these findings to INTERr between F3 and F4 and during stage 4 sleep. INTRAr of 1.5–6.5 and 11–15 Hz was significantly higher during stages 2 and 4, whereas during PS INTRAr did not change. These data show that cortical changes during sleep are also observed in functional differentiation between cortical sites. Inter- and intrahemispheric differentiation is attenuated during stage 2 and 4 sleep, whereas during PS only interhemispheric differentiation is attenuated but intrahemispheric differentiation maintains similar levels of wakefulness. The attenuation of cortical differentiation may be of relevance for the understanding of mental activity changes during sleep. Interhemispheric EEG correlation, Intrahemispheric EEG correlation, Sleep, Wakefulness. This content is only available as a PDF.

Zarcone, Vincent, P.;Benson, Kathleen, L.

doi: 10.1093/sleep/18.4.266pmid: 7618025

Summary: Rapid eye movement (REM) sleep middle ear muscle activity (MEMA) was recorded in four diagnostic groups: schizophrenics (n = 18), schizoaffectives (n = 8), depressives (n = 11) and healthy, nonpsychiatric controls (n = 10). Previous work suggested that schizophrenics have higher than normal rates of REM sleep MEMA; this previous study employed the MEMA recording technique of impedance audiometry, which involves a 90-dB stimulus probe tone. The present study, which utilized a silent, pressure-sensitive transducer (i.e. no acoustic stimulus), was undertaken to determine if the stimulus tone might have elicited excess MEMA in the schizophrenics. In this present study, we observed no significant differences in REM sleep MEMA among the four diagnostic groups, suggesting that REM sleep MEMA cannot be used as a biological marker to differentiate clinical disorders. This failure to replicate our previous finding of high MEMA rates in schizophrenics is likely due to sampling error; alternatively, high REM sleep MEMA rates might be elicited in a subgroup of schizophrenics with an acoustic stimulus. Schizophrenia, Middle ear muscle activity, Rapid eye movement sleep. This content is only available as a PDF.

Altose,, Michael;Redline,, Susan;Johnson,, Xenia;Wright, Jackson, T.

doi: 10.1093/sleep/18.4.272pmid: 7618026

Article PDF first page preview Close This content is only available as a PDF.

Webb, Wilse, B.

doi: 10.1093/sleep/18.4.276pmid: 7677896

Summary: This journal published a special report titled “The Cost of Sleep-Related Accidents: A Report for the National Commission on Sleep Disorders Research”. The report estimated that sleep-related accidents were annually associated with 23,318 fatalities, between 1,907,072 and 2,474,430 disabling injuries and costs between $43.15 billion and $56.02 billion. This paper reanalyzes the data base and assumptions underlying these estimates and concludes that they greatly overestimated the probable relationship between sleepiness and accidents. A more moderate estimate of this important relationship is proposed. Accidents, Motor-vehicle accidents, Sleepiness This content is only available as a PDF.