OBJECTIVE: The aim of this study was to evaluate the effects of acute administration of zolpidem (Zolp) on mice's habituation response to the open-field (OF) apparatus, a model of non-associative memory.
METHODS: Three-month old male Swiss mice were assigned to one of the following groups: Sal/HC, Sal/OF and Zolp/OF. Mice received an intraperitoneal (i.p. ) saline (Sal) injection and, 30 minutes later, they were returned to home cage (HC) (Sal/HC group) or exposed to the OF arena (Sal/OF). Still, a group of mice received an i.p. 10 mg/kg Zolp injection and 30 minutes later were exposed to OF. Animals were exposed to OF for 10 minutes and their general activity was quantified in the first 3 minutes. Ten days after the first exposure, all animals were submitted to a 3-minute OF exposure and their general activity was quantified.
RESULTS: In the first exposure, the Zolp/OF group presented a decreased peripheral, central and total locomotion frequencies and increased immobility duration in relation to the Sal/OF group. In the second exposure, only the Sal/OF group presented habituation behavior, demonstrated by a significant decrement of central and total locomotion frequencies and increased immobility duration when compared to Sal/HC group (exposed for the first time to OF). Conversely, Zolp/OF group did not differ from the Sal/HC group in any of the parameters analyzed, suggesting habituation impairment.
CONCLUSION: Our results suggest that the acute administration of 10 mg/kg Zolp before the first exposure to OF promotes a reduction on motor activity and induces habituation deficits, reflecting a non-associative memory impairment.

Keywords: sleep; memory/drug effects; memory/physiology; locomotion; motor activity; pyridines/administration & dosage; hypnotics and sedatives/pharmacology; rats.

OBJECTIVE: Sleepiness and naps occur in classrooms everywhere in the world. Poor seating posture is also common in classrooms. Even though poor posture causes students to be at risk for developing problems in the vertebral column, the relationship between sleep deprivation and bad postures has not yet received attention. Present study evaluated the viability of such hypothesis of link and tried to disclose other possibly involved factors.
METHODS: Twenty physicians, ten of whom were orthopedists, evaluated the possible risk to the vertebral column of 23 seating postures depicted in photos. Thirty-two skilled teachers testified they had frequently detected the occurrence of those postures displayed in the photos evaluated with the highest risk.
RESULTS: According to them, habit (90%), sleep deprivation (24%) and laziness (11%) are the main causal factors of these postures. Interviews carried-out with 50 scholars, 8 to 14 years old, both sexes, revealed that part of them has sleep debit frequently and gave additional information confirming it. Sleepiness during lessons was reported by 39 (78%) among 50 students and 22 (44%) of them said to have slept at least once during lessons. Sleepiness and laziness in the day following sleep reduction was recognized by 96% of the students, and 92% reported to sit differently on those days.
CONCLUSION: The obtained data seems to grant the pertinence of the hypothesis that sleep deprivation can be correlated to high risk bodily postures in classrooms and allows us to hypothesize about laziness involvement in this relationship.

Keywords: sleep deprivation; posture; sleep stages; schools; human body; spine/physiology; low back pain/diagnosis; arousal/physiology; human; child.

Delayed sleep phase disorder (DSPD) is characterized by delayed sleep-wake rhythm and is associated with a delayed melatonin secretion. The diagnosis of DSPD is based on clinical history, supported by actigraphy monitoring and sleep diary. Many sleep disorders present with similar symptoms to DSPD. Consequently, it is frequently misdiagnosed. The time of onset of endogeneous melatonin secretion (dim light melatonin onset - DLMO) can be reliably measured in saliva. Therefore, we investigated the potential added value of the DLMO test in diagnosing idiopathic DSPD. A literature search was performed to find relevant articles (search period: all articles published in preselected databases till March 18, 2010). Title and abstract were screened using predetermined inclusion and exclusion criteria. The relevance and validity of the selected articles were critically appraised. The literature search yielded 2,779 articles of which 4 were selected for critical appraisal. One study was considered relevant. This study evaluated the added value of DLMO in combination with polysomnography and sleep diary, but actigraphy was not used. The positive and negative predictive values of the test were both 87.5% and the added value of DLMO above sleep diaries combined with polysomnography was 32.5% in this study. Only one relevant study was found on the added value of DLMO in diagnosing DSPD. Further research on the added value of DLMO to clinical history and actigraphy monitoring is necessary.

Keywords: circadian rhythm; sleep stages; syndrome; sleep disorders, circadian rhythm; melatonin/secretion; polysomnography; sleep/physiology; sleep initiation and maintenance disorders; syndrome/diagnosis.

The treatment of choice for obstructive sleep apnea syndrome (OSAS) has been done with positive airway pressure devices, especially in moderate to severe cases. However, many patients do not adequately adhere to this therapy. Thus, other treatment modalities should be taken into consideration, including surgical procedures on the upper airway. This study describes the main techniques used on the soft palate and lateral pharyngeal wall to treat OSAS, as well as their indicators for success and their success rates. We also note the progress that has been made over the years in improving the surgical techniques that address the soft palate and lateral pharyngeal wall. We also highlight a critical selection of patients who have been treated using these procedures. When the indicators are carefully considered, surgical procedures may be beneficial in the treatment of OSAS.

Keywords: sleep apnea, obstructive; surgical procedures, operative; palate, soft; pharynx.

It is possible for normal subjects to fall asleep during daytime wakefulness, and the propensity for daytime sleep varies being high in the mid-afternoon and lower in the early evening 2 or 3 hours before overnight sleep onset. This lowering of propensity for sleep in the few hours that precede overnight sleep is a paradoxical phenomenon termed the "Forbidden Zone for Sleep" or "Wake Maintenance Zone". During the day, thyrotropin levels, which reflect the activity of the hypothalamus-pituitary-thyroid axis, oscillate in a predictable rhythm: lower levels during afternoon and higher levels during the early evening Forbidden Zone for Sleep. The steep increase in thyrotropin levels in the early evening is called the "thyrotropin-evening-surge", with the higher levels just before overnight sleep onset. Thereafter thyrotropin levels decrease over the rest of the night reaching their low daytime levels. Considering the well-known role of the thyroid in vigilance and alertness, we propose that the negative correlation between thyrotropin levels and propensity to sleep is not a coincidence. Assuming that the circadian rhythms of any species are turned to facilitate survival, we propose that the Forbidden Zone for Sleep is an inherent part of the human circadian rhythm increases biological fitness. In this article, a medical hypothesis, we present evidence that in human's circadian rhythms the Forbidden Zone for Sleep is secondary to the thyrotropin evening surge.

Keywords: sleep disorders, circadian rhythm; sleep-wake transition disorders; receptors, thyrotropin; thyroid hormones.

Sexual behavior can be associated with several stages of sleep, including both non-rapid eye movement and rapid eye movement stages of sleep. In narcoleptic patients, orgasmic cataplexy, or orgasmolepsy, and sexual hypnagogic hallucinations can be present. Although the association between narcolepsy and sexual behaviors has already been described, few reports describe the embarrassing circumstances for narcoleptic patients after vivid experiences during complex sexual hypnagogic hallucinations. This report describes an interesting case of a narcoleptic patient with sexual hypnagogic hallucinations associated with out-of-body experiences.

Keywords: narcolepsy; hallucinations; cataplexy; sexual behavior; sexuality; humans; male, adult; case reports.