The brain decade in debate: VII. Neurobiology of sleep and dreams

This article is a transcription of an electronic symposium held on February 5, 2001 by the Brazilian Society of Neuroscience and Behavior (SBNeC) during which eight specialists involved in clinical and experimental research on sleep and dreaming exposed their personal experience and theoretical points of view concerning these highly polemic subjects. Unlike most other bodily functions, sleep and dreaming cannot, so far, be defined in terms of definitive functions that play an ascribable role in maintaining the organism as a whole. Such difficulties appear quite clearly all along the discussions. In this symposium, concepts on sleep function range from a protective behavior to an essential function for maturation of the nervous system. Kleitman's hypothesis [Journal of Nervous and Mental Disease (1974), 159: 293-294] was discussed, according to which the basal state is not the wakeful state but sleep, from which we awake to eat, to protect ourselves, to procreate, etc. Dreams, on the other hand, were widely discussed, being considered either as an important step in consolidation of learning or simply the conscious identification of functional patterns derived from the configuration of released or revoked memorized information

The brain decade in debate: VII. Neurobiology of sleep and dreams.

This article is a transcription of an electronic symposium held on February 5, 2001 by the Brazilian Society of Neuroscience and Behavior (SBNeC) during which eight specialists involved in clinical and experimental research on sleep and dreaming exposed their personal experience and theoretical points of view concerning these highly polemic subjects. Unlike most other bodily functions, sleep and dreaming cannot, so far, be defined in terms of definitive functions that play an ascribable role in maintaining the organism as a whole. Such difficulties appear quite clearly all along the discussions. In this symposium, concepts on sleep function range from a protective behavior to an essential function for maturation of the nervous system. Kleitman's hypothesis [Journal of Nervous and Mental Disease (1974), 159: 293-294] was discussed, according to which the basal state is not the wakeful state but sleep, from which we awake to eat, to protect ourselves, to procreate, etc. Dreams, on the other hand, were widely discussed, being considered either as an important step in consolidation of learning or simply the conscious identification of functional patterns derived from the configuration of released or revoked memorized information.

Sexual behavior in sleep, sleepwalking and possible REM behavior disorder: a case report.

Seven cases of sexual behavior during sleep (SBS) have been recently reported. The subjects had histories of behavioral parasomnias as well as positive family histories of parasomnia. A 27 year-old man with a history of sexual behavior during sleep was reported. His sleep history disclosed sleepwalking (SW) since 9 years of age. He also developed episodes of highly disruptive and violent nocturnal behavior with dream enactment at age 20 years, which often resulted in physical injuries either to himself or his wife and infant. His wife also reported episodes of amnestic sexual behavior that began 4 years before referral. During the episodes, the patient typically procured his wife, achieving complete sexual intercourse with total amnesia. Physical and neurological diagnostic workups were unremarkable. Family history disclosed sleepwalking in his brother. He was put on 2mg/day of bedtime clonazepam with a remarkable clinical improvement. This case involves either the combination of violent and non-violent sleepwalking with SBS, or the superimposition of presumed REM sleep behavior disorder (RBD) on top of preexisting SW in a man who also developed SBS in adulthood. Thus, this is a case report of probable parasomnia overlap syndrome.

Jactatio capitis nocturna with persistence in adulthood. Case report.

Rhythmic movement disorder, also known as jactatio capitis nocturna, is an infancy and childhood sleep-related disorder characterized by repetitive movements occurring immediately prior to sleep onset and sustained into light sleep. We report a 19-year-old man with a history of headbanging and repetitive bodyrocking since infancy, occurring on a daily basis at sleep onset. He was born a premature baby but psychomotor milestones were unremarkable. Physical and neurological diagnostic workups were unremarkable. A hospital-based sleep study showed: total sleep time: 178 min; sleep efficiency index 35.8; sleep latency 65 min; REM latency 189 min. There were no respiratory events and head movements occurred at 4/min during wakefulness, stages 1 and 2 NREM sleep. No tonic or phasic electromyographic abnormalities were recorded during REM sleep. A clinical diagnosis of rhythmic movement disorder was performed on the basis of the clinical and sleep studies data. Clonazepam (0.5 mg/day) and midazolam (15 mg/day) yielded no clinical improvement. Imipramine (10 mg/day) produced good clinical outcome. In summary, we report a RMD case with atypical clinical and therapeutical features.

Pontine tegmentum hematoma. Report of a case with pure hemiplegia.

The authors report the case of a 50 year-old hypertensive male patient with a pontine hematoma. The clinical presentation was characterized by pure pyramidal deficit signs (no other signs or symptoms were present). A pure hemiplegia syndrome, although common in supratentorial lesions, is considered to be a rare event in pontine vascular lesions. The pathophysiologic mechanisms of these neurological findings are unclear. The exclusive involvement of the pyramidal tract in this case is likely due to a variation in the vascular anatomy of the pons but, in some cases, a vascular malformation may be the cause.

Epworth Sleepiness Scale outcome in 616 Brazilian medical students.

The Epworth Sleepiness Scale (ESS) measures daytime sleepiness in adults. This paper reports the following data in 616 medical students: 1-ESS scores, 2-its correlation with the declared night sleep time, 3-comparison with ESS values obtained from Australia, 4-comparison of ESS values in a sub-population of 111 students tested early and late 1995. There were 387 males, 185 females and 4 not specified. Age = 20.16 +/- 2.23 (SD), ESS score = 10.00 +/- 3.69 (SD), declared sleep time = 7.04 +/- 1.03 (SD). ESS scores did not statistically correlate with sleep time. Average ESS score was statistically higher than in the Australian sample. Retesting of the medical students showed an increase in ESS values from March to November 1995. Sleep time difference was non-significant. Higher ESS scores in this sample seem to be related to shorter sleep time, but fatigue effects can not be ruled out.

Excessive somnolence.

Excessive somnolence can be quite a incapacitating manifestation, and is frequently neglected by physicians and patients. This article reviews the determinant factors, the evaluation and quantification of diurnal somnolence, and the description and treatment of the main causes of excessive somnolence.

Mandibular-Lingual Repositioning Device--MLRD: preliminary results of 8 patients with obstructive sleep apnea syndrome--OSAS.

Dental devices have been employed in the treatment of snoring and obstructive sleep apnea syndrome (OSAS) of mild to moderate degrees. The authors disclose the preliminary results in 8 patients with clinically diagnosed obstructive sleep apnea polisomnographically confirmed and treated with a dental device (Mandibular-Lingual Repositioning Device--MLRD) developed by one of the authors (RCB). Cephalometrics was performed before usage of MLRD, Epworth Sleepiness Scale (ESS) tests were conducted before and after the MLRD and a questionnaire that subjectively qualified the Overall Subjective Improvement of the patient (OSI) was filled out. The tests were repeated 4 weeks after the application of the MLRD. The average subjective overall improvement was 73.75% and the Epworth Sleepiness Scale was 13.88 (pre-MLRD) and 6.63 (post-MLRD) representing a significant statistical variation (p = 0.05). The authors discuss probable factors involved in the improvement of the subjective measurements of excessive sleepiness.

Sleep-related laryngospasm.

Seven patients (mean age 46.6; range 33-58; 6M,1F) presented with sleep-related choking episodes and were found to have features in common that distinguished them from other known causes of choking episodes during sleep. The characteristic features include: an awakening from sleep with an acute choking sensation, stridor, panic, tachycardia, short duration of episode (less than 60 seconds), infrequent episodes (typically less than 1 per month), and absence of any known etiology. The disorder most commonly occurs in middle-aged males who are otherwise healthy. In one patient an episode of laryngospasm was polysomnographically documented to occur during stage 3. The clinical features and the polysomnographic findings suggest spasm of the vocal cords of unknown etiology.

Neurological complications of coronary arteriography.

The authors report a 46 year-old female who was submitted to a right femoral artery coronary arteriography. During the procedure she presented an upward, downward and convergence gaze paresis; an upbeating nystagmus. A NMRI showed a change in T-2 weighted signal of the left paramedian mesencephalic region. A diagnosis of stroke was made and dextran 40 was prescribed. Vertical gaze paresis progressively disappeared. Convergence paresis and nystagmus improved partially only. The possible pathophysiological basis underlying this clinical picture are: catheter-induced dislodgement of an atheromatous plaque; small thrombi formation and release from the catheter tip; catheter-induced vascular lesion with subsequent thromboembolism or dissection of the intima; cardiac arrhythmia; catheter-induced or contrast medium-induced arterial spasm; a combination of two or more of these.

Yawning.

The ubiquitousness of normal yawning and the existence of abnormal yawning warrant an understanding of this reflex. Its mechanisms and functional role are not entirely known. A review of the literature reveals that yawning is a brain stem arousal reflex with both peripheral and central loops subserving reversal of brain hypoxia or hypoxemia. Behaviorally, yawning is a semi-involuntary act that occurs also because of loss of interest in the surroundings and it is not necessarily associated with fatigue. Socio-environmental factors can influence the emergence of yawning. Dopaminergic, acetylcholinergic, ACTHergic and oxytocinergic systems are involved in the generation and modulation of yawning in animal experimentation.

Nocturnal eating syndrome: a case report with therapeutic response to dexfenfluramine.

A woman with nocturnal eating syndrome responsive to dexfenfluramine (DXF) is reported. Eating consisted of nightly ingestion of large amounts of high-calorie meals and often sloppy meal consumption or preparation. Amnesia for the episodes was total. Anorexigenic medications produced partial control of her daytime carbohydrate craving and no nocturnal eating change. DXF stopped her eating behavior completely. Nocturnal eating herein meets all 4 DSM-III-R diagnostic criteria for binge eating disorder. 5-HT role in neural process controlling sleep-wakefulness (SW) has been widely shown. A 5-HT agonist like DXF could determine changes in the SW processes producing the therapeutic outcome reported herein. However, a specific DXF effect on the behavioral control of carbohydrate ingestion can not be dismissed.

Short-term triazolam use improves nocturnal sleep of narcoleptics.

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 polysomnographic 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 short-term 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.

Eating epilepsy.

Eating epilepsy is a rare type of reflex epilepsy. A 24 years-old male with eating reflex complex partial seizures was submitted to clinical, neurological, neuroradiological and EEG studies. Neurologic and CT examinations were normal. EEG recordings including video-EEG monitoring during meals disclosed focal abnormalities related to both temporal lobes prevailing at the left side and secondary bilateral synchrony mainly in more anterior regions. Ictal findings were similar to the interictal secondary bilateral synchrony except for its longer duration. PB, VPA and DPH monotherapies were ineffective. High dose CBZ monotherapy yielded good but incomplete seizure control. Since a big number of precipitants could be involved, no specific physiopathological basis could be established.

Eating epilepsy

A epilepsia reflexa ao comer é uma rara de epilepsia reflexa. Um paciente de 24 anos com crises parciais complexas reflexas ao comer foi submetido a avaliaçöes clínica, neurológica neurorradiológica e eletrencefalográfica. O exame neurológico e a tomografia de crânio foram normais. Registros de EEG, incluindo menitorizaçäo vídeo-EEG durante a refeiçäo, mostraram presença de anormalidades focais relacionadas a ambos os lobos temporais, predominando à esquerda, e sincronia bilateral secundária, predominando em regiöes anteriores. Os achados ictais säo semelhantes à sincronia bilateral secundária interictal exceto por sua maior duraçäo. Monoterapias com PB, DPH e VPA näo surtiram efeito. Monoterapia com altas doses de CBZ trouxe bons resultados porém com controle incompleto das crises. Como grande número de fatores precipitantes estava potencialmente envolvido, näo foi possível determinar com precisäo a base fisiopatológica das crises reflexas neste caso

Shy-Drager syndrome: a case report with polysomnography.

The authors report a case of Shy-Drager syndrome in a 53 year-old male patient. Autonomic failure was made evident by physical examination as well as laboratory tests. A sleep recording showed decreased percentage of REM sleep and apneas of the central type. The possible mechanisms for this sleep disorder are discussed.

Non-epileptic myoclonus and mitochondrial encephalomyopathy.

Two brothers presented to us with a progressive myoclonic syndrome with slight cerebellar symptoms. Neurological examination disclosed moderate cerebellar signs and pale optic discs; asymmetric, asynchronous and arrhythmic myoclonus, an arrthesthesic deficit and no muscular weakness. EEG background activity was moderately slow with no irritative discharges. CT was normal in both cases. Intermittent photic stimulation increased the frequency of the myoclonic jerks, which became bilateral and synchronous, progressing to a generalized tonic-clonic seizure. EPs and MRI in one case were normal. Anticonvulsant drugs were ineffective. The diagnosis of mitochondrial encephalomyopathy was based on the finding, in muscle specimens, of thickened basement membranes with myofibrillary degeneration and increased number of mitochondria peripherally distributed and with a dense granular matrix and some vacuoles. The clinical and EEG data suggest a subcortical origin for this type of myoclonic syndrome.

Non-epileptic myclonus and mitochondrial encephalomyopathy

Foram examinados dois irmäos portadores de uma síndrome miclónica progressiva comn discretos sintomas cerebelares. O exame neurológico mostrava sinais cerebelares moderados e papilas pálidas; mioclonais assíncronas, arrítmicas e assimétricas, um déficit artrestésico e ausência de fraqueza muscular. A atividade de base do EEG era moderadamente lenta e sem atividade irritativa. A TC era normal em ambos os casos. A estimulaçäo fótica intemitente aumentava a freqüência dos abalos mioclônicos que se tornavam bilaterais e sincronos, progredindo para uma crise tônico-clônica generalizada. Potenciais evocados e RMN em um caso foram normais . Drogas anticonvulsivantes foram ineficazes no controle das mioclonias. O diagníostico de encefalomiopatia mitocondrial foi realizado através do achado em espécimes musculares de membranas basais espessadas, com degeneraçäo miofibrilar e um número elevado de mitocondrias distribuídos perifericamente e com uma matriz densa, granular e com alguns vacúolos. Os achados clínicos e eletrográficos sugerem uma origem subcortical para esta síndrome mioclônica