Narcolepsy Research Articles

Transient Rebound of Cataplexy After Anticataplectic Medication Withdrawal

Antidepressant medications — tricyclic antidepressants (TCAs), nonselective serotonin reuptake inhibitors (NSRIs), or selective serotonin reuptake inhibitors (SSRIs) — are often prescribed to treat cataplexy in patients with narcolepsy. Now, researcher have conduced a post hoc study to address the issue of rebound cataplexy associated with the withdrawal of antidepressants used for cataplexy. The participants were patients who had been enrolled in a trial of sodium oxybate for cataplexy and required discontinuation …

Narcolepsy an often missed diagnosis: First documented case from India

Narcolepsy an often missed diagnosis: First documented case from India

Narcolepsy: How common is the tetrad?

Narcolepsy: How common is the tetrad?

Sympathetic and cardiovascular activity during cataplexy in narcolepsy

Autonomic nervous system activity changes have been described during cataplexy as playing a role in triggering it. To confirm these previous findings, we investigated the time course of sympathetic and cardiovascular activities during cataplexy. We made for the first time microneurographic recordings of 10 cataplectic episodes in three patients with hypocretin-deficient narcolepsy. During microneurography, muscle sympathetic nerve activity (MSNA) was recorded simultaneously with heart rate (HR), respiratory movements, arterial finger blood pressure (BP), electroencephalography, electro-oculogram and superficial electromyogram. Results showed no significant autonomic changes before the onset of the cataplectic episodes. Cataplexy was associated with a significant increase in MSNA and BP compared with baseline, whereas HR was markedly decreased. An irregular breathing pattern mainly characterized by apnea typically occurred during the attacks. In conclusion, our findings did not show significant changes in autonomic activity prior to cataplexy onset, ruling out a triggering role of the autonomic system. However, cataplexy was associated with co-activation of sympathetic and parasympathetic autonomic systems, a pattern reminiscent of that reported during the vigilance reaction in animals.

Activation of serotonin 5-HT 1-receptors decreased gripping-induced immobility episodes in taiep rats

The taiep rat is a myelin mutant that shows a disorganized sleep–wake cycle and immobility episodes (IEs) when the animals are gripped at the base of the tail. During IEs electroencephalographic recordings show a rapid eye movement (REM) sleep-like pattern. These alterations are quite similar to those reported in narcolepsy–cataplexy. Pharmacologically, systemic administration of α 2 adrenoceptor agonists increases gripping-induced IEs, whereas α 2 antagonists decrease them. However prazosin, an α 1 antagonist, increases gripping-induced IEs. In male 8-month-old taiep rats we have studied the effect of systemic administration of serotonergic autoreceptor agonists and antagonists on gripping-induced IEs. 8-Hydroxy-2-(di- n-propylamino) tetraline hydrobromide (8-OH-DPAT), a 5-HT 1A agonist, and 3-trifluoromethylphenylpiperazine hydrochloride (TFMPP), a 5-HT 1B agonist, produce a significant decrease in the frequency and mean duration of IEs. Systemic administration of spiperone and 1-(2-methoxyphenyl)-4[4-(2-phthalimido) butyl]piperazine hydrobromide (NAN-190), 5-HT 1 antagonists, increase IEs and their mean duration. When the specific serotonin antagonist N-[2[4-(2-methoxyphenyl)-1-piperazinyl]ethyl]- N-2-pyridinyl-cyclohexanecarboxamide maleate (WAY 100635, 100 μg/kg) was injected 15 min before 8-OH-DPAT, this specific antagonist reverses the effects caused by the 5-HT 1A agonist. These results show that serotonergic 5-HT 1-receptors are involved in the susceptibility of gripping-induced IEs in taiep rats. Similar results have been reported in the food-elicited cataplexy test in narcoleptic dogs.

Reported Accidents in Narcolepsy

Reported Accidents in Narcolepsy

Learning Style Preferences of Persons with Narcolepsy

Learning Style Preferences of Persons with Narcolepsy

The Legal Aspects of Narcolepsy

The Legal Aspects of Narcolepsy

Self-Esteem in Persons with Narcolepsy

(1992). Self-Esteem in Persons with Narcolepsy. Loss, Grief & Care: Vol. 5, No. 3-4, pp. 45-51.

Psychosocial Aspects of Narcolepsy in Children and Adolescents

Psychosocial Aspects of Narcolepsy in Children and Adolescents

Can We Predict Cognitive Impairments in Persons with Narcolepsy

Can We Predict Cognitive Impairments in Persons with Narcolepsy

Story-like organization of REM-dreams in patients with narcolepsy–cataplexy

Narcolepsy with cataplexy (NC) is a neurological disorder characterized by excessive daytime sleepiness and an altered architecture of sleep. Previous laboratory studies have shown that frightening, bizarre and visually vivid contents are more frequent in dream experiences developed during the first period of REM sleep by NC patients than healthy subjects. As the structural organization of dream experiences of NC patients has not been yet examined, we compared its indicators in dream reports collected from a sample of NC patients and their matched controls. During an experimental night two awakenings were provoked after 8 min of REM sleep in the first and third sleep cycle. Dream reports were analyzed using the rules of story grammars, capable of identifying units larger than single contents and describing their story-like organization. While dream recall (about 85%) was comparable in NC patients and controls, 1st-REM dream reports were longer in NC patients. Statistical analyses on the 12 NC patients and their matched controls who reported dreams after both REM periods showed that dream experiences occurring in 1st-REM reports of NC patients were longer and had a more complex organization than those of controls. These findings suggest that the cognitive processes underlying dream generation reach their optimal functioning earlier in the night in NC patients than in normal subjects.

S.03.01 The neurobiology of hypocretins/orexins in narcolepsy and arousal

S.03.01 The neurobiology of hypocretins/orexins in narcolepsy and arousal

Challenging Sleep Homeostasis in Narcolepsy-Cataplexy: Implications for Non-REM and REM Sleep Regulation

We recently proposed insufficient non-rapid eye movement sleep (NREMS) intensity to contribute to disturbed nocturnal sleep in patients with narcolepsy-cataplexy (NC). To test this hypothesis, we investigated the effect of physiologically intensified NREMS in recovery sleep following sleep deprivation. Nocturnal baseline and recovery sleep architecture, and the sleep electroencephalogram (EEG) before and after 40 hours of sustained wakefulness were compared between 6 drug-free patients with NC (age range: 19-37 years) and 6 individually matched, healthy control subjects (18-43 years). Sleep and sleep EEG power spectra (C3A2 derivation). The dynamics of the homeostatic Process S were estimated from the time course of slow-wave activity (SWA, spectral power within 0.75-4.5 Hz) across consecutive NREMS episodes. Sleep research laboratory. In baseline, SWA decreased across consecutive NREMS episodes in patients with NC and control subjects. The build-up of SWA, however, was attenuated in NC in the second episode (P = 0.01) due to a higher number of short wake periods (P = 0.02). Prolonged wakefulness increased initial SWA in both groups (P = 0.003) and normalized the baseline differences between patients and control subjects in the time course of SWA in NREMS. The changed dynamics of SWA in the patients in recovery sleep when compared with baseline were associated with reduced numbers of intermittent wake periods in the first (P = 0.01) and second (P = 0.04) NREMS episodes. All patients, but no control subjects, showed a sleep-onset rapid eye movement period (SOREMP) in both baseline and recovery sleep. Sleep deprivation increased SOREMP duration (P = 0.03). Increased SWA after sleep deprivation indicates that sleep homeostasis is functional in NC. Increased NREMS intensity in recovery sleep postpones sleep fragmentation, supporting our concept that sleep fragmentation is directly related to insufficient NREMS intensity in NC. The persistence of SOREMP despite enhanced NREMS pressure suggests an abnormal interaction between NREMS and REMS regulatory processes.

WO05 Sympathetic and cardiovascular activity during cataplexy in narcolepsy

WO05 Sympathetic and cardiovascular activity during cataplexy in narcolepsy

Agenesis of the corpus callosum associated with narcolepsy–cataplexy

We describe a 24-year-old man with episodes of intense desire to sleep for periods ranging from 2 min to 3 h, episodes of generalized weakness and inability to speak without alteration of consciousness, frequent hypnagogic hallucinations during sleep and occasionally transient paralysis of limbs upon awakening. Brain MRI demonstrated elevation of the third ventricle, a characteristic lack of depiction of the corpus callosum and extension of the bihemispheric fissure to the third ventricle. We assume that structural changes of the base of frontal lobes, diencephalon and brainstem, can be accountable for symptomatic narcolepsy and cataplexy.

New Guidelines on the Treatment of Excessive Sleepiness

The American Academy of Sleep Medicine (AASM) has produced new guidelines on the treatment of narcolepsy and of other hypersomnias of central origin, based on a comprehensive review of the literature. These guidelines are an update of the AASM guidelines on narcolepsy from 2000. The review emphasizes the importance of obtaining an accurate diagnosis by considering the differential diagnosis of disorders of excessive sleepiness. In recent years, important advances have been made in our understanding of the pathophysiology of narcolepsy and in treatment …

Suppression of Motor Evoked Potential and H-reflex during Cataplexy in Narcolepsy

Suppression of Motor Evoked Potential and H-reflex during Cataplexy in Narcolepsy Sun Jung Han, MD, Eun Yeon Joo, MD, Sun Hwa Kim, So-Hee Jung, RN, Seung Bong Hong, MD Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea Department of Neurology, Sanbon Medical Center, College of Medicine, Wonkwang University, Gyeonggi-do, Korea Clinical Trial Center, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea

Characterization of Sleep in Zebrafish and Insomnia in Hypocretin Receptor Mutants

Sleep is a fundamental biological process conserved across the animal kingdom. The study of how sleep regulatory networks are conserved is needed to better understand sleep across evolution. We present a detailed description of a sleep state in adult zebrafish characterized by reversible periods of immobility, increased arousal threshold, and place preference. Rest deprivation using gentle electrical stimulation is followed by a sleep rebound, indicating homeostatic regulation. In contrast to mammals and similarly to birds, light suppresses sleep in zebrafish, with no evidence for a sleep rebound. We also identify a null mutation in the sole receptor for the wake-promoting neuropeptide hypocretin (orexin) in zebrafish. Fish lacking this receptor demonstrate short and fragmented sleep in the dark, in striking contrast to the excessive sleepiness and cataplexy of narcolepsy in mammals. Consistent with this observation, we find that the hypocretin receptor does not colocalize with known major wake-promoting monoaminergic and cholinergic cell groups in the zebrafish. Instead, it colocalizes with large populations of GABAergic neurons, including a subpopulation of Adra2a-positive GABAergic cells in the anterior hypothalamic area, neurons that could assume a sleep modulatory role. Our study validates the use of zebrafish for the study of sleep and indicates molecular diversity in sleep regulatory networks across vertebrates.

PHO04 Narcolepsy in childhood

PHO04 Narcolepsy in childhood