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PubMed2006

Cataplexy leading to the diagnosis of Niemann-Pick disease type C.

Cataplexy in childhood is a rare and often misdiagnosed symptom. It is described as a brief episode of bilateral loss of muscle tone with intact consciousness, triggered by a variety of strong emotions and in particular with unexpected laughter. This report presents a 9-year old male with progressive cerebellar and pyramidal symptoms and a cognitive decline since the age of 4. His recently developed "drop attacks" on laughter were recognized as cataplexy and led to the diagnosis of Niemann-Pick type C disease. With biochemical studies this diagnosis, a lysosomal storage disease, was confirmed. With cataplexy narcolepsy, Niemann-Pick type C disease, Norrie disease, Prader-Willi syndrome, and Coffin-Lowry syndrome are associated disorders. Recognition of cataplexy in children with concomitant neurologic symptoms may lead to an early and straight diagnosis of one of these disorders.

Cataplexy↗

PubMed2004

Cataplexy-active neurons in the hypothalamus: implications for the role of histamine in sleep and waking behavior.

Noradrenergic, serotonergic, and histaminergic neurons are continuously active during waking, reduce discharge during NREM sleep, and cease discharge during REM sleep. Cataplexy, a symptom associated with narcolepsy, is a waking state in which muscle tone is lost, as it is in REM sleep, while environmental awareness continues, as in alert waking. In prior work, we reported that, during cataplexy, noradrenergic neurons cease discharge, and serotonergic neurons greatly reduce activity. We now report that, in contrast to these other monoaminergic "REM-off" cell groups, histamine neurons are active in cataplexy at a level similar to or greater than that in quiet waking. We hypothesize that the activity of histamine cells is linked to the maintenance of waking, in contrast to activity in noradrenergic and serotonergic neurons, which is more tightly coupled to the maintenance of muscle tone in waking and its loss in REM sleep and cataplexy.

Action Potentials↗

PubMed2002

Analysis of onset location, laterality and propagation of cataplexy in canine narcolepsy.

Hypocretin deficiency is involved in most cases of human narcolepsy. Although cataplexy is pathognomonic of narcolepsy, mechanisms of induction of cataplexy are largely unknown. Patterns of occurrence of cataplectic attacks (i.e. onset location, laterality, and propagation of attacks) in hypocretin receptor 2-mutated narcoleptic Dobermans were characterized in order to understand the basic mechanism of this abnormal sleep-related atonia. Most cataplexy attacks were bilateral (98%) and were initiated in the hind legs (80%). Progression of attacks was also seen (49%) and atonia during propagation was most often bilateral (94%). Involvement of abnormal inactivation of bilateral pathways to the spinal motoneurones due to a deficiency in hypocretin neurotransmission is suggested in the occurrence of cataplexy.

Animals↗

PubMedDate not supplied

[Cataplexy in type C Niemann-Pick disease].

Cataplexy usually occurs as a part of the tetrad of clinical phenomena of idiopathic narcolepsy. Symptomatic cases are rare. A 4 years old girl from consangineous parents had recurrent loss of muscle tone and fell to the ground, when she laughed. The EEG was normal. Prolonged neonatal jaundice with cholestasis, hepatosplenomegaly, mental regression, supranuclear ophthalmoplegia, and foam cells led to the diagnosis of Niemann-Pick disease type C with symptomatic cataplexy. Symptomatic forms of the narcolepsy-cataplexy complex should be considered, when there is an early onset before puberty, cataplectic attacks predominate the narcoleptic attacks, and when additional neurological symptoms occur. Symptomatic cataplexy occurs in Niemann-Pick disease type C. It is considered to be the result of lesions of the pontine reticular formation.

Astrocytes↗

PubMed1989

Exacerbation of human cataplexy by prazosin.

A middle-aged woman with narcolepsy developed a pronounced exacerbation of cataplexy within 3 days of beginning treatment for hypertension with prazosin, an alpha 1-adrenoceptor antagonist. At times, episodes of cataplexy were virtually continuous (status cataplecticus), and there was only partial amelioration with tricyclic antidepressants. Cataplexy improved when prazosin was discontinued. These findings are similar to the reported effects of prazosin on cataplexy in narcoleptic dogs; they support a role for altered alpha 1-adrenoceptor function in narcolepsy.

Cataplexy↗

PubMed1993

Desmethyl metabolites of serotonergic uptake inhibitors are more potent for suppressing canine cataplexy than their parent compounds.

Our series of pharmacological studies on canine narcolepsy has suggested that the adrenergic systems are more critically involved in the regulation of cataplexy than the serotonergic and dopaminergic systems. This, however, is an apparent contradiction to data obtained in human patients, which show that chronic oral administration of serotonergic uptake inhibitors, such as clomipramine, zimelidine and fluoxetine, is effective in reducing cataplexy. To explore this discrepancy, we have assessed the anticataplectic effects of various serotonergic uptake inhibitors and their active desmethyl metabolites on canine cataplexy. We found that the anticataplectic effect of the desmethyl metabolites, which are usually more potent for in vitro adrenergic uptake inhibition, was more potent and developed more rapidly than the effect of the parent compounds. Furthermore, the anticataplectic potency was positively correlated to the adrenergic uptake inhibition and was negatively correlated with serotonergic uptake inhibition among the 10 compounds tested. These results are consistent with our hypothesis of a preferential involvement of the adrenergic system in the control of cataplexy. Our results also suggest that the anticataplectic effect of "selective" serotonergic uptake inhibitors in human narcolepsy might be mediated by their less selective active metabolites.

Analysis of Variance↗

PubMed1994

Motor-evoked responses to transcranial brain stimulation persist during cataplexy: a case report.

Magnetic brain stimulation was performed in a patient with the narcolepsy-cataplexy syndrome during and after a cataplectic status. Amplitudes and thresholds of responses in six muscles (diaphragm, lumbar erector spinae, trapezius, biceps, tibialis anterior and abductor digiti V) remained unchanged during cataplexy as compared to the normal state. Our data suggest that, similar to rapid eye movement (REM) sleep, an enhanced cortical excitability to magnetic brain stimulation may compensate for the postsynaptic spinal inhibition of muscle tone during cataplexy, and that there is no difference in this respect between axial and distal muscles. Our data agree well with other evidence of increased cortex activity during cataplexy and REM sleep.

Action Potentials↗

PubMed1997

Familial aspects of narcolepsy-cataplexy in the Czech Republic.

A group of 153 probands with narcolepsy included 38 subjects (24.8%) with a familial incidence of excessive daytime sleepiness (EDS). In 15 cases (9.8%), at least one additional family member suffered from narcolepsy-cataplexy; only EDS was present in the remaining 23 cases (15.0%). One thousand eighty-two relatives were evaluated. The percentage of first degree relatives affected with narcolepsy-cataplexy was 2.28% (1.20% if only clinically confirmed cases were accounted); the adequate value for second degree relatives was 1.49%. The occurrence of EDS exceeded these values several times (4.28% in first degree relatives, 6.57% in second degree relatives). The vertical mode of transmission was found in most families. Human leukocyte antigen (HLA) typing was performed in six families with multiple-case incidence of narcolepsy. Forty-one blood samples were analyzed (12 patients with narcolepsy, 7 with only EDS, 2 with sleep apnea syndrome, and 20 healthy relatives). HLA DR2+ and DQB1*0602+ were found in only 8 out of 12 narcoleptic patients with cataplexy and in six out of seven patients with isolated attacks of sleepiness. These findings support the hypothesis that there is a common genetic basis for narcolepsy associated with cataplexy and "monosymptomatic" forms of narcolepsy and suggest the existence of non-major histocompatibility complex (MHC) susceptibility factors for narcolepsy.

Adolescent↗

PubMed1986

Serotoninergic reuptake mechanisms in the control of cataplexy.

Zimelidine, a selective inhibitor of serotonin (5-HT) reuptake in the CNS, was administered to narcoleptic patients. This medication has a potent anticataplectic action without improving daytime somnolence. These results suggest that 5-HT neuronal systems are involved in the physiopathology of cataplexy. Zimelidine, however, has no anticholinergic effect, so it is unlikely that cholinergic mechanisms thought to be important in animal cataplexy would play a major role in human cataplexy. In addition, zimelidine had no effect on nocturnal sleep patterns of these patients which is surprising considering the importance of 5-HT neuronal systems in sleep physiology. A 5-HT hypothesis of cataplexy is formulated, and the mechanisms of action of other anticataplectic agents are discussed.

Adult↗

PubMed2004

Corticospinal excitability during laughter: implications for cataplexy and the comparison with REM sleep atonia.

Cataplexy is usually seen as rapid eye movement (REM) sleep atonia occurring at an inopportune moment. REM sleep atonia is the result of postsynaptic inhibition, i.e. inhibition of alpha motor neurones. Although this may explain the suppression of H-reflexes during REM sleep, cataplexy and laughter, it is not the only explanation. Presynaptic inhibition, in which afferent impulses are prevented from reaching motor neurones, is an alternative. Testing H-reflexes and magnetic-evoked potentials (MEPs) helps to tell them apart: in postsynaptic inhibition MEPs and H-reflexes change in tandem, while H-reflexes may decrease independent of MEPs with other inhibition modes. We studied motor inhibition during laughter, the strongest trigger for cataplexy. H-reflexes were evoked every 2 s in the soleus muscle in 10 healthy subjects watching comical video fragments. MEPs were evoked when H-reflexes decreased during laughter, and, as a control, when subjects did not laugh. Pairs of MEPs and the immediately preceding H-reflexes were studied. Compared with the control condition, laughter caused mean MEP area to increase by 60% (P=0.006) and mean H-reflex amplitude to decrease by 33% (P=0.008). This pattern proves that postsynaptic inhibition cannot have been the sole influence. The findings do not prove which mechanisms are involved; one possibility is that the decrease in H-reflex amplitude was the result of presynaptic inhibition, and that cortical and/or spinal facilitation accounted for increased MEPs. Regardless, the pattern differs fundamentally from the reported mechanism of REM sleep atonia. Existing scanty data on cataplexy suggest a pattern of H-reflexes and MEPs similar to that during laughter, but this needs further study.

Arousal↗

PubMed2006

Hypocretin (orexin) deficiency predicts severe objective excessive daytime sleepiness in narcolepsy with cataplexy.

Cerebrospinal fluid (CSF) hypocretin-1 deficiency is associated with definite ("clear cut") cataplexy in patients with narcolepsy. The relationship between CSF hypocretin-1 levels and other narcoleptic symptoms (including excessive daytime sleepiness, EDS) is not properly understood. In a consecutive series of 18 subjects with narcolepsy and definite cataplexy, patients with undetectable CSF hypocretin-1 (n = 12) were found to have significantly lower mean sleep latencies (p = 0.045) and a higher frequency of sleep onset REM periods (SOREMPs, p = 0.025) on multiple sleep latency test than patients (n = 6) with detectable levels. Conversely, Epworth sleepiness scale scores, the frequency of hallucinations/sleep paralysis, and the frequency and severity of cataplexy were similar in both groups. These results suggest that hypocretin deficiency identifies a homogenous group of patients with narcolepsy characterised by the presence of definite cataplexy, severe EDS, and frequent SOREMPs.

Adolescent↗

PubMed2006

Cerebral perfusion changes during cataplexy in narcolepsy patients.

To localize cerebral perfusion differences during cataplexy, brain SPECT subtraction was performed between cataplexy and baseline awake period or REM sleep in patients with narcolepsy. During cataplexy, subtracted SPECT showed hyperperfusion in right amygdala, bilateral cingulate gyri, basal ganglia, thalami, premotor cortices, sensorimotor cortices, right insula, and brainstem, and hypoperfusion in prefrontal cortex and occipital lobe. This result suggests that cataplexy is produced by the activation of amygdalo-cortico-basal ganglia-brainstem circuit.

Blood Flow Velocity↗

PubMed1980

Continuous cataplexy in a patient with a midbrain tumor: the limp man syndrome.

A patient with glioblastoma of the rostral brainstem and hypothalamus exhibited bilateral internuclear ophthalmoplegia and vertical nystagmus; he suffered episodes of cataplexy, narcolepsy, and sleep paralysis. A peculiar fluctuation of posture and tone ("limp man syndrome") proved to be a manifestation of continuous cataplexy, as documented by H-reflex recordings. This is the first report of a remarkable movement disorder caused by continuous, fluctuating, partial cataplexy, and is the second report of an association between cataplexy and a tumor of the rostral brainstem.

Adult↗

PubMed1996

Cataplexy and monoamine oxidase deficiency in Norrie disease.

Norrie disease (ND) is an X-linked recessive disorder causing ocular atrophy, mental retardation, deafness, and dysmorphic features. Virtually absent monoamine oxidase (MAO) type-A and -B activity has been found in some boys with chromosome deletions. We report the coexistence of cataplexy and abnormal REM sleep organization with ND. Three related boys, referred for treatment of medically refractory atonic spells and apneas, underwent extended EEG-video-polysomnographic monitoring. They demonstrated attacks of cataplexy and inappropriate periods of REM sleep during which they were unarousable. One boy also had generalized tonic-clonic seizures. Previous testing revealed that all three have complete ND gene deletions. In all subjects, platelet MAO-B activity was absent, serum serotonin levels were markedly increased, and plasma catecholamine levels were normal. Data from the canine narcolepsy syndrome model implicate abnormal catecholaminergic and cholinergic activities in the pathogenesis of cataplexy. Our findings suggest that abnormal MAO activity or an imbalance between serotonin and other neurotransmitter levels may be involved in the pathogenesis of human cataplexy.

Adult↗

PubMed2006

Niemann-Pick disease type C: cataplexy and hypocretin in cerebrospinal fluid.

Niemann-Pick disease type C (NPC) is an inherited lipid storage disorder, characterized by a defect in intracellular trafficking of exogenous cholesterol that leads to the lysosomal accumulation of unesterified cholesterol. We report a Japanese patient with NPC caused by a homozygous c.2974 G > T mutation of the NPC1 gene, which predicts a glycine (GGG) to tryptophan (TGG) change at codon 992 (designated as p.G992W). This is a well-known NPC1 gene mutation that causes a unique phenotype of NPC, which has been limited to a single Acadian ancestor in Nova Scotia, Canada. Our patient characteristically started presenting with cataplexy at the age of 9 years. Recent studies have shown reduced hypocretin-1 levels in the cerebrospinal fluid (CSF) of narcoleptic patients with cataplexy. In our patient, the level of hypocretin-1 was determined as moderately low, 174 pg/ml (normal, > 200 pg/ml). To date, CSF levels of hypocretin-1 have been determined by using an identical assay method in 7 cases of NPC, including our case. All of the NPC cases with cataplexy demonstrated low levels of CSF hypocretin-1, confirming the association of reduced CSF hypocretin-1 levels with cataplexy in NPC.

Carrier Proteins↗

PubMed2006

Cataplexy associated with narcolepsy: epidemiology, pathophysiology and management.

Although narcolepsy was first described over 100 years ago, most of what is known about the pathological changes in the CNS that are responsible for this unusual disease has been learned during the past few years. It is now known that narcolepsy is caused by the loss of a relatively few neurons that are responsible for producing the neuropeptide hypocretin in the CNS. The onset of narcolepsy typically occurs in early adulthood and may consist of a variety of symptoms; however, cataplexy (an abrupt, bilateral loss of skeletal muscle tone) is most specific to narcolepsy. TCAs were found to be beneficial for the treatment of cataplexy over 40 years ago and, more recently, the SSRIs have been used to treat the condition. The recent availability of sodium oxybate (the first drug to receive regulatory approval for the treatment of cataplexy) represents a significant advance in the treatment of narcolepsy, as it is highly efficacious for the treatment of cataplexy and shows promise for the treatment of excessive sleepiness and for improving sleep quality in patients with narcolepsy.

Cataplexy↗

PubMed1995

The pineal gland, cataplexy, and multiple sclerosis.

Since the discovery of melatonin as the principal hormone of the pineal gland in 1963, scientists have come to recognize that melatonin is a "master hormone" involved in the control of circadian rhythms and other biological functions. Although little is known about the influence of the pineal gland on motor control, important clues may be obtained by considering the pattern of melatonin secretion during the sleep cycles and particularly during rapid eye movement (REM) sleep when melatonin plasma levels are at their lowest. Since REM sleep is characterized by the occurrence of profound atonia which results in an almost complete paralysis of striated muscles, it is suggested that there might be a causal relationship between inhibition of melatonin secretion during REM sleep and the development of REM sleep atonia. This relationship is supported by the findings that melatonin regulates the activity of brainstem serotonin (5-HT) neurons which characteristically cease to fire during REM sleep and which faciliate the development of REM sleep atonia. Moreover, as the muscular atonia of REM sleep is physiologically and pharmacologically indistinguishable from cataplexy, it is possible that the pineal gland also influences to the development of cataplexy. Cataplexy is an ancillary symptom of narcolepsy and also occurs in multiple sclerosis (MS). In fact, it is believed that several of the neurological symptoms experienced by patients with MS such as weakness in the legs, feeling of collapsing knees, paroxysmal sudden falling, weakness in the neck, extreme fatigue, intermittent paresthesias, slurring of speech and intermittent blurring of vision, which often are exacerbated by stress and other emotional influences, may reflect the manifestations of cataplexy. Thus, several of the clinical features of MS may reflect a dissociated state of wakefulness and sleep and may improve by the administration of anticataplectic drugs.

Cataplexy↗

PubMed1995

Comparative effects of modafinil and amphetamine on daytime sleepiness and cataplexy of narcoleptic dogs.

The effects of modafinil and amphetamine on daytime sleep (polysomnographic recordings) and cataplexy (the food-elicited cataplexy test) were compared using the narcoleptic canine model. Results indicate that both modafinil (5 and 10 mg/kg body weight i.v.) and amphetamine (100 and 200 micrograms/kg i.v.) increase wakefulness and reduce slow-wave sleep in control and narcoleptic dogs. In contrast, the results of cataplexy testing demonstrate that amphetamine (2.5-160 micrograms/kg i.v.), but not modafinil (0.125-8.0 mg/kg i.v.) significantly suppresses canine cataplexy. These results suggest that the pharmacological property of modafinil is distinct from amphetamine. Results of polysomnographic recordings also demonstrate that narcoleptic dogs slept significantly more during the daytime than control dogs and required very high doses (10 mg/kg i.v. modafinil; 200 micrograms/kg i.v. amphetamine) of stimulants to reduce their level of sleepiness to that of control dogs. This finding is consistent with the data collected in human narcolepsy and validates the use of this canine model for the screening of stimulant compounds.

Amphetamine↗