Phasic muscle activity during REM sleep in infancy-normal maturation and contrastive abnormality in SIDS/ALTE and West syndrome.

The generation of phasic muscle activity during REM sleep is regulated by the brainstem. We proposed two sleep indices for phasic muscle activity during REM sleep, and examine their usefulness in assessing normal brainstem maturation and functional brainstem impairment during infancy. One - the dissociation index (DI) - seems to reflect maturation of the tonic inhibitory system functioning during REM sleep, and the other - % body movements in REMs bursts (%BMs-R) - to reflect that of the phasic one. In normal infants, DI showed a gradual, linear and significant increase with age, whereas %BMs-R showed a gradual and significant decrease with age. In infants with sudden infant death syndrome (SIDS) and one who had experienced apparent life-threatening events (ALTE), the DI values were lower than those in controls, although %BMs-R values were identical in the controls. In contrast, DI was variable in infants with West syndrome (WS), while %BMs-R exceeded normal values. The tonic inhibitory system seemed to be specifically involved in SIDS and ALTE, but the phasic inhibitory one in WS. Anatomical differences between these inhibitory systems are also discussed.

Phasic loss of intercostal muscle activity occurring with rapid eye movements during REM sleep.

We tried to estimate the phasic motor inhibition occurring with rapid eye movements (REMs) during REM sleep in children by means of polysomnography. Phasic inhibition of intercostal muscle activity with REMs has been proved by averaging the integrated surface electromyograms in three children. The average latency from the onset of REMs to this inhibition was 38.0 ms, their average duration being 237.0 ms. We discussed the possibility that the REM-related phasic inhibition obtained here was involved in the brainstem-spinal cord inhibitory system functioning during REM sleep.

Phasic motor activity reduction occurring with horizontal rapid eye movements during REM sleep is disturbed in infantile spasms.

Single polysomnography was performed before treatment in 17 patients with infantile spasms (IS) (13 with a cryptogenic type and 4 with a symptomatic one). Their sleep components during rapid eye movement (REM) sleep were compared with those in 22 age-matched controls. The tonic muscle atonia during REM sleep was observed in all IS patients as in controls. The amount of REM sleep in IS patients was significantly lower, while the incidences of gross movements, phasic chin muscle activity, and bursts of horizontal rapid eye movements were identical with those in controls. The phasic inhibition index (PII), i.e., the rate of simultaneous occurrence of phasic chin muscle activity and bursts of horizontal rapid eye movements, was significantly higher in IS than in controls. The PII value was the only parameter that reflected our patients' prognosis among the obtained REM sleep parameters. We presume that the elevated PII in IS reflects the weakness of the phasic motor activity reduction occurring with horizontal rapid eye movements, and attribute this disturbance to a functional instability of the rostral pontine tegmentum. We propose that PII is a useful parameter for assessing the prognosis of IS. Considering the neural basis for elevated PII in IS, this index is expected to provide a clue for explaining the pathophysiology of IS.

Rapid eye movement sleep in breath holders.

One-night polysomnography was performed on seven subjects suffering from breath-holding spells, including one whose death was suggested to be a consequence of a breath-holding spell. The fatal case showed no rapid eye movements (REMs) during REM sleep, although he exhibited REMs during wakefulness. The average numbers of both REMs and bursts of REMs in REM sleep in the other six breath holders were significantly lower than those in age-matched controls. The breath holders showed no airway obstruction, desaturation, or sleep fragmentation. Since the rapid ocular activity in REM sleep is generated in the brain stem, we hypothesized that a functional brainstem disturbance is involved in the occurrence of breath-holding spells.

Polygraphic features of a victim of sudden infant death syndrome and of infants with apparent life-threatening event.

We analyzed a polygram of a victim of sudden infant death syndrome (SIDS) which had been taken five weeks prior to his death. The findings are discussed in association with the serial polygraphic observations of four infants who had suffered from apparent life-threatening event (ALTE), and twenty neurologically normal infants. Frequencies of respiratory pauses were high in SIDS, and average durations of respiratory pauses showed higher values in ALTE than in the controls. Normal paradoxical motions between chest and abdominal wall during active sleep period (AS) were completely abolished in the records of SIDS and of one ALTE. Normal developmental decreases of localized movements (LMs) on mental muscle with age were insufficient in ALTE. The numbers of twitch movements (TMs) were low in SIDS and in two of ALTE, while those of gross movements in the subjects were identical with those in the controls. Dissociation indexes (ratio of the number of TMs against the sum of the numbers of TMs and LMs) were low in SIDS and in two of ALTE. These findings seemed to be the physiological reflection of the impairment of arousal responsiveness and of the developmental disturbance of the brainstem in SIDS and ALTE. Polygraphic evaluations on the respiratory pattern during AS and the dissociation state of TMs from LMs may be helpful in the early detection of SIDS and/or ALTE in asymptomatic infants.

Brainstem control of phasic muscle activity during REM sleep: a review and hypothesis.

For the generation of phasic muscle activity during rapid eye movement (REM) sleep, strong motor excitation to overcome both tonic and phasic inhibition is needed at the motoneuron level. Descending pathways originating in the rostral pons (cholinoceptive (nucleus reticularis pontis oralis-->nucleus reticularis gigantocellularis, peri-locus coeruleus pars alpha-->nucleus reticularis magnocellularis) and cholinergic (pedunculopontine tegmental nucleus-->nucleus reticularis paramedianus) pathways) are involved in motor inhibition during REM sleep. Since the origins of excitatory drives related to phasic muscle activity during REM sleep are also in the brainstem, the occurrence of phasic muscle activity can be said to be determined by brainstem activity. We review the basic and clinical studies on phasic muscle activity during REM sleep and propose the possibility that it can be a beneficial parameter for assessing brainstem activity, especially in relation to its maturation during early stage of life.

A case of Dandy-Walker malformation: consideration on the teratogenic period and sleep structures.

An 11-month-old girl suffering from Dandy-Walker malformation (DWM) associated with tetralogy of Fallot (TOF) is presented. There has been no report describing a case of DWM associated with TOF. Our case may raise a new discussion on the teratogenic period of these anomalies. A polysomnogram was obtained, and basic sleep components, such as the proportion of each sleep stage and the numbers of body movements and rapid eye movements, showed no significant differences from those in the controls, despite hydrocephalus, pachygyria of the cerebral cortex and a large low density area in the posterior fossa.

REM sleep abnormalities in severe athetoid cerebral palsy.

Various abnormalities of sleep have been reported in extrapyramidal diseases in adults. We have investigated the disturbances of REM sleep (SREM) in severe athetoid cerebral palsy (ACP) originating perinatally. Ten ACP patients, 5 males and 5 females ranging from 15 to 30 years old, were studied by means of all-night polygraphic examination. Three cases showed a marked decrease in rapid eye movements in SREM. Moreover, the tone of submental muscle in SREM was also disturbed in three. Regarding body movements during sleep, gross movements and twitch movements of the submental muscle were analyzed. In most of the patients, an abnormal distribution of body movements according to sleep stages was observed, the rate being significantly reduced in SREM. REMs, atonia and body movements are considered to be related to the brainstem function in animals. The results of the present study suggest that perinatal extrapyramidal diseases could also coincide with brainstem dysfunctions.

Multimodality evoked potentials in severe athetoid cerebral palsy: correlation with clinical features and all-night polygraphical data.

We examined the correlation between the clinical and electrophysiological features, short latency somatosensory evoked potentials (SSEPs), auditory brainstem responses (ABRs), electrically elicited blink reflexes (BRs) and all-night polysomnographical examination (PSG) data in eight patients with severe athetoid cerebral palsy (ACP). Absence ABRs were observed in cases who had suffered from severe neonatal hyperbilirubinemia (posticteric ACP), and in most of them gaze abnormalities and a significant reduction in rapid eye movements during REM sleep, as observed on PSG, coexisted. Prolongation of the interpeak latency, N13-N20, of SSEPs existed concurrently with disturbed late components of BRs in two cases of posticteric ACP. The phasic contractions of the submental muscle during sleep were impaired in most of the patients. Multimodality evoked potentials together with PSGs seem to be useful for assessing brainstem dysfunctions in ACP and might also be of use for elucidating the pathogenesis of the episodic sudden death in ACP.

Mexiletine hydrochloride in an infant with intractable epilepsy.

A female infant with seizures refractory to conventional therapeutic agents was presented. Mexiletine hydrochloride, administered orally, was effective in controlling her seizures. Her sleep structure and psychomotor development seemed to improve after reduction of the fits.

A case of chronic epileptic encephalopathy of neonatal onset. A probable concern of human cytomegalovirus.

A 10-year-old male patient, who had suffered from intractable convulsions from the neonatal period, is presented. Serial brain images suggested slow, gradual destruction of neural elements. Human cytomegalovirus (HCMV) DNA was detected in his cerebrospinal fluid (CSF) by means of the polymerase chain reaction. Intrathecal interferon had a favorable effect on his seizures. We assume a close relationship between HCMV and some chronic types of epileptic encephalitis/encephalopathy.

Sleep study on patients with severe brain damage--polysomnographical examination.

Polysomnograms were obtained for five severely brain damaged patients, and phasic sleep parameters-body movements (BMs) and rapid eye movements (REMs)-were examined. CT scanning of their brains demonstrated large low density areas in the bilateral hemispheres. In the three patients with flat EEG, sleep could only be classified into two stages; one with REMs[R(+)] and one without REMs[R(-)]. In the other two patients, stage R(-) was further classified into two stages according to the EEG findings. Gross movements (GMs) showed a synchronous pattern in all the patients. GMs and low angle REMs decreased in number while twitch movements and high angle REMs showed almost the same incidences as in normal controls. Localized movements showed marked variations among the patients. It was suggested that, except for normal uncoordinated asymmetrical GMs, BMs did not necessarily require higher brain structures for their generation.

Sleep disturbance in children with growth hormone deficiency.

We examined the effects of growth hormone (GH) deficiency on sleep development by performing all-night polysomnography in three female children with GH deficiency (GHD). The percentage of REM sleep seemed to be reduced before the treatment in 2 cases, and human GH (hGH) compensation slightly increased it. Submental twitch movements (mTMs), i.e., body movements during sleep localized in the submental muscle and lasting less than 0.5 seconds, were commonly disturbed in the three patients. Rapid eye movements in REM sleep (REMs) were reduced before the therapy in one case, this decrease being reversed on hGH compensation. REMs also seemed to increase after hGH treatment in the other two cases. Dopamines and cholinergic muscarinic agonists can cause GH release, while mTMs and REMs might be related to dopaminergic and cholinergic systems in the human brain. It is intriguing that GHD, and the disturbance of mTMs and REMs coexisted in children with GHD. Since a relatively poor social outcome in patients with GHD has been reported, even after hGH compensation, it is important to monitor their neurological development by means of evaluation of their sleep disturbance.

Sleep development in children with congenital and acquired hypothyroidism.

To determine how thyroid hormone deficiency before birth influences early development of the human central nervous system, we examined sleep development in children with congenital hypothyroidism using all-night polysomnography. Although the sleep-wakefulness circadian rhythm was not disturbed, two patients under 1 year of age showed mild decreases of REM sleep. Rapid eye movements during REM sleep were significantly decreased in one patient in whom thyroxine replacement was delayed. Regarding phasic body movements during sleep, generalized gross movements were more frequently disturbed than localized muscle twitches, and even after L-thyroxine replacement, they were significantly reduced when compared with those in controls. Children with acquired hypothyroidism and neonatal transient hyperthyrotropinemia showed no severe abnormalities of the sleep parameters examined here. Sleep development in patients with congenital hypothyroidism is believed to be useful for regional evaluation of the brain impairment in congenital hypothyroidism.

Polygraphical study on age dependent epileptic encephalopathy--relationship between body movements during sleep and prognosis.

Body movements (BMs) during sleep in patients with age dependent epileptic encephalopathy (ADEE) were studied polysomnographically in order to clarify the underlying mechanism of intractability and the age dependent trend. Twenty patients were divided into two groups according to the prognosis of convulsions. In the good prognosis group, BMs were nearly normal except for a low frequency in some cases. In the intractable group with seizures which were uncontrollable by medication and recurred within a year, BMs showed abnormalities as follows: abnormal distribution according to sleep stages, and/or a low frequency; increased BMs on therapy with prednisolone or ACTH. Moreover, a paradoxical increase of BMs with age and recurrence of seizures concomitantly occurred in the course of the disease. Status epilepticus appeared in cases under 1-DOPA administration or with a strikingly high frequency of BMs. Since electrophysiological evidence indicates that BMs during sleep are modulated by the dopaminergic (DA) system, the present data might suggest that prognosis of convulsions in ADEE depend upon, at least in part, the DA system. And denervated supersensitivity of that system might give rise to recurrence of seizures and status epilepticus.

Effect of alpha-methyldopa administration during pregnancy on the development of a child's sleep.

A male infant was born to a mother who had been suffering from primary hyperaldosteronism with the administration of alpha-methyldopa (MD) during pregnancy. His behavioral development, especially that of sleep, was studied by means of sleep-awake rhythm and polysomnography recordings (PSG) from 2 months to 2 years and 5 months of age. His daily sleep-awake rhythm showed some abnormal pattern. As to the PSG, the proportion of each sleep stage was normal and the two types of body movements (BM) showed various patterns. A paradoxical increase was seen in the twitch movement of some muscles. MD affects the catecholamine system in the CNS and human sleep. Since the sleep-awake rhythm and BM are thought to be related to the monoaminergic system in the CNS, we assume that his behavior and sleep disorders are the effects of the maternal MD administration during pregnancy.

Phasic sleep components in infants with cyanosis during feeding.

Although brainstem immaturity has been postulated as one of the pathogenesis underlying cyanosis during feeding (CDF), there has been no widely accepted physiologic parameter that reflects brainstem function. We recently proposed that the dissociation index (DI), one of the phasic sleep parameters, is a reliable and quantitative sleep parameter for assessing brainstem maturation during early infancy. In the present study, we evaluated brainstem impairment in infants with CDF using phasic sleep components. Polysomnographies were obtained for 12 infants with CDF who were equally divided into 2 groups: one had or subsequently experienced apparent life-threatening events or sudden infant death syndrome (ALTE-SIDS group) and the other did not (CDF group). Rapid eye movement density and the number of gross movements (body movements, including the trunk, lasting greater than or equal to 2 sec) in the patients were identical to those in the controls. In the CDF group, the decrease of the average DI value from the controls was significantly less than the decrease in the ALTE-SIDS group. CDF may be a mild expression of brainstem immaturity. DI appears to be useful when evaluating infants with cyanosis during feeding.

Congenital fiber type disproportion myopathy in Lowe syndrome.

Two brothers with the typical clinical features of oculocerebro-renal syndrome of Lowe exhibited delays in developmental milestones, muscular weakness and hypotonia, and high serum creatine kinase activity. The biopsied muscle revealed selective type 1 fiber atrophy and mild type 1 fiber predominance, similar to that observed in congenital fiber type disproportion myopathy. The abnormal fiber type distribution may be responsible for the common finding of muscle hypotonia in this syndrome.

Impairment of respiratory rhythmogenesis and sequelae of bacterial meningitis.

A 9-year-old boy with respiratory disturbance associated with medullary lesions after pneumococcal meningitis is reported. Although he lives a normal daily life, he cannot cough or sneeze. A polysomnographic study revealed a low respiration rate and an irregular respiratory rhythm not only during REM sleep but also during slow wave sleep, and marked desaturation during sleep. Respiratory function tests including CO2 response revealed normal values. Magnetic resonance imaging demonstrated bilateral small lesions in the medulla. This patient is unusual because respiratory rhythm is impaired, without decreased ventilatory capacity or CO2 response, supporting the possibility that rhythmogenetic respiratory neurons are located in a limited area of the human medulla.

[Body movements during sleep in Lennox syndrome].

In Lennox syndrome the brainstem which plays important roles in regulating sleep and its parameters is thought to be disturbed. In order to clarify the importance of the dysfunction of the brainstem in Lennox syndrome, polygraphic examination were studied and their findings were assessed with prognosis. 8 patients aged from 6 to 17 years were subjected to this study. They were divided into two groups according to their prognosis. Group 1 showed good prognosis. Seizures were easily controllable and have not occurred for more than 24 months. In group 2 seizures were intractable and were uncontrollable by medication. In 4 normal children ranging in age from 4 to 10 years, the same studies were performed. Recordings were performed on two consecutive nights and the second night recordings were used for analysis. Polygraph consisted of EEG from C4 and P4, bipolar EOG from electrode attached to outer canthus, surface EMG from submental muscle and 5 or 6 other muscles including trunk and limbs. Sleep stages were determined in each minute according to the standard of APSS. Body movements were classified into two types on the basis of their distribution over body parts and on duration of movements. Gross movements (GM) involved the body trunk and lasted for more than two seconds. Twitch movements (TM) were localized in one muscle on surface EMG recordings lasting less than 0.5 seconds. In normal children, the rate of GM in sleep stage 1 and REM are significantly higher than slow wave sleep. And this is the same in TM of all muscles.(ABSTRACT TRUNCATED AT 250 WORDS)