Kuniaki Fukuda

Short latency somatosensory evoked potential in children

The short latency somatosensory evoked potential was studied in 90 normal children of 1 month to 16 years old and 7 adults. Somatosensory stimuli were delivered through a disc electrode placed over the median nerve at the wrist joint. The uniform recording sites used were the central region of the scalp, and the seventh cervical spine or Erbs point. Reference electrodes were placed on the hand contralateral to the median nerve stimulated. Three positive peaks (P1, P2 and P3) and one negative peak (N1) were consistently recorded, a further positive peak (P4) after N1 was not always observed. The latency of each peak per 1 m body length decreased with age until 2 or 5 years of age. The latency of each peak after 2 years of age was positively correlated with the body length and arm length. The value of P1 peak latency per 1 m body length reaches adult values at an earlier rate than the value of P3 peak latency and P2-P3 latency per 1 m body length. This suggests that central lemmiscal pathways mature at a slower rate than peripheral nerve fibers. The wave form pattern of the short latency somatosensory evoked potential changed to the adult pattern at 10 years of age. The peak latency of P4 during deep sleep was slightly prolonged. In recording on infants during sleep, the EEG should be monitored to determine the stage of sleep.

Postural Effects on Behavioral States of Newborn Infants -A Sleep Polygraphic Study-

Physiological and behavioral correlates of neonates in the supine and prone positions were examined. Polygrams were recorded in 10 newborn infants in the prone and supine positions. Newborn infants slept more in the prone position than in the supine, and quiet sleep was significantly more in the prone position. Gross movement, jerky movement and twitch movement were less in the prone than the supine position. There was no difference in localized movement or tremor-like movement in the two positions. Respiration was more regular in the prone than the supine position. Sleep apnea (greater than or equal to 6 seconds) was less in the prone position. The pulse rate during quiet sleep was higher in the prone position.

Increased body movements during sleep in gilles de la tourette syndrome

Overnight sleep polygrams were recorded form 9 patients with Gilles de la Tourette syndrome (GTS). Six of 9 patients had abnormal electroencephalograms, but no specific abnormalities were detected. Body movements and twitch movements during sleep were analyzed. At all stages of sleep, body movements during sleep were more frequent in cases of GTS than those in normal controls. Twitch movements in stage REM of sleep were significantly increased in GTS. These results are consistent with the idea that GTS is due to an imbalance between the central neurotransmitters, catecholamine and serotonin.

Serial EEG and sleep polygraphic studies on lissencephaly (agyria-pachygyria)

We carried out serial EEG studies on 12 cases of lissencephaly (6 of agyria and 6 of pachygyria), polysomnograms being recorded in 8 of the 12 cases. Fourteen Hz sleep spindles appeared from early infancy in all cases. They were poorly observed after the age of 1 year, and 5-11 Hz high-amplitude rhythmic activity (HARA) of more than 300 microV appeared predominantly in place of the 14 Hz spindles. Both the 14 Hz spindles and HARA showed asymmetry, but the dominant cerebral area for both types of waves was much the same. Four of the 6 agyria cases showed hypsarrhythmia within the first 6 months after birth, 3 of the 4 cases showing asymmetric hypsarrhythmia at first. Their hypsarrhythmia consisted of very high-voltage 5-7 Hz slow sharp waves and delta waves. The EEG abnormalities transformed from hypsarrhythmia to focal spikes in the 6 pachygyria cases. The polygraphic study on 8 cases revealed that the proportion of REM sleep decreased in 3 cases and the REMs/min values decreased in 7. Infantile spasms occurred in 4 of the 8 cases. The REM/min values decreased in all of these 4 cases, and, furthermore, the proportion of REM sleep decreased in 3 of the 4 cases. These findings suggest that lissencephaly involves a disorder of the brainstem, and that the combination of brainstem lesions and severe cerebral dysplasia is important for the manifestation of infantile spasms in lissencephaly.

Influence of acth therapy on overnight sleep polygrams in infantile spasms

Overnight sleep polygrams were recorded before and during therapy in nine patients with infantile spasms. Results showed that ACTH therapy increased the waking time and decreased rapid eye movement sleep. Thus it caused sleep disturbance in patients with infantile spasms. During ACTH therapy the number of rapid eye movements/min and the pulse rate decreased significantly. Body movements/min also decreased, but not significantly. These results suggest that ACTH therapy may inhibit functions of the central nervous system. The respiratory rate increased during ACTH and clonazepam therapy, probably in association with the decrease or the absence of seizures. These findings indicate the necessity for further studies on whether ACTH therapy is really of value in patients with infantile spasms, and show that if ACTH is given, the period of therapy should be as short as possible.

Spinal evoked potentials in normal Japanese infants and children

The spinal evoked potentials on right peroneal nerve stimulation were recorded with surface electrodes in 58 normal children of 41 weeks to 15 years old. Bipolar recordings were performed. In all subjects, tri- or quadri -phasic potentials with poorly defined initial positive phases were recorded. The latency of the evoked potentials increased progressively from the lumbar to cervical location. The peripheral conduction velocity from the stimulating cathode in the popliteal fossa to the lumbar recording location increased until 4 or 5 years, and then reached a plateau. Spinal conduction velocity between the lumbar and cervical locations increased until 7 years, and then remained constant.

A case of lissencephaly (Agyria) syndrome with apnea—Polygraphic study—

A 4-month-old infant with lissencephaly syndrome who was diagnosed on the basis of clinical symptoms and computed tomography experienced four apnea attacks during three polysomnographies. Apnea attacks were of two types. Type I apnea attacks were thought to be sleep apnea. The cause is unknown. Apnea was followed by tonic seizures due to hypoxia. Type II apnea attacks were thought to be epileptic apneic attacks, because they proceeded from the epileptic discharges in the right anterior temporal region (lead of electrooculogram). The origin of Type II apnea attacks was focused in the limbic system.

Sleep Polygraphic Studies on Infantile Spasms

The onset of infantile spasms occurs usually from 4 months to 2 years of age. The infantile spasms is one of the most severe types of epilepsy in childhood. Although there are many theories about the pathophysiological cause of infantile spasms, none have been validated. Gastaut (1 972)l) suggested that the spasms are caused by a brief discharge of the reticular structure. The cause of abnormal discharge is divided into three groups; i.e. hereditary, biochemical and organic disorders. The relationship between sleep and brain stem reticular formation is demonstrated by Jouvets study (1 972)z). Further, the relationship between sleep and epilepsy has been reported in previous literatures (Ross 19669, Kazamatsuri 19644), and Fujimori 19665)). However, the majority of these studies has been done on changes of seizure discharge during each stage of sleep, and there are few works about the disorders of sleep, changes of autonomic nervous function and other parameter during sleep. There are no reports of works about the relationship between sleep and infantile spasms. In this paper, the studies on sleep polygraphy of infantile spasms are described.

Short latency somatosensory evoked potentials to peroneal nerve stimulation in normal Japanese children

Short latency somatosensory evoked potentials (SSEP) were elicited by stimulation of the peroneal nerve in 68 normal children of 39 weeks to 15 years old. In all subjects, three positive potentials (P1, P2 and P3) and one negative potential (N1) were consistently recorded. A further positive potential (P4) after N1 was not always observed. There was no change of wave form with development. P1, P2, P3 and N1 might be generated in subcortical structures; caudal cervical spine, brainstem, thalamus and thalamocortical pathway, respectively. The latency of each peak per one meter body length decreased with age until 5 or 6 years of age. Moreover, the latency between peaks per one meter body length also decreased with age until 5 to 6 years of age. These findings are consistent with the development of SSEP on median nerve stimulation and with the developmental phenomenon of spinal conduction velocity, and might be related to the increase in the diameter and the progressive myelination of nerve fibers.

Biological rhythms in patients with lissencephaly (agyria-pachygyria)

Lissencephaly is a congenital malformation of the brain characterized by an extensive absence of cerebral gyral formation. Polysomnograms were recorded in 8 cases with lissencephaly (4 of agyria and 4 of pachygyria), and 24-h secretion of growth hormone, prolactin, luteinizing hormone, follicle-stimulating hormone and cortisol was examined in 6 of the 8 cases. The sleep-waking cycle and body temperature (BT) rhythm were studied in all 8 cases. The results were as follows: (i) the sleep-waking circadian rhythm was well preserved in 6 of the 8 cases; (ii) %REM (rapid eye movement) sleep decreased in 4 cases, but the ultradian rhythm of REM sleep was well observed in all cases except one; (iii) the secretion of GH and PRL showed normal or borderline increases with sleep; (iv) although these cases had not reached puberty, LH and FSH increased with sleep in 3 of 5 cases; (v) the circadian rhythm of cortisol secretion was preserved in all cases except one; (vi) BT showed a circadian rhythm after infancy. These findings suggest that the circadian rhythms function normally in lissencephaly, that the secretion of GH and PRL during sleep occurs almost normally, and that the cerebral cortex does not play a significant role in the regulation of these biological rhythms in lissencephaly.