Amplitude-integrated EEG colored according to spectral edge frequency.

OBJECTIVE: To improve the interpretability of figures containing an amplitude-integrated electroencephalogram (aEEG), we devised a color scale that allows us to incorporate spectral edge frequency (SEF) information into aEEG figures. Preliminary clinical assessment of this novel technique, which we call aEEG/SEF, was performed using neonatal and early infantile seizure data. METHODS: We created aEEG, color density spectral array (DSA), and aEEG/SEF figures for focal seizures recorded in seven infants. Each seizure was paired with an interictal period from the same patient. After receiving instructions on how to interpret the figures, eight test reviewers examined each of the 72 figures displaying compressed data in aEEG, DSA, or aEEG/SEF form (12 seizures and 12 corresponding interictal periods) and attempted to identify each as a seizure or otherwise. They were not provided with any information regarding the original record. RESULTS: The median number of correctly identified seizures, out of a total of 12, was 7 (58.3%) for aEEG figures, 8 (66.7%) for DSA figures and 10 (83.3%) for aEEG/SEF figures; the differences among these are statistically significant (p=0.011). All reviewers concluded that aEEG/SEF figures were the easiest to interpret. CONCLUSION: The aEEG/SEF data presentation technique is a valid option in aEEG recordings of seizures.

[Paroxysmal automatic movements mimicking neonatal seizures induced by midazolam].

We have observed paroxysmal automatic movements including drum-beating and pedaling motions in three full-term neonates following intravenous bolus injections (0.1-0.3 mg/kg/dose) or drip infusions (0.2 mg/kg/h) of midazolam used for sedation. In one patient, abnormal movements were also induced by a bolus injection of midazolam during the EEG recording, and no change was revealed in the EEG during the episode. In another patient, abnormal movements were further worsened by an injection of diazepam. Interictal EEGs of all patients were normal. The clinical manifestations of these paroxysmal automatic movements and the mode of their appearance were quite similar in all patients. It is quite likely that abnormal movements in the patient without ictal EEG change do not have epileptic origin but brainstem release phenomenon induced by midazolam. Because the abnormal movements in the other two cases had similar clinical manifestations and mode of appearance, we suspected that these movements were also non-epileptic though ictal EEGs were not recorded in theses cases. When we encounter paroxysmal automatic movements mimicking neonatal seizures following intravenous midazolam administration, ictal EEG recordings are recommended. If there are no ictal changes, we should avoid treatment with anticonvulsant drugs for these movements. Since midazolam is frequently used in neonates for sedation during various examinations, future investigations on the selection of appropriate drugs and dosage for sedation in neonates, including the usage of midazolam, are necessary.

A CACNB4 mutation shows that altered Ca(v)2.1 function may be a genetic modifier of severe myoclonic epilepsy in infancy.

Mutations of SCN1A, encoding the voltage-gated sodium channel alpha1 subunit, represent the most frequent genetic cause of severe myoclonic epilepsy in infancy (SMEI). The purpose of this study was to determine if mutations in other seizure susceptibility genes are also present and could modify the disease severity. All coding exons of SCN1B, GABRG2, and CACNB4 genes were screened for mutations in 38 SCN1A-mutation-positive SMEI probands. We identified one proband who was heterozygous for a de novo SCN1A nonsense mutation (R568X) and another missense mutation (R468Q) of the CACNB4 gene. The latter mutation was inherited from his father who had a history of febrile seizures. An electrophysiological analysis of heterologous expression system exhibited that R468Q-CACNB4 showed greater Ba(2+) current density compared with the wild-type CACNB4. The greater Ca(v)2.1 currents caused by the R468Q-CACNB4 mutation may increase the neurotransmitter release in the excitatory neurons under the condition of insufficient inhibitory neurons caused primarily by the SCN1A mutation.

Pilot study of universal newborn hearing screening in Japan: district-based screening program in Okayama.

OBJECTIVES: Newborn hearing screening was started in Okayama Prefecture in 2001 as part of a nationwide pilot study in Japan. Nearly 50,000 infants have been screened to date, and an observational study and more than 2 years of follow-up of this population are described in this report. METHODS: Between June 2001 and March 2005 (45 months), 47,346 neonates were screened with automated auditory brain stem response systems and followed up for at least 2 years. This total corresponds to 95% of the infants born in the 44 gynecologic institutions in this district. RESULTS: After undergoing the screening process twice, 248 infants (0.52%) received referrals; 108 of them had apparent bilaterally affected hearing, and 140 had apparent unilaterally affected hearing. Among the bilateral cases, hearing impairment was diagnosed in 40 infants, for a total prevalence of hearing impairment of 0.08%. In 3 additional infants who received a bilateral pass result and 1 infant who received a unilateral pass result, hearing impairment that was progressive or of late onset was subsequently diagnosed. The positive and negative predictive values were calculated as 40% and 99.993%, respectively. CONCLUSIONS: The screening program was carefully designed to work in the Japanese society and to be well managed in Okayama Prefecture.

A screening test for the prediction of Dravet syndrome before one year of age.

PURPOSE: Our aim was to develop a screening test to predict Dravet syndrome before the first birthday based on the clinical characteristics of infants and the SCN1A mutation analysis. METHODS: Ninety-six patients who experienced febrile seizures before the age of one were enrolled. The patients were divided into two groups-the Dravet syndrome group (n = 46) and the non-Dravet syndrome group (n = 50). We compared the clinical characteristics before one year of age of the two groups. We analyzed all coding exons of the SCN1A gene by the direct sequencing method. Scores from 0 to 3 were assigned to each risk factor based on the odds ratio and p-value. RESULTS: An age of onset of febrile seizure or= 5, and prolonged seizures lasting more than 10 min. were regarded as significant risk factors for Dravet syndrome. Other factors highly predictive of this syndrome were hemiconvulsions, partial seizures, myoclonic seizures, and hot water-induced seizures. A total clinical score of six or above was the cutoff value indicating a high risk of Dravet syndrome. SCN1A missense and truncated mutations were detected significantly more often in the Dravet syndrome group than in the non-Dravet syndrome group. DISCUSSION: This simple screening test was designed to be used by general pediatricians. It could help to predict Dravet syndrome before one year of age. If the sum of the clinical risk score is >or= 6, then the performance of an SCN1A mutation analysis is recommended.