Increased right auditory cortex activity in absolute pitch possessors.

We recorded the auditory-evoked magnetic fields from children and adults with absolute pitch during the following tasks: (1) hearing 1000 Hz pure tones inattentively, (2) hearing eight random tones inattentively and (3) listening to eight random tones and identifying each tone. In children with absolute pitch, there was no significant positive correlation between the appearance rate of N100m and the kinds of tasks. In adults with absolute pitch, only the right N100m dipole moments increased significantly in tasks (1) and (2). The present results suggest that the circuit for labeling in the right auditory cortex may lose a function from childhood to adulthood, which reveals neuroplasticity in the development of absolute pitch ability.

A magnetoencephalographic study of negative myoclonus in a patient with atypical benign partial epilepsy.

PURPOSE: To clarify the neurophysiological mechanism of epileptic negative myoclonus (NM) of a patient with atypical benign partial epilepsy whose NM was completely suppressed with ethosuximide. METHODS: Polygraphic recordings of whole-head type magnetoencephalography (MEG), EEG and electromyography were made during NM of the bilateral hands. The silent period of 200-400 ms duration in the bilateral biceps muscles was associated with paroxysmal spikes on EEG and MEG. Single equivalent current dipoles (ECD) were calculated for each spike component associated with NM and the estimated generator sources of spikes were superimposed on the patient's head MRI. RESULTS: The magnetic fields of each peak associated with NM showed clear single dipole pattern and ECDs of each peak were located in the neck and orofacial division of the primary motor cortex. CONCLUSIONS: Abnormal firing of the neck and orofacial division of the primary motor cortex was associated with NM generation. Taking the beneficial effect of ethosuximide (a T-type Ca2+ channel blocker in thalamic neurons and the corresponding cortex) and the MEG result together, it is suggested that abnormal interaction of the thalamo-cortical network might be closely related to the pathogenesis of NM.

Magnetoencephalographic analysis of rolandic discharges in a patient with rolandic epilepsy associated with oromotor deficits.

The purpose of this study was to clarify the neurophysiologic basis of oromotor deficits in a patient with atypical rolandic epilepsy. We investigated magnetoencephalographic analysis of rolandic discharges with right predominance before and during clonazepam therapy. Before clonazepam administration, current sources of rolandic discharges were broadly distributed in the secondary sensory cortex, superior temporal gyrus, and parietal association area in addition to hand and orofacial division of the primary somatosensory cortex. During clonazepam therapy, oromotor deficits were improved, along with a decrease in rolandic discharge, and current sources of residual right-sided rolandic discharges were shifted to the right superior parietal lobule. Taking the clinical course and magnetoencephalographic findings together, the distributed rolandic discharge focus might be closely related to oromotor deficits, and clonazepam was effective for the disorder.

N100m in adults possessing absolute pitch.

We recorded the auditory evoked magnetic fields from adults with and without absolute pitch under the following conditions: hearing 1000 Hz pure tones inattentively (single tone session) and listening to eight random tones and identifying each tone (labeling session). In the adults with absolute pitch, the bilateral N100m dipole moments increased significantly in the labeling session. While, in the adults without absolute pitch, the left N100m dipole moment alone increased in the labeling session. These results suggest that the adults with absolute pitch execute the labeling task in the bilateral auditory cortices with interhemispheric cooperation, which does not operate in the adults without absolute pitch.

Children are sensitive to averted eyes at the earliest stage of gaze processing.

Event-related responses to a face with forward gaze or averted gaze (gaze task) and two equiluminous mosaic images (mosaic task) were recorded from healthy children aged 8-12 years and adults, using MEG and EEG. In children, a clear occipito-temporal magnetic field activity (P1m, around 140 ms) was observed bilaterally, and the right P1m amplitude was increased when viewing a face with averted gaze compared with that when viewing a face with forward gaze. This effect was not observed in adults. Furthermore, the source for the right P1m in children in the gaze task was mainly located around the putative human MT/V5 area. These data suggest that the early occipito-temporal brain response observed as the P1m is a gaze-sensitive component in children.

Patients with benign rolandic epilepsy have a longer duration of somatosensory evoked high-frequency oscillations.

BACKGROUND: High-frequency oscillations (HFO) ranging between 300-900 Hz have been shown to be superimposed on an early component of somatosensory evoked potentials (SEP) to median nerve stimulation in humans. Although the HFO are speculated to be a localized activity of the GABAergic inhibitory interneurons, the significance in the epileptogenicity remains unclear. The authors of this study analyzed HFO using magnetoencephalography in patients with benign rolandic epilepsy (BRE) to clarify the neurophysio-logical basis of rolandic discharges (RD). METHODS: Nine patients with BRE and six patients with other epileptic syndrome (non-BRE) participated in the study. Somatosensory evoked fields (SEF) including HFO to median nerve stimulation were measured in a magnetically shielded room with a 37-channel neuromagnetometer. RESULTS: Two kinds of HFO, 300 Hz- and 600 Hz-HFO, were identified and the duration of the HFO in patients with BRE was significantly longer than that in patients with non-BRE. CONCLUSIONS: The results suggest that the longer part of HFO (P30m-related) is closely related to the pathogenesis of RD and that the longer HFO in patients with BRE might be mediated by altered GABAergic inhibition modulated by the cholinergic system.

N100m in children possessing absolute pitch.

We recorded the auditory evoked magnetic fields from children with and without absolute pitch under the following conditions: (a) hearing 1000 Hz pure tones inattentively, (b) hearing eight random tones inattentively and (c) listening to eight random tones and identifying each tone. We calculated the appearance rate of N100m as the ratio of the subjects who had N100m. There was a significant positive correlation between the appearance rate of N100m and age in both groups. There was also a significant positive correlation between the appearance rate of N100m and the kinds of the task only in children without absolute pitch. These results suggest that, in the children with absolute pitch, N100m was elicited equally in every session because of their automatically driven auditory attention. No significant correlation was found between the appearance rate of N100m and the possession of absolute pitch.

A family of episodic ataxia type 2: no evidence of genetic linkage to the CACNA1A gene.

Episodic ataxia type 2 (EA2) has been reported to result from mutations in the CACNA1A gene, located on chromosome 19p13. We describe a family with episodic ataxia, clinically indistinguishable from EA2, that was not caused by CACNA1A gene mutation. The proband is an 11-year-old boy, who has had 6 cerebellar ataxic attacks since 8 years of age. His attacks occurred almost monthly, lasting for 2 to 3 days. He was treated successfully with acetazolamide. His identical twin, mother and grandmother developed ataxic attacks at age 10, 34, and 50, respectively. The symptoms in his grandmother improved gradually without medication. His mother and identical twin took acetazolamide with a good response. We examined the CACNA1A gene for this family but did not detect any mutations. Furthermore, there was no evidence of genetic linkage between the CACNA1A gene and the symptomatic patients in this family. This suggests that the cause of EA2 can be heterogeneous, that is, defects of genes other than CACNA1A might be the cause of EA2.

A case of left ventricular endomyocardial fibrosis.

The patient was a 29-year-old woman. When she consulted a local physician with chief complaints of fever and fatigue of the extremities, cerebral infarction was detected on MRI, in addition to abnormalities found on ECG. Ultrasonic cardiography revealed the presence of a tumor in the left ventricle. Therefore, tumorectomy and endocardectomy were performed under extracorporeal circulation based on a diagnosis of cardiac tumor. Inflammatory cell infiltration into the ventricular wall was pathologically confirmed, and eosinophilia was observed preoperatively. Therefore, the patient was diagnosed as having endomyocardial fibrosis, which is rarely observed in Japan. The postoperative course of this patient was satisfactory, and the eosinophil count was normalized postoperatively. At present, this patient is being followed at the outpatient clinic.

People with absolute pitch process tones with producing P300.

We recorded a P300 component of event-related potentials associated with auditory oddball tasks in nine absolute pitch (AP) possessors and seven non-AP possessors. The previous studies demonstrated that AP possessors did not appear to employ working memory during auditory oddball tasks because they have a fixed tonal template in their memories. However, the present findings showed that the AP possessors exhibited similar P300 as the non-AP possessors and did update the tonal context in the auditory oddball tasks. This result suggests that the AP possessors do not always refer to the fixed tonal template in their memories when executing the oddball tasks and they employ working memory properly according to the difficulty of the auditory tasks.

Analysis of the AAAS gene in a Japanese patient with triple A syndrome.

Triple A syndrome, also known as Allgrove syndrome, is a rare autosomal recessive disorder characterized by adrenal insufficiency, achalasia and alacrima. It has recently been reported that this syndrome is caused by mutations in the AAAS gene. In the present study, we analyzed the AAAS gene in a Japanese patient with triple A syndrome. The patient was a Japanese girl previously reported by Hirose et al. (J Jpn Pediatr Soc 102: 912-915, 1998). The parents of the patient were first cousins. The patient was confirmed to have alacrima and isolated glucocorticoid deficiency at the age of 2 years. She later developed achalasia of the cardia, and was diagnosed as having triple A syndrome. The AAAS gene was amplified by the PCR method, and the PCR products were directly sequenced. The patient was homozygous for a novel nonsense mutation Q237X, changing codon 237 encoding Gln (CAA) to a stop codon (TAA). The parents were heterozygous for the Q237X mutation. The AAAS gene encodes a protein of 546 amino acids, ALADIN. The Q237X mutation is predicted to result in a truncated and presumably non-functioning ALADIN protein, thus causing the clinically manifest syndrome in the patient. To our knowledge, this is the first report on AAAS gene mutations in Japan.

[An infection with Legionella pneumophila treated with intravenous ciprofloxacin].

A 60-year-old diabetic man who had had a coronary artery bypass graft operation was admitted to Okaya Enrei Hospital because of coughing, high fever and dyspnea. Chest high-resolution computed tomography scans revealed bilateral pleural effusions and left-sided alveolar shadows and ground glass opacity. These infiltrations in the left lung field showed rapid growth. Legionella pneumonia was diagnosed because of a high titer for Legionella pneumophila antigen in the urine. He was treated with 600 mg per day of parenteral ciprofloxacin for two weeks and 10 mg per day of oral prednisolone for the second week, resulting in improvement of the clinical findings.