Eye movement control in reading unspaced text: the case of the Japanese script.

The present study examines the landing-site distributions of the eyes during natural reading of Japanese script: a script that mixes three different writing systems (Kanji, Hiragana, and Katakana) and that misses regular spacing between words. The results show a clear preference of the eyes to land at the beginning rather than the center of the word. In addition, it was found that the eyes land on Kanji characters more frequently than on Hiragana or Katakana characters. Further analysis for two- and three-character words indicated that the eye's landing-site distribution differs depending on type of the characters in the word: the eyes prefer to land at the word beginning only when the initial character of the word is a Kanji character. For pure Hiragana words, the proportion of initial fixations did not differ between character positions. Thus, as already indicated by Kambe (National Institute of Japanese Language Report 85 (1986) 29), the visual distinctiveness of the three Japanese scripts plays a role in guiding eye movements in reading Japanese.

Optimal viewing position in vertically and horizontally presented Japanese words.

In the present study, the optimal viewing position (OVP) phenomenon in Japanese Hiragana was investigated, with special reference to a comparison between the vertical and the horizontal meridians in the visual field. In the first experiment, word recognition scores were determined while the eyes were fixating predetermined locations in vertically and horizontally displayed words. Similar to what has been reported for Roman scripts, OVP curves, which were asymmetric with respect to the beginning of words, were observed in both conditions. However, this asymmetry was less pronounced for vertically than for horizontally displayed words. In the second experiment, the visibility of individual characters within strings was examined for the vertical and horizontal meridians. As for Roman characters, letter identification scores were better in the right than in the left visual field. However, identification scores did not differ between the upper and the lower sides of fixation along the vertical meridian. The results showed that the model proposed by Nazir, O'Regan, and Jacobs (1991) cannot entirely account for the OVP phenomenon. A model in which visual and lexical factors are combined is proposed instead.

Re-evaluation of the hypoxia theory as the mechanism of hyperventilation-induced EEG slowing.

To determine whether the well-accepted hypoxia theory accounts for hyperventilation-induced electroencephalogram (EEG) slowing, the authors monitored changes in cerebral oxygenation and end-tidal concentrations of carbon dioxide in 67 patients with epilepsy (age range = 5-12 years) during the hyperventilation activation test in a routine EEG examination. Relative concentration changes in cerebral oxygenated, deoxygenated, total hemoglobin, and oxidized cytochrome oxidase were measured by near-infrared spectroscopy in the frontal region. In all patients, except one who demonstrated EEG slowing, total and oxygenated hemoglobin decreased, and cytochrome oxidase was not reduced. EEG slowing occurred intermittently in 22 patients and was not synchronous with changes in either the cerebral oxygenation or end-tidal concentration of carbon dioxide. The degree of EEG slowing was diminished or the slow waves disappeared abruptly within 1 second after the cessation of hyperventilation in 22 patients when both the cerebral oxygenation and end-tidal concentration of carbon dioxide were still at low levels. The findings during the recovery periods do not confirm the hypoxia theory. It is thus supposed that more subtle mechanisms are the cause of EEG slowing.

Long-term effects of zonisamide in the treatment of epilepsy in children with intellectual disability.

Zonisamide is a new drug with broad-spectrum antiepileptic activity against partial as well as generalized seizures. The purpose of the present study was to compare the long-term efficacy of zonisamide in the treatment of epilepsy in children with intellectual disability (ID) with those with normal intelligence (NI). One hundred and thirty children (74 ID, 56 NI) were included in the study. Fifteen of the subjects were eliminated from the study because of adverse effects or aggravation of seizures. The remaining 115 children (66 ID, 49 NI) were followed up for more than one year. Twenty-eight children (6 ID, 22 NI) were in zonisamide monotherapy. The mean numbers of different antiepileptic drugs were 4.5 and 3 for the ID and NI groups, respectively. The overall improvement rates, defined as a >50% reduction in the number of seizures, were 41% (ID) and 67% (NI) (P<0.01). Side-effects were observed in 27% and 30% of subjects in the ID and NI groups, respectively. However, in the monotherapy group, side-effects were observed in 50% (ID) and in 27% (NI). In conclusion, the effectiveness of zonisamide was weaker in children with ID than those with NI. This is in agreement with the known phenomenon that epileptic children with ID are likely have more intractable seizures than those with NI.

Abducent nerve paralysis during interferon alpha-2a therapy in a case of chronic active hepatitis C.

A 59-year-old woman with chronic active hepatitis C was treated with recombinant human interferon alpha-2a. After three days of administration, the patient complained of diplopia with dizziness and head heaviness. Ophthalmic examinations revealed a disturbance of the movement of left eye ball to the outer side without any other neurological signs. The diplopia, which was diagnosed as abducent nerve paralysis, improved rapidly and reversed at about 6 weeks after discontinuation of interferon and during infusion of hydrocortisone. To our knowledge, this is the first report of abducent nerve paralysis associated with alpha-2a interferon.

Familial occurrence of moyamoya disease. Magnetic resonance angiography as a screening test for high-risk subjects.

The authors report four cases of familial occurrence of moyamoya disease. Although the pathogenesis of moyamoya disease is not clear, there is extensive evidence that this disease has a tendency to show multifactorial inheritance. Therefore, a screening test for those at high risk, i.e., who have a moyamoya patient among their blood relatives, is clinically important. Magnetic resonance angiography (MRA) successfully revealed abnormal findings specific to moyamoya disease in members of the four probands families. MRA is a powerful and noninvasive way of detecting individuals at high risk of developing moyamoya disease.

[A case of nemaline myopathy combined with recurrent rhabdomyolysis].

A four-year-old boy with cerebral palsy showed marked myoglobinemia and developed acute renal failure. Peritoneal dialysis and exchange transfusion resulted in saving the patient. He had a second episode of rhabdomyolysis after one month. Renal failure did not develop due to forced solute-alkaline diuresis therapy. Muscle biopsy revealed nemaline bodies by the Gomori trichome stain. Serum and muscle carnitine showed a marked decrease.

DNA diagnosis of central nervous system infection by Mycoplasma pneumoniae.

A nested polymerase chain reaction method for the detection of Mycoplasma pneumoniae was devised and applied to clinical samples. This system could detect 5 to 50 fg of the DNA from M pneumoniae and did not amplify the DNA from Mycoplasma genitalium. With this method, the sequence of this organism was detected successfully in cerebrospinal fluid samples from four of six patients and in serum samples from three of four patients with clinically and serologically confirmed mycoplasmal central nervous system infection. This strongly suggested the direct invasion of this organism into the central nervous system and the concomitant occurrence of mycoplasmaremia. The nested amplification method is considered to be simple, rapid, and sensitive without the use of radioisotopes, thereby being highly applicable as a useful tool in routine clinical laboratories for the preliminary detection and diagnosis of mycoplasmal infections, particularly in extrapulmonary cases.

Cortical reflex myoclonus associated with mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes (MELAS): a case report.

A 9-year-old female MELAS patient with myoclonus is reported, with emphasis on the results of electrophysiological studies of the myoclonus. At age 5 years she experienced a stroke-like episode, and a diagnosis of MELAS was made at age 6 years on the basis of muscle biopsy findings. At age 9 years spontaneous and segmental myoclonus, predominantly affecting the upper extremities, developed because of complications. Electrophysiological examination, including of somatosensory-evoked potentials (SEPs) and averaged EMG for long loop reflexes, revealed so-called "giant SEP" and enhanced long loop reflexes reflecting cortical hyperexicitability. Jerk-locked averaging yielded no myoclonus related spikes, but myoclonus-contingent 4-5 Hz theta bursts appeared. These findings suggest that some types of MELAS may be associated with cortical types of myoclonus.

A symptomatic female patient with Duchenne muscular dystrophy diagnosed by dystrophin-staining: a case report.

We report a case of symptomatic carrier of Duchenne muscular dystrophy (DMD) in a 14-year-old girl with no prior family history of DMD. She presented with chest pain, enlarged calf muscles, an elevated serum creatine kinase (CK), and decreased left ventricular function. Histological examination of skeletal muscle revealed myopathic changes and immunostaining with anti-dystrophin antiserum demonstrated a mosaic pattern which are compatible with the observations in carriers of DMD. Southern blots using the dystrophin cDNA revealed no evidence of a deletion within the DMD gene in the patient or in her mother. We found this observation interesting for two reasons: 1. Cardiomyopathy is rare in female DMD patients. 2. Immunostaining of a muscle biopsy with anti-dystrophin serum proved to be valuable in the diagnosed for symptomatic carriers of the dystrophin gene mutation.

Identification of a marker chromosome as inv dup(15) by molecular analysis.

The origin of an extra marker chromosome in a patient with mental retardation and intractable epilepsy was ascertained by DNA analysis. Gene dose and restriction fragment length polymorphism (RFLP) studies of D15S9 proved that the patient was tetrasomic for the gene and that the extra chromosome was of maternal origin. On the basis of the molecular findings, further detailed GTG-banded chromosome analysis interpreted the marker chromosome as inv dup(15)(pter----q14::q14----pter). The clinical manifestations of the patient are consistent with those of the patients previously described.

Renal tubular involvement mimicking Bartter syndrome in a patient with Kearns-Sayre syndrome.

A 10-year-old boy had short stature, external ophthalmoplegia, atypical retinal pigmentary degeneration, and sensorineural hearing loss (Kearns-Sayre syndrome). In addition to ragged-red fibers observed on modified Gomori trichrome staining, there were scattered fibers exhibiting no cytochrome c oxidase activity, indicating a focal deficiency. Cytochrome c oxidase and other respiratory chain enzyme activities were normal biochemically. The patient also had renal tubular dysfunction, including isosthenuria, decreased urine-concentrating ability, and excessive excretion of potassium and magnesium. In addition, he had hyperreninemia and hyperaldosteronism but no hypertension. The renal dysfunction was thought to have resulted from a primary defect in the thick ascending limb of the loop of Henle, mimicking Bartter syndrome. In contrast to previously described cases of cytochrome c oxidase deficiency with de Toni-Fanconi Debré syndrome, the patient had less intensive muscle abnormalities. A renal biopsy specimen showed ultrastructural changes in mitochondria that were similar to those seen in biopsy specimens of muscle. A large-scale deletion (8.8 kilobases) in mitochondrial DNA was found in biopsy specimens of muscle and kidney.

[Ataxia telangiectasia and characterization of its immunological disorders].

Ataxia telangiectasia (AT) is a primary immunodeficiency syndrome characterized by cerebellar ataxia, extrapyramidal signs, oculocutaneous telangiectasia, recurrent respiratory infections and development of malignancies. AT is a complex autosomal recessive disorder involving several systems other than lymphoid cells or the central nervous system. Such a diversity of abnormalities includes hypersensitivity of fibroblasts and lymphocytes to ionizing radiation (anomaly of DNA repair), non-random chromosomal rearrangements in lymphocytes, elevated serum level of alpha-fetoprotein, premature aging and endocrine disorders. A DNA processing or repair protein is the suspected common denominator in this pathology. Whatever the putative common underlying mechanism, AT patients have profound alterations of the humoral and cellular immune system whose mechanisms should be discussed in terms similar to those for other immunodeficiency diseases. The usual immunological abnormalities in this disease include decreased levels of CD 3 and CD 4 positive T lymphocytes, impaired delayed hypersensitivity, hypoplasia of thymus, decreased blast transformation in vitro in response to mitogen or antigenic stimulation, and decreased levels of serum IgA, IgE, and IgG 2 subclass. In this paper, the results of our recent studies on the defects of B cells in patients with AT were presented. (1) We found that the geometric means of IgA production in the supernatants of the lymphoblastoid cell lines established by EB virus, from all patients with AT, were significantly lower than those from healthy controls (P less than 0.01). (2) IgG subclasses of the patients' sera were also measured by ELISA, and IgG 4 was defective in four cases among six patients with AT.(ABSTRACT TRUNCATED AT 250 WORDS)

[An analysis of ictal EEGs by a newly developed ambulatory cassette EEG system].

We evaluated the efficiency of a newly developed cassette EEG recording device and our system for detecting and analyzing ictal EEGs in epileptic children. We got 13 ictal records from 16 epileptic children. We could precisely differentiate and diagnose their classifications of seizures by comparative analyses of ictal records and clinical symptoms. We discussed the characteristics of our system, and described actual analysis methods in 3 cases as examples. It was concluded that our system offered valuable information about ictal events in epileptic children.