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50 results on '"Yamagishi, Tatsuya"'

6. Changes in functional connectivity among vestibulo-visuo-somatosensory and spatial cognitive cortical areas in persistent postural-perceptual dizziness: resting-state fMRI studies before and after visual stimulation

Author

Yagi, Chihiro, primary, Morita, Yuka, additional, Yamagishi, Tatsuya, additional, Ohshima, Shinsuke, additional, Izumi, Shuji, additional, Takahashi, Kuniyuki, additional, Watanabe, Masaki, additional, Itoh, Kosuke, additional, Suzuki, Yuji, additional, Igarashi, Hironaka, additional, and Horii, Arata, additional

Published
2023
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23. Optimal Diagnostic Criteria and a Staging System for Otogenic Skull Base Osteomyelitis.

Author

Takahashi, Kuniyuki, Morita, Yuka, Ogi, Manabu, Nonomura, Yoriko, Kitazawa, Meiko, Yagi, Chihiro, Yamagishi, Tatsuya, Ohshima, Shinsuke, Izumi, Shuji, and Horii, Arata

Subjects
SKULL base, MAGNETIC resonance imaging, OSTEOMYELITIS, INFECTION control, TEMPORAL bone
Abstract

Objective  Diagnostic criteria for otogenic skull base osteomyelitis (SBO) have been conflicting among researchers. We aimed to propose clinically useful diagnostic criteria and a staging system for otogenic SBO that is associated with infection control and mortality. Design  The present study is designed as a retrospective one. Setting  This study was conducted at the University Hospital. Participants  Thirteen patients with otogenic SBO who met the novel rigorous diagnostic criteria consisted of symptomatic and radiological signs on high-resolution computed tomography (HRCT) and magnetic resonance imaging (MRI). Simple refractory external otitis was not included. A staging system according to disease extent revealed by HRCT and MRI is proposed: lesions limited to the temporal bone (stage 1), extending to less than half (stage 2), exceeding the midline (stage 3), and extending to the whole of the clivus (stage 4). All patients received long-term antibiotic therapy. Patients were divided into infection-uncontrolled or -controlled groups based on symptoms, otoscopic findings, and C-reactive protein level at the last follow-up. The mean follow-up period was 27.7 months. Main Outcome Measures  Possible prognostic factors, such as immunocompromised status and symptoms, including cranial nerve palsy, pretreatment laboratory data, and treatments, were compared between the infection-uncontrolled and -controlled groups. Disease stages were correlated with infection control and mortality. Results  The infection-uncontrolled rate and mortality rate were 38.5 and 23.1%, respectively. There were no significant differences in possible prognostic factors between the infection-uncontrolled and -controlled groups. HRCT-based stages significantly correlated with infection control and mortality. Conclusion  We proposed here the clinically useful diagnostic criteria and staging systems that can predict infection control and prognosis of otogenic SBO. [ABSTRACT FROM AUTHOR]

Published
2022
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31. 331. RELAPSE CASES OF OTITIS MEDIA WITH AAV (OMAAV)

Author

Morita, Yuka, primary, Takahashi, Kuniyuki, additional, Kitazawa, Meiko, additional, Nonomura, Yoriko, additional, Yagi, Chihiro, additional, Yamagishi, Tatsuya, additional, Ohshima, Shinsuke, additional, Izumi, Shuji, additional, and Horii, Arata, additional

Published
2019
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34. A Cognitive Neuropsychological Approach to the Mechanism of Kana-Kanji Dissociation in Oral Reading

Author

Yamagishi, Tatsuya

Subjects
kanji, triangle model, cognitive neuropsychology, kana
Abstract

application/pdf, 論文(Article), This study examines a fluent aphasic subject with word-finding difficulties and kanji dyslexia who showed significant picture cue effects in oral reading of kana but who showed no such effects when he performed oral reading of kanji. The study applies, based on the triangle model of oral reading, a cognitive neuropsychological approach to the mechanism of kana-kanji dissociation in oral reading exhibited by the subject. The approach was made on the hypothesis that kana words are mainly processed through the phonological route at high conversion rates from orthography to phonology, whereas kanji words are primarily processed through the semantic route at low conversion rates. It is also assumed that picture naming is processed through the semantic route. If the subject has damage to phonological representations, the phonology will not be sufficiently activated through the semantic route and, he may suffer from kanji dyslexia and word-finding difficulties as a result. The subject performed well in oral reading of kana because it is assumed that oral reading of kana effectively activated phonological representations through the phonological route. The subject also exhibited significant picture cue effects in oral reading of kana. This is probably because of the summation effects that were produced by the relatively strong activation of phonology through the phonological route, and by the activation of phonology through the semantic route prompted by picture cueing. In case of oral reading of kanji, on the other hand, it is suggested that the phonological activation through the phonological route did not take place nor did the summation effects by picture cueing.

Published
2010

35. Morphemic Perseverative Blends by a Japanese Phonological Dyslexic in Reading Aloud Two-Kanji Compounds

Author

Yamagishi, Tatsuya and Maruta, Tadao

Subjects
Morphemic carryover, Reading aloud, Perseverative blend
Abstract

application/pdf, 論文(Article), SM, a patient with a brain tumor in the left hemisphere, exhibited the aphasic disorder of recurrent perseveration. This article documents the morphemic carryover perseveration that he produced while reading aloud two-kanji compounds, which is a theoretical possibility if a component kanji (morpheme) is a recognition unit in the reading process. He was also diagnosed as a probable phonological dyslexic because his reading of non-words and single characters was bad and in sharp contrast to his word reading, which was almost intact as far as familiar words were concerned. In standard dual-route reading models, it was envisaged he would persevere with words because his visual word recognition presumably relied on whole words. Contrary to this prediction, SM showed a number of perseverative blends in which an earlier-produced morpheme was carried over to be spliced with a current lexical or morphemic base. Thus SM's perseveration provides valuable information about how orthography and phonology interact while a compound word is being successfully read.

Published
2008

43. Power-Loss Breakdown of a 750-V 100-kW 20-kHz Bidirectional Isolated DC–DC Converter Using SiC-MOSFET/SBD Dual Modules.

Author

Akagi, Hirofumi, Yamagishi, Tatsuya, Tan, Nadia Mei Lin, Kinouchi, Shin-ichi, Miyazaki, Yuji, and Koyama, Masato

Subjects
*CONVERTERS (Electronics), *ELECTRIC power failures, *METAL oxide semiconductor field-effect transistors, *ELECTRIC circuits, *SILICON carbide, *BATTERY storage plants, *WIND power
Abstract

This paper describes the design, construction, and testing of a 750-V 100-kW 20-kHz bidirectional isolated dual-active-bridge dc–dc converter using four 1.2-kV 400-A SiC-MOSFET/SBD dual modules. The maximum conversion efficiency from the dc-input to the dc-output terminals is accurately measured to be as high as 98.7% at 42-kW operation. The overall power loss at the rated-power (100 kW) operation, excluding the gate-drive and control circuit losses, is divided into the conduction and switching losses produced by the SiC modules, the iron and copper losses due to magnetic devices, and the other unknown loss. The power-loss breakdown concludes that the sum of the conduction and switching losses is about 60% of the overall power loss and that the conduction loss is nearly equal to the switching loss at the 100-kW and 20-kHz operation. [ABSTRACT FROM AUTHOR]

Published
2015
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50. Clinical features of persistent postural-perceptual dizziness coexisting with Meniere's disease in comparison with Meniere's disease alone.

Author

Yagi C, Kimura A, Ishida K, Takahashi T, Kai R, Yamagishi T, Oshima S, Izumi S, and Horii A

Abstract

Background: Persistent postural-perceptual dizziness (PPPD) is a chronic vestibular syndrome often triggered by acute or episodic vestibular syndromes, such as Meniere's disease (MD). According to the diagnostic criteria, PPPD may coexist with other structural diseases, and the evidence of another active illness does not necessarily exclude PPPD diagnosis. However, persistent symptoms, even those meeting the PPPD criteria even long after Meniere's attack, are often overlooked as potential PPPD precipitated by MD. Some clinicians overlook PPPD in such patients, treating them solely for MD once diagnosed. Since a treatment strategy for PPPD is completely different from that for MD, this may result in the deprivation of adequate treatments., Objectives: To emphasize the importance of diagnosing PPPD coexisting with MD including not treating such patients solely for MD, and to compare the clinical features of PPPD and MD., Methods: Vestibular function tests, including canal paresis (CP)%, c- and o-vestibular myogenic potentials, vestibulo-ocular reflex-direction preponderance, and posturography and clinical symptom scales, including the Dizziness Handicap Inventory, Niigata PPPD Questionnaire, and Hospital Anxiety and Depression Scale, were compared between 105 PPPD patients with MD or other precipitants and 130 patients with MD alone. The clinical symptom scales were further compared between 23 patients with PPPD coexisting with MD and those with MD alone., Results: The CP% was significantly higher in patients with MD than in those with PPPD. However, the total and subscores of all three clinical symptom scales were higher in patients with PPPD than in those with MD. The total score on all clinical symptom scales was higher in patients with PPPD coexisting with MD than in those with MD alone., Conclusion: Persistent postural-perceptual dizziness development from a precipitating MD may be associated with more severe clinical symptoms. Thus, clinical symptom scales may be useful for detecting PPPD in patients with Meniere's disease., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. The author(s) declared that they were an editorial board member of Frontiers, at the time of submission. This had no impact on the peer review process and the final decision., (Copyright © 2024 Yagi, Kimura, Ishida, Takahashi, Kai, Yamagishi, Oshima, Izumi and Horii.)

Published
2024
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