新生児聴覚スクリーニング後の精密検査のために当科を受診した児について, 聴覚発達チェックリスト (田中・進藤式) の経過を検討した。両側正常群の経過から到達月齢の成長曲線を作成した結果, 到達月齢の平均-2SDは実際の月齢-1ヶ月となり, 従来の判定基準と同様であった。一側難聴群の到達月齢は, 成長曲線の平均±1SDに入っていた。軽度難聴群では, ばらつきが多くなったが平均±2SDに入っていた。高重度難聴の到達月齢は, いずれも成長曲線から外れていた。中等度難聴については, 聴力60dBの1例は, 生後3ヶ月までは正常群と同様の経過であったが, その後成長曲線から外れた。一方, 聴力50dBの1例は, 精神運動発達遅滞を重複しているにも関わらず, 生後9ヶ月まで平均-2SDの範囲に入っており, 聴覚発達チェックリストで抽出できる聴力レベルの限界が示唆された。

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It is essential to use an infrared CCD camera in clinical examination of the vestibular system. Devices are currently available that can quite accurately record human eye movements, based on the principle of video-oculography (VOG). We devised an original video-oculography (HI-VOG) system using a commercialized infrared CCD camera, a personal computer and public domain software program (ImageJ) for the data analysis. The video image from the infrared CCD camera was captured at 30 frames per second at a resolution of 640*480 pl.. For analysis of the horizontal and vertical components, the X-Y center of the pupil was calculated using the original macro. For analysis of torsional components, the whole iris pattern, which was rotated by 0.1 degree, was overlaid with the same area of the next iris pattern, and the angle at which both iris patterns showed the greatest match was calculated. For quantitative analysis, the slow phase velocity of each occurrence of nystagmus, the average value of the slow phase velocity and the visual suppression value, were analyzed automatically. Analyses of the eye tracking test, as well as the test for optokinetic nystagmus were also applied in this system. Using the HI-VOG system, it was possible to inexpensively perform nystagmus analysis from video images recorded with an infrared CCD camera.

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In this study we used the trapezoid rotation test to evaluate vestibular function in normal guinea pigs or guinea pigs with peripheral vestibular disorder. Post-rotatory nystagmus (PRN) was recorded on videotape under dark conditions with an infrared charge-coupled device camera. The analysis was performed using the pubic domain NIH Image program, and the horizontal and vertical components were calculated automatically. The mean value of maximum slow phase velocity (MSPV) in the normal guinea pigs and guinea pigs with vestibular disorder was 37.288±9.423 degree/sec and 9.786±2.758 degree/sec respectively. There was a significant correlation between the PRN number and MSPV.
We consider that this system makes it possible to evaluate vestibular function in animal models easily and inexpensively.

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　近年, 画像認識技術やハードウェアの進歩に伴い, 赤外線 CCD/CMOS カメラによって得られた眼球運動の画像をコンピュータで画像解析をするビデオ眼振検査 (videooculography: VOG) が普及してきた. VOG における画像解析の原理は, 眼球運動の水平・垂直成分は画像を二値化して瞳孔を抽出し, 瞳孔中心座標から求め, 回旋成分は虹彩の輝度のコントラストプロファイルから求める方法が主流である. われわれは, 眼球認識の自動化や処理速度の向上などプログラムを進化させ, 検査中のリアルタイム三次元眼振図表示を可能にした製品を開発した. 医療機器として研究用途のみではなく, 臨床用途にも使用しやすくなった.

　リアルタイム VOG では, 検者自身が眼球運動動画と眼振図の両者を確認しながら検査を行うことができるため, 検査中に手応えを持って所見を把握することができる. 眼振の回旋成分について, 慣れないと方向を判定しにくいことがあるが, 眼振波形を確認することで回旋の方向を正確に把握しやすい. 数秒前にどんな眼振だったか, 動画の観察のみではあいまいになることがあるが, 眼振図により眼振の強さの変化や方向の変化などを確認することができる.

　そのほか, コンピュータ解析の特性を生かし, 定量的評価として眼振緩徐相速度の計測や, 頻度, 振幅を計測し, 眼振の特徴を数値化することができる. 検査中には判断が困難な場合でも, あとで見直す際, 動画と眼振図の両者を確認して評価することができる. 赤外線フレンツェルに加速度センサー・角速度センサーを備えることにより, 頭位を感知し眼球動画と同期して記録することができる. 出現した眼振の頭位や潜時を正確に確認することができる.

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The purpose of the present study was to verify our hypothesis that perception of the outer world determines sensations, eye movements and bodily movements. We did so by assessing the effects of Coriolis stimulation under a μG condition during parabolic flight. Using a suspended rotary chair, we subjected five young men to Coriolis forces under μG and 1-G conditions. Wearing a linear accelerometer on their chest, and goggles with a CCDcamera, which recorded eye movements, each subject was rotated clockwise at speeds of 50, 100, 150 deg/s under 1 G and at 100 deg/s under μG. Under the 1-G condition, the subject's body was displaced in response to inertial inputs provoked by Coriolis stimulation, i.e., momentarily accelerated leftwards while bending during clockwise rotations. Torsional nystagmus, moving sensation, and motion sickness were produced under 1 G. Under the μG condition, subjects shifted slightly to the right, but nystagmus was as pronounced as that under 1 G. Moving sensation and motion sickness were far less pronounced under μG than under 1 G. The results can be explained by our hypothesis. When gravity provides the Z-axis of the three-dimensional outer world, inertial inputs from the labyrinths displace the coordi-nates in the head, producing body sways, nystagmus and moving sensations. Because the Z-axis of the outer world is not ordained under μG, inertial inputs do not influence spatial orientation. Thus, neither body movements nor moving sensations are produced. However, because gaze is controlled by both head and eye movements, eye movements in the head are evoked directly by head movements, whether or not orientation in space is based on gravity. Space motion sickness is likely provoked by a failure in posture control depending on the outer world under 1 G.

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Recently, the method for diagnosis of benign proximal positional vertigo (BPPV) improved by the spread of infrared charge-coupled device (CCD) cameras. However, central positional vertigo may be involved in cases of positional vertigo and it is necessary to perform the diagnosis carefully.
Since we experienced a case of brainstem malignant lymphoma with rotatory nystagmus in the positioning nystagmus test on the first medical examination, we reported the case. Although the chief complains were a floating sensation, nausea, and vomiting, along with medical treatment progress, the condition has improved gradually and rotatory nystagmus has also disappeared.

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Interest in combining the studies of molecular biology and behavior is motivating research into the eye movements of guinea pigs. Unfortunately, recording eye movements in this small animal is technically difficult. We therefore investigated the measurement of spontaneous eye movements, (vestibulo-ocular reflexes, VOR) in alert guinea pigs using a method for obtaining calibrated eye movement images.
During sinusoidal rotation (0.1-0.3 Hz, peak angular velocity: 60 deg/sec), VOR was recorded on videotapes under dark conditions using an infrared charge-coupled device (CCD) camera. The analysis was performed using public domain NIH Image program (developed by the U.S. National Institute of Health), and the horizontal and vertical components were calculated automatically. The VOR gain ranged from 0.343±0.052 (mean±SD) at 0.1 Hz to 0.321±0.056 at 0.3 Hz (n=20).
This technique allows VOR gains to be measured in conscious guinea pigs.

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　Several tools are available for the evaluation of nystagmus or eye movements, such as Frenzel glass, electronystagmography (ENG), and infrared video goggles. Although ENG is used as a quantitative examination for recording eye movements, it does not permit the recording of the torsional component of nystagmus. Videooculography (VOG) provides evaluation of all the three-dimensions of eye movements, including of the horizontal, vertical and torsional components. In addition, recent technological developments have improved VOG as a research and clinical tool. Progress has been made in the investigational capability of VOG, including the possibilities of performing quantitative evaluation of nystagmus, the visual stimulation test, filing system linkage, high-speed recording, and the video head impulse test (vHIT).

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　In order to comply with the amended act on the protection of personal information, a new technique to blur the iris pattern was developed using the public domain software, ImageJ. Gaussian blur was performed automatically on the iris pattern. Using this program, video movies were created with the iris blurred in five stages and we examined whether it was possible to analyze the torsional direction of nystagmus. The analysis revealed that when the σ of Gaussian blur was 4 or more, the accuracy of the analysis could no longer be maintained. Using this technique, it was possible to delete the information of the iris pattern for protection of personal information.

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Intracranial hypotension, caused by lumbar puncture, spinal anesthesia, arachnoidal cyst, and arterio venous malformation, has become increasing common. Symptoms vary including vertigo, tinnitus, hearing loss, headache, photophobia, and nausea. These are relieved upon reclining and are worsened by sitting or standings. We treated a patient in whom dizziness and tinnitus were evoked after anesthesia, and downbeating vertical nystagmus, was recorded by infra-red CCD camera. Our findings suggested this patients nystagmus was caused by downward displacement of the cerebellum due to intracranial hypotension.

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