Nippon Jibiinkoka Gakkai Kaiho
Online ISSN : 1883-0854
Print ISSN : 0030-6622
ISSN-L : 0030-6622
Volume 82, Issue 12zokan
Displaying 1-1 of 1 articles from this issue
  • YUKIO WATANABE
    1979 Volume 82 Issue 12zokan Pages 1553-1575
    Published: December 20, 1979
    Released on J-STAGE: March 19, 2008
    JOURNAL FREE ACCESS
    In order to facilitate to make an objective diagnosis and to take more detailed informations about nystagmus responses, the author has developed a computer program for analyzing the ENG recordings of routine equilibrium examinations. The program was designed so that the results of computer analysis could approximate to the results of manual evaluation.
    The output signal of an ENG was sent through an analog to digital converter into a PDP-11/40 computer and eye movements were stored to magnetic disc together with the recording of the ENG.
    The algorithm to analyse nystagmus waves was as follows.
    1. The maximum value of the fast phase was identified.
    2. The points which marked the start and the end of each beat of nystagmus were identified based on the detected fast phase.
    3. An ENG recording was a combination cf nystagmus plus artifacts, such as, rectangular waves and other irregular waves caused by eye movements other than nystagmus, eye blinking, EMG and so on, which should be eliminated in the analysis of nystagmus. In the third step, the author selected the typical waves of nystagmus only by the methods of linear discriminant fuction.
    4. The program computed parameters to evaluaee each clinical examinations such as, spontaneous nystagmus, positional nystagmus, caloric nystagmus and optokinetic nystagmus. The computed parameters were total number of nystagmus, the maximum slow phase velocity, average frequency of nystagmus, total amplitude, CP % and DP % of caloric nystagmus difference between right and left directed nystagmus in optokinetic nystagmus and so on.
    In the clinical use, these analysis were immediatly performed after the completion of ENG examinations and the results of analysis were printed on a terminal installed in examination room as on-line analysis. In the author's clinical applications, the results of computer analysis approximated to the results of manual analysis as expected in the program planning.
    For the research purpose, the recorded eye movements and the results of analysis described so far have been available to compute more detailed and experimental parameters as off-line analysis. In the present studies, the following analysis has been performed, such as, the correlation between amplitudes and velocities, the difference between optokinetic stimulation and induced nystagmus and so on. By these analysis, some pathological findings have been pointed out in the cases of central nerve disorders in which the conventional parameters (number of nystagmus, maximum velocity) indicate nomal value.
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