| Budget Amount *help |
¥3,800,000 (Direct Cost: ¥3,800,000)
Fiscal Year 2005: ¥1,100,000 (Direct Cost: ¥1,100,000)
Fiscal Year 2004: ¥2,700,000 (Direct Cost: ¥2,700,000)
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| Research Abstract |
To investigate the contribution of eye-head coordination for dynamic visual acuity (DVA) during head rotation, I performed following two experiments.
Experiment I : Normal subjects (n=84) were asked to read and answer 3 numerals, presented sequentially at random order. The numerals moved rightward at 90 deg/s on a CRT monitor during voluntary rightward rotation. Thirty trials were carried out and numbers of correct answers (full score ; 3 x 30 = 90) were evaluated as DVA score. Mean and SD of their DVA score was 37.0 and 7.8.
Experiment II : Six normal subjects repeated the same trial as above for two weeks. Three subjects conducted 125 trials a day (HT group) and another three ones did 25 trials a day (LT group). DVA score in HT group increased from 39.7 to 50.3. Similarly, that in LT group increased from 41.3 to 52.3. The changes of voluntary head motion followed by DVA training, however, completely depended on the subject group. Although the peak head velocity in LT group decreased from 62.1 to 30.1 deg/s, that in HT group apparently increased 43.3 to 79.0 deg/s. The strategy of LT group seems to be reasonable because in this head condition leftward eye movements are thought to be evoked by VOR, which disturbs tracking a moving target. How is the strategy of HT group? Data of subject OZ in HT group gave me a big hint. His head rotation could make an early start and was consequently in deceleration stage when a moving target appeared. Therefore, I considered that leftward acceleration evoked rightward eye movements as VOR. I named this idea "reversal VOR hypothesis". According this hypothesis, rightward VOR and rightward pursuit made a high-speed rightward gaze velocity. Indeed, subject OZ showed 80 deg/s rightward gaze velocity, which can not be explained by only pursuit eye movements.
This "reversal VOR hypothesis" holds the possibility of making effective training way for better DVA.
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