[Study on normal reference range of smooth tracking gain for healthy young people]

Objective:Analysis of normal reference value of smooth pursuit test for normal young people. Method:Thirty normal young volunteers were tested by Synapsys videonystagmography. The maximum horizontal tracking angle was 30 °, the vertical maximum tracking angle was 20°, and the frequency was 0.30 Hz, 0.45 Hz and 0.60 Hz, respectively， and the gain under different conditions is used as the observation index. Result:When the frequency is 0.3 Hz, 0.45 Hz, 0.60 Hz, the left and right horizontal gain is 0.92±0.07/0.93±0.07, 0.87±0.08/0.88±0.11, 0.79±0.11/0.78±0.13, respectively, and the asymmetry of left/right gain is 0.021±0.017, 0.031±0.026, 0.037±0.040; the up and down vertical gain is 0.82±0.16/0.80±0.16, 0.78±0.17/0.72±0.15, 0.68±0.20/0.61±0.15, and the asymmetry of the upper/lower gain is 0.046±0.045, 0.069±0.058, 0.109±0.076. Comparing and analyzing the paired left and right gain values of the three frequencies by paired t test, the differences were not statistically significant （P>0.05）. Paired t -test of gain value for different frequency of up and down stationary tracking, the difference was not statistically significant at 0.30 Hz（P>0.05）, but the gain at 0.45 Hz and 0.60 Hz has significant difference（P<0.05）. Comparing the gains of different frequencies in the same direction, the differences in analysis of variance were statistically significant（P<0.05）. Conclusion:The gain value of smooth pursuit test for normal young people can be affected by tracking frequency and direction. At the same frequency, the left/right tracking of 3 frequencies and the up/down tracking gain values of 0.30 Hz are symmetrical, but at 0.45 Hz and 0.6 Hz, the up tracking gain is greater than the down tracking gain, and the gain value in the same direction gradually decreases with the increase of frequency, is the clinical smooth pursuit test is mainly based on 0.30 Hz.