시운동성 안진 및 시운동성후안진에 미치는 두위의 영향

Background and Objectives: Optokinetic nystagmus (OKN) is triggered by image slip on the retina. During optokinetic stimulation, activity related to slow phase eye-velocity in the subcortical pathways is stored by “central velocity storage integrator”. When the optokinetic stimuli, the integrator discharges, generating optokinetic after-nystagmus (OKAN) with fast phases beating in the same direction as the previous OKN. Materials and Methods: Horizontal OKN and OKAN were examined in sitting and 90° left and right lateral position in healthy adults. Optokinetic stimuli (100°sec) were given for 45 second using stripe pattern stimulator and then OKAN was recorded for 45 second. Four parameters which were OKN slow component velocity (OKN SCV), initial slow component velocity of OKAN (init SCV), slow cumulative eye position of OKAN (SCEP), and time constant of OKAN (TC) in the sitting position were calculated in 3 positions. Results: 1) The mean and standard deviation of OKN SCV, init SCV, SCEP and TC in sitting position were 34.9±13.8°/sec, 13.9±6.3°/sec, 211.8±96.5°/sec and 17.1 ±7.0 sec. 2) In the lateral recumbent position, OKN SCV, init SCV, and SCEP were decreased to 76%, 67%, and 85.6%, but TC was increased to 136.3% of those in sitting position. 3) There was no significant difference in all parameters between clockwise and couter- clockwise optokinetic stimuli. 4. The gravity has no significant effect on OKN and OKAN. Conclusion: These results suggest that head position affects OKN and OKAN. J Clinical Otolaryngol 2000;11:60–67)