Comparative analysis of oculography methods for the diagnosis of the vestibular system
There are various methods of registering eye movement and the most common among them are methods of videooculography (VOG) and electrooculography (EOG). These methods are based on completely different physical principles, and the signals received during eye movements recording, respectively, have different noise sources. Eventually, both methods register the same mechanical movement, and as a result, they should give consistent results. In this regard, the experimental study and analysis of the accuracy of the methods of VOG and EOG while visual saccades registration recorded simultaneously with the use of these methods of oculography were carried out. 12 horizontal saccades to the left with an average peak velocity of Vleft = 150±50 grad/s. nd 10 saccades to the right with an average velocity of Vright = 160±50 grad/s were recorded simultaneously by these two methods. The signals were processed by a low-pass filter with a cut-off frequency of 10 Hz and synchronized in time using cross-correlation. Further, the saccades were averaged separately for each system and the left-right direction. The comparison of visual saccades was carried out using a linear regression model of the dependence of the eye movement velocity, recorded by EOG, on the eye movement velocity, recorded by VOG. A statistically significant different agreement of the recorded eye velocities using EEG and VOG during horizontal saccades was found. The obtained results of experimental studies have shown that despite the completely different physical principles these two methods based on and the presence of measurement errors of different nature, the results of eye movement registration by the VOG and EOG systems are in excellent agreement with each other, on average. The advantage of using the EOG method for measuring saccades and evaluating the vestibular-ocular reflex is shown on this study.