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Table 1 Some differences between EOG and VOG

From: Methods considerations for nystagmography

  ELECTRO-oculography (EOG) VIDEO-oculography (VOG)
Entity measured Corneo-retinal electrical potential Digitized position of a black circle presumed to be the pupil
Drift Shift of baseline if DC recording used. Theoretically no shift
Variable if AC recording
Artifact Eye blinks and muscle contraction are the most frequent artifacts Dark features such as mascara, closed eyes, eye brows “fool” the system momentarily.
Eye blinks, difficulty detecting the pupil causes large artifacts
Sampling rates While most commercial units sample calorics at 30 Hz, much higher sampling rates are feasible. This is critical for accurate measurement of quick phases Video sampling rates are usually 30–60 Hz. Sampling rates of 100 Hz requires specialized equipment.
Ease of use Sticky electrodes are required with possible impedance problems, electrical drift and small signal The patient wears goggles to mount the camera to, which limits eye displacement to approximately 20°
Determination of maximum slow phase velocity (SPEV) Maximum average SPEV of the three greatest consecutive beats Maximum average SPEV for a 10 s window of recording