ENG

electronystagmography

VNG

Videonystagmography

What is EOG measuring?

measures the changes in voltage due to eye movement

What is VOG measuring?

use of infrared light sensors to detect eye movement

Horizontal channel

Right eye movement is shown as an upward pen tracing

Left eye movement is shown as a downward pen tracing

Vertical channel

Upward eye movement is shown as an upward movement of the pen

Downward eye movement is shown as a downward movement of the pen

Benefits to ENG

Initially less expensive

Can record a larger number degrees of eye movement

can be used for certain populations (individuals with droopy eyelids, those who can’t keep eyes open, children younger than 5)

Drawbacks to ENG

affected by ambient light (needing frequency recalibration)

affected by retinal pathology

eye blink artifact

less accurate measuring vertical eye movement,

not sensitive to torsional eye movement,

Bell’s Phenomenon, and DC drift.

Benefits to VNG

Does not require electrodes

can video record movements for later analysis

easier to monitor eye movements while testing

easier to measure individual eye movements (if bilateral recordings)

Drawbacks to VNG

Narrow angular range

can’t be measured with eyes closed

size and weight of goggles

can be affected by eye makeup.

What is the potential we are measuring for ENG?

Uses EOG to record eye movements during a series of tests designed to assess the function of the vestibular and oculomtor systems. EOG is recording of changes in DC voltage that is caused by the eye movements