Electronystagmography (Eye Movement, ENG) Test

Norm of Electronystagmography (Eye Movement, ENG) Test

Normal eye movement free of nystagmus.

 

Usage of Electronystagmography (Eye Movement, ENG) Test

Brain lesion, dizziness (not valuable in community-derived sample of dizzy elderly subjects >65 years old), falls in elderly >65 years of age (best fall indicator is ocular motor battery), unilateral hearing loss, neurotoxicity related to antiepileptic drugs, nystagmus, tinnitus, and vertigo.

 

Description of Electronystagmography (Eye Movement, ENG) Test

Technique for recording eye movements allowing exact quantification of physiologic and pathologic nystagmus. The test picks up subtle spontaneous nystagmus and also helps differentiate peripheral from central nystagmus. The battery of tests includes visual ocular control, the search for pathologic nystagmus with fixation and with eyes open in darkness, and measurement of induced physiologic nystagmus (caloric and rotational). The test can be helpful in identifying a vestibular lesion and localizing it within the peripheral and central pathways. It also provides serial tracings to compare a client's pattern over time.

 

Professional Considerations of Electronystagmography (Eye Movement, ENG) Test

Consent form NOT required.

Risks
Water caloric test: perforation of the eardrum.
Contraindications
In clients with pacemakers or with a perforated eardrum.

 

Preparation

1. None.

 

Procedure

1. Small electrodes are taped to the skin on either side of each eye.
2. Tests include calibration, gaze nystagmus, pendulum tracking, optokinetics, positional tests, and water caloric test.
   • a. Calibration test: The client holds head straight and fixed and follows with the eyes a stylus, from the right side to the middle and then to the left side.
   • b. Gaze nystagmus test: The client must close his or her eyes and perform an arithmetic task for 30 seconds while eye motion is recorded. Then eye motion is recorded with the eyes open and fixed looking straight ahead.
   • c. Pendulum tracking: A 20-second eye motion recording is made as the client looks straight ahead and follows a pendulum with the eyes. This is followed by a 30-second recording of eye motion as the client stares straight ahead with the eyes closed.
   • d. Optokinetics test: Two 30-second recordings of eye motion are made as the client stares straight ahead and then follows a target across the visual field from right to left and then from left to right.
   • e. Positional tests: A 5-second baseline recording of eye motion is obtained, followed by a recording of eye motion as the client follows the following nine commands:
     1. “With head erect and eyes forward, turn your head quickly to the right.”
     2. “With head erect and eyes forward, turn your head quickly to the left.”
     3. “Sit erect with eyes closed and quickly lie flat on your back with your eyes still closed.”
     4. “Sit up quickly from the lying position with your eyes closed.”
     5. “Lie on your back with your eyes closed and quickly turn your body and head to the right.”
     6. “Lie on your back with your eyes closed and turn your body and head to the left.”
     7. “Sit erect with your eyes forward and closed and lay your head back quickly so that it hangs over the back of the chair.”
     8. “Quickly pick up your head from over the back of the chair to the erect position.”
     9. “Quickly put your head back to the right so that it hangs over the back right side of the headrest on the chair and then repeat this by putting your head to the left so that it hangs over the back left side of the headrest on the chair.”
   • f. Water caloric test: The client is positioned at a 30-degree head-of-bed elevation with the eyes closed. Water is instilled directly into the ear canal so that it hits the tympanic membrane, while eye motion is simultaneously recorded. This is followed by a 60-second recording with the eyes open and a final recording with the eyes closed until nystagmus disappears or for 3 minutes.

 

Postprocedure Care

1. Remove electrodes.
2. Assess for dizziness, nausea, or weakness.

 

Client and Family Teaching

1. The test takes less than 1 hour.
2. The client must be cooperative and able to follow commands to ensure the accuracy of the test results.

 

Factors That Affect Results

1. CNS stimulants will increase eye movement, and depressants will decrease eye movement.
2. Poor eyesight.
3. Loose electrodes.
4. Requires considerable cooperation on the part of the client and skill on the part of the operator in conducting and interpreting the test.

 

Other Data

1. Results are reported as normal, borderline, or abnormal.