Electronystagmography is a 90-minute medical test where a doctor will measure a patient's eye movements with electrodes in response to various stimuli. A common reason to request this test is a suspected balance disorder, where the doctor wants to collect information about how well the patient's vestibular system works. The eyes are part of this system, providing feedback about where the body is in space. Patients with pathologic nystagmus, where involuntary eye movements cause problems, may also receive an evaluation with this method.
During an electronystagmography, the patient remains fully dressed and lies on an exam table. At various points in the test, the patient will need to change position. A doctor can fix electrodes around the eye to record electrical impulses, or may have the patient wear goggles with a camera inside. The camera will track eye movements and record data.
At various phases in the test, the doctor will provide the patient with stimuli and record the response. One technique is the application of cold or warm water or air to the ear. The eyes should jerk away from the ear when the water is cold, and leap toward it when the water is hot. Patients can also track dots and other visual stimuli with their eyes. The doctor may have the patient perform tasks while sitting, lying, and standing to see how the patient's vestibular system responds to these different positions.
Receiving an electronystagmography test is not invasive and the procedure is low risk, unless the patient has a history of seizures. People with seizure disorders may need modifications to the test, as flashing lights can trigger seizure activity. Patients may express discomfort with the goggles or electrodes, but they should not be painful. As soon as the electronystagmography session is over, the patient can go home.
Depending on why a doctor requested electronystagmography, it may take several days to get results. A doctor or technician must analyze the data and determine what it means. Abnormal results do not necessarily mean there is something wrong, but may be cause for further testing and evaluation. The patient will receive a call when the results are in, and may need to go to the doctor to discuss them if they are complex. Patients should remember that a request to go to the doctor's office does not mean results are bad. Sometimes the doctor wants to explain them in person or wishes to conduct another test.