Assessment [RETIRED]

Strictly speaking, the term electronystagmography refers to the recording of ocular nystagmus using electrooculography. However, electronystagmography has come to mean recording of eye movements, nystagmoid or otherwise, in various circumstances and in response to vestibular, visual, cervical, caloric, rotational, or positional stimulation. [1-3] Typically, electrooculography is the method used to record eye movement during electronystagmography. However, other methods for recording eye movement, especially when used to record nystagmoid eye movements, also have been labeled as electronystagmography.'' Since the specific method of recording eye movement is not nearly as critical as the type of eye movement being recorded, it is likely that future techniques using computer-aided analysis of video images of eye movements will also be labeled electronystagmography. Indeed, commercial computer video-based eye movement recording systems have been termed video-ENG'' (ENG is commonly used synonymously with electronystagmography). The earliest English-language description of electronystagmography is found in the neurology literature. [4] However, the neurology community only recently has become interested in electronystagmography and vestibular function assessment. Electronystagmography has been the concern of the otolaryngologist and, as such, most electronystagmography testing is performed and interpreted by these specialists. The American Academy of Neurology's need for a technology assessment of electronystagmography was engendered by a recent surge in the neurology community's interest regarding these techniques and a lack of unanimity of opinion regarding its usefulness. This assessment applies only to adult, and not pediatric, vestibular testing. Eye movement recordings during electronystagmography typically are based upon electrooculography using either monocular or binocular recordings. Calibration is usually accomplished by asking the patient to look at targets that are placed in the primary position and at 10 degrees or 15 degrees horizontally. Using the calibration, a relationship between eye position and electrooculographic voltage can be obtained, thereby allowing quantification of the patient's eye movements. If the eyes …