Experiences with a computer-based electronystagmography system in examining totally deaf patients.

A lthough the computer-based electronystagmography (ENG) system's analytic routines offer refinements available only in research laboratories, the system is very useful also in everyday practice. The computer-based ENG system contains a stimulator for saccadic and sinusoidal eye movements and for optokinetic eye movements, both of which are connected to the registration program. The system contains software for the numerical analysis of nystagmus, especially slowphase velocity. When stimulation begins, registration also starts automatically. The system can save patient data. Connected to the computer system is an air caloric stimulator used by the authors for the examination of caloric nystagmus. With this stimulator, caloric irrigation is safe also in cases of a perforated eardrum or even in ears that have been operated on. The tirrilng of irrigation and the temperature of the air can be defined. The caloric stimulator is shaped similarly to an otoscope; using it is very easy. The advantages of the computer-based ENG system are evident: A quantitative and qualitative analysis of nystagmus parameters can be made. Patient data can be saved for the control examinations, so the changes in the vestibular status can be monitored. Finally, the system is available for scientific analysis of nystagmus. Every method also has disadvantages: Examination by computer-based ENG requires hardware and software, so it is very expensive. A complete examination takes perhaps an hour, and the cooperation of the patient is essential. The system cannot register every symptom and sign