CLINICIANS using electronystagmography (ENG) for evaluation of vestibular function, should have instruments that are portable, not expansive, simple to operate, and provide recordings with minimal drifting and artifacts. Obviously the stimulus to induce nystagmus must remain constant from patient to patient. With this purpose the following equipment has been designed.
Two Channel ENG Recorder (Fig 1).— It has the following basic features: (1) selfcontained portable unit; (2) direct and velocity nystagmus channel requiring no external amplification; (3) pushbutton paper speed control (2.5, 5, 10, 20 mm/sec); (4) time marker (1 sec) and audio indicator; (5) external event marker; (6) automatic room "lights out" marker; (7) pushbutton ink primer; (8) z-fold paper; (9) nystagmus velocity fast/slow selector switch; and (10) biopotential electrodes.
The direct channel of the recorder displays eye position or direct nystagmus. The second channel, the velocity of the nystagmus. By means of a selector switch, one can