The first two methods use a digital light bar to provide the stimulus. Slow phase velocity is automatically calculated for all nystagmusbased tests as is unilateral weakness, directional preponderance and fixation suppression for the caloric tests. Analysis of the oculomotor tests are also automatically calculated and compared to reference data supplied by the manufacturer. Saves time, reduces costs and eliminates electrical and myogenic interference since electrodes are not used. Display and videotaping of eye movement allows for the observation and documentation of unusual yet pathologically significant eye movement such as torsional or rotatory nystagmus.
Test validity is enhanced since the entire test is performed with eyes open.
The video display portion of the system can be used during canolith repositioning maneuvers to document, via observaton and videotaping, the success of the treatment. Several manufacturers of diagnostic video eye tracing systems also have less expensive instruments for observing and videotaping eye movement during routine physical examinations. For example, many physicians perform the Dix-Hallpike maneuver during intitial history and physical examination. Since the test is performed with eyes open, so the examiner can view the eyes for any sign of abnormal movement, the patient can often suppress the nystagmus by fixating on something in the environment. Standard frenzel lenses improve the chances of observing abnormal eye movement but do not completely eliminate the chance for fixation suppression.