Question
Can you please address the following four issues relating to up/down nystagmus?
1- Is up beating nystagmus only seen in the up or down gaze test?
2- Is down beating nystagmus only seen on lateral gaze?
3- Is it possible to see the up or down beating nystagmus in any part of the ENG evaluation?
4- If so, what does it mean?
Answer
1- Is up beating nystagmus only seen in the up or down gaze test?
No. Up beating nystagmus is usually present with eyes open at center gaze, but is often exacerbated by upward gaze and sometimes by downward gaze.
2- Is down beating nystagmus only seen on lateral gaze?
No. Down beating nystagmus is usually present with eyes open at center gaze, but may be exacerbated by lateral or downward gaze and by lying backward. If down beating nystagmus is weak, it may not be seen on center gaze and may appear only on lateral or downward gaze. If it is very weak, it may not be seen at all during the gaze test and may appear only after the Dix-Hallpike maneuver.
3- Is it possible to see the up or down beating nystagmus in any part of the ENG evaluation?
Yes. Up or down beating nystagmus can appear in various parts of the ENG evaluation, as described above.
4- If so, what does it mean?
Up beating nystagmus is caused by a lesion of the medulla or anterior vermis of the cerebellum. Etiologies include infarctions, tumors, degenerations, and atrophies of the cerebellum, medulla and midbrain, and multiple sclerosis. Down beating nystagmus is caused by a lesion of the vestibulocerebellum and underlying medulla. Etiologies include cerebellar degeneration, craniocervical anomalies, and brain stem infarction.
Bio:
Charles W. Stockwell, Ph.D., earned his doctorate in psychology at the University of Illinois in 1968. Currently president of Charles W. Stockwell & Associates, a consulting firm he established in 1990, Dr. Stockwell's professional career spans academia and clinical practice. From 1986 to 1996, he was director of the vestibular laboratory at Providence Hospital in Southfield, Michigan. Prior to that, Dr. Stockwell was a professor in the departments of otolaryngology and audiology at Wayne State University, in Detroit. And, from 1972 through 1884, he advanced from assistant professor to professor in the departments of otolaryngology and communication at Ohio State University. Dr. Stockwell has authored two books, Manual of Electronystagmography and ENG Workbook, and contributed chapters to numerous others. He has published more than 40 papers in peer-reviewed journals and conference proceedings and has made more than 120 presentations at scientific meetings or continuing medical education courses.
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