Question
I recently performed a VNG where everything was normal except for an abnormal gain and morphology for slow and fast sinusoidal tracking, diminished gain values for slow and fast OPK testing, and a caloric inversion for only the right warm irrigation. All other aspects of the testing were normal. I double checked my testing procedures and know that I was irrigating the correct ear with the warm air. I reported this as an abnormal test suggesting central pathology. I would like to know if my assessment is correct.
Answer
Abnormal tracking and optokinetic nystagmus denote central nervous system dysfunction. A caloric inversion for only the right warm irrigation is hard to explain. It is likely due to a testing error, such as an inadequate right warm irrigation in the presence of left-beating spontaneous nystagmus. I would have to see your test data to be sure.
Bio:
Charles W. Stockwell, Ph.D., is president of Charles W. Stockwell & Associates. His professional career spans academia and clinical practice. Dr. Stockwell has written two books, Manual of Electronystagmography and ENG Workbook, as well as a number of book chapters and scientific papers in peer-reviewed journals.
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