Caloric Inversion

Question

Answer

I assume that what you are describing is an entire caloric response that beats in the opposite direction to that expected (i.e., a left beating nystagmus on a warm right ear irrigation). This is referred to as ''caloric inversion'' and is extremely rare. Caloric inversions have been associated with brain stem disease.

Because caloric inversion is so rare, you must consider a number of sources of error that could cause what appears to be a central abnormality. For instance, if the horizontal electrode leads are plugged in ''in reverse'', the caloric response would appear to be beating in the inverted direction. You should also determine if a strong positional, spontaneous, or congenital nystagmus is present that is beating to the opposite direction of that expected for the caloric response.

As for calculating it in the UW and DP formula, if the inverted response is not the result of a technical error or the result of a pre-existing positional or spontaneous nystagmus, then I would suggest that you use the value arrived at as if it was a normal response., because the presence of a true inverted nystagmus would indicate a central disorder and the presence of a UW or DP may be a moot point.

Bio.

Dr. Trahan is a graduate of LSUHSC with a Masters of Communicative Disorders and a graduate of the University of Florida, Doctor of Audiology

Currently:
Assistant Professor of Audiology at the Arizona School of Health Sciences. Lead faculty for the 4 year AuD Residential program. Currently also teaching vestibular assessment procedures and balance remediation in the ASHS AuD Distance Ed AuD program.

Past:
20 years private practice with significant involvement in assessment of vestibular disorders and vestibular rehabilitation.

Conducted numerous workshops and presentations in regards to audiologists in private practice adding vestibular assessment and vestibular rehabilitation to their practices.