Visual and Other Factors Influencing Caloric Nystagmus in Normal Subjects

Abstract

Clinical experience has shown that the response to caloric stimulation may vary in the same person when the test is performed by different examiners, or even when the test is performed in the same manner by the same examiner on different days. The interindividual variations in response to caloric tests are even more striking.¹ This apparent inconsistency of response detracts greatly from the clinical usefulness of the caloric test. For this reason we set out to find factors that account for this variability of the caloric response, hoping that by a better understanding of these factors methods might be devised whereby caloric testing would produce more consistent results in practice. It is immediately apparent that certain anatomic differences exist between persons that could account for their failure to respond to caloric stimulation in precisely the same manner. These include differences in the structure of the temporal bone and the