Experiences with the butterfly chart.

The bithermal caloric test remains, four decades after its first description, the single most valuable test of vestibular function. However, there are several variations described in the exact procedure of caloric stimulation and in the method of evaluating and representing the test results. For the past 10 years, we have followed a procedure using a constant standardized stimulus and a particular system for caloric nystagmus representation, viz., the Butterfly Chart, and have found it to be very satisfactory. This paper describes our experience with the use of the Butterfly Chart and its clinical application in over 4,500 cases.