Comprehensive presentation of semicircular canal sensitivity.

It is generally agreed that in order to determine any difference in vestibular sensitivity between the two inner ears, the best clinical procedure involves a quantitative expression of the slow phase nystagmus response to standardized caloric (or rotatory) stimulation. The preferred procedure has involved averaging the slopes of a few of the nystagmus responses during the period of most intense activity and this has been accomplished either arithmetically or by means of an electronic computer. Although, such a sampling is often sufficient to enable a reliable diagnosis, occasions do arise when the results can be misleading unless comprehensive total presentations of the responses from the two labyrinths are available for reliable comparative evaluation. Such a procedure has been developed at the University of Toronto and used for clinical assessment at St. Michael's Hospital. The reliability of the method has been established as the result of testing over 800 patients with various vestibular disorders.