INTERINTERPRETER VARIABILITY IN DETERMINING THE SP AP RATIO IN CLINICAL ELECTROCOCHLEOGRAPHY/

Calculating the SP/AP ratio in electrocochleography requires the inter preting audiologist to unequivocally identify the peak of the SP wave form. If different points are selected, different SP/AP ratios will re sult. To investigate this effect, 50 electrocochleographic tracings we re sent to 10 different audiologists (500 tracings). Twenty of the wav e forms sent to each audiologist were identified as ''easy,'' 10 as '' somewhat difficult,'' 10 as ''very difficult,'' and 10 as ''no respons e.'' The ranges and standard deviations of the resulting SP/AP ratios were quite high. Analysis of variance showed statistically significant differences in the very difficult and no response group. There is sig nificant interinterpreter difference among SP/AP ratios calculated fro m the same tracing. This variability affects clinical patient manageme nt and investigational projects.