[Identification of the waveform of cortical auditory evoked potentials]

Slow vertex response (SVR) audiometry is presently one of the methods of choice in objective auditory threshold assessment. The aim of this study, carried out on twenty subjects with various degrees and types of hearing loss, was to evaluate the difficulties found in N1P2 complex identification. Tracings, presented as single averages and super-imposed averages, were examined separately by two Authors who had not been received any information concerning the audiometric thresholds of the subjects under investigation. Results showed that erroneous identification of SVR waveforms occurred frequently, especially near threshold level. The rate of false negatives (i.e. a waveform present but not identified) was higher than the rate of false positives (i.e. erroneous identification of a non-existing N1P2 complex). High intra- and interindividual discrepancies were also found. Our results appear to indicate that the SVR waveform is not easily identifiable and thus that SVR audiometry cannot, therefore, be considered a truly objective audiometric test since analysis of the tracings may be influenced by the high degree of variability in individual interpretation.