Middle latency and 40 Hz auditory evoked responses in normal hearing children: 500 Hz thresholds.

The 500 Hz tone burst thresholds were obtained by four independent judges from recorded middle latency responses (MLR) and 40 Hz event related potentials (40 Hz ERP) in a group of children ranging in age from 5-12 years old. The thresholds obtained from the two electrophysiological methods were compared to each other and to behavioural pure-tone thresholds by means of a paired t-tests. The general trend was for the MLR thresholds to be lower than 40 Hz ERP thresholds. However, the statistical analysis indicated that the differences between the two electrophysiologic thresholds and pure-tone audiometric thresholds were not significant. It was concluded that MLR and 40 Hz ERP under the conditions in which this study was done are not suitable electrophysiological measurements in order to estimate the low frequency thresholds in children.