Inter-stimulus interval in audiometry for neonates

The usual paradigm employed for both clinical and experimental evaluation of auditory responsiveness of newborns dictates that signal presentations be separated by a minimum of 15 s. Furthermore, this paradigm requires that there be 8 presentations of the signal and that two responses among the 8 trials should be taken as normal responsiveness. Many have been concerned about accepting 25% as normal, and would prefer a paradigm that could lead to increased responsiveness. A procedure with inter-stimulus intervals longer than 15 s might be that paradigm. Therefore, the following experiment employed inter-stimulus intervals of 15, 30 and 60 s to examine responsiveness of infants young enough to be in a newborn nursery. Each infant received 24 signal presentations (8 with each of the 3 inter-stimulus intervals), and these were counter-balanced across babies. Although there is evidence of response habituation across time, there is also evidence that longer inter-stimulus intervals do lead to increased responsiveness.