The Clinical Evaluation of a Modified Fmp in Infant Auditory Brainstem Response Tests
Guy Lightfoot1, Constantina Georga2, Inga Ferm3
1ERA Training & Consultancy Ltd, Wirral, United Kingdom.
Objective:
The performance of a modified calculation of F statistic using multiple points (Fmp) in auditory brainstem response (ABR) tests in infants was evaluated.
Design:
Using UK national guidelines, the ABR threshold was established on 50 infant ears at 4 kHz and 41 infant ears at 1 kHz. A specificity-based Fmp criterion for response presence was established from the distribution of no-response values. This criterion was then applied to determine the sensitivity of Fmp in detecting responses.
Results:
A 97.5% true negative rate in no-response waveforms corresponded to an Fmp of 2.2. This criterion detected 85% of 4 kHz and 68% of 1 kHz responses at 10 dB above the ABR threshold but only 51% of 4 kHz and 32% of 1 kHz responses at the ABR threshold.
Conclusions:
Fmp has reasonable clinical utility at stimulus levels above the ABR threshold but is not an adequate replacement for strictly applied conventional waveform interpretation at the ABR threshold. A proposal is offered that should improve Fmp sensitivity.
