Correction Factor Evaluation and Between-System Comparison of Behavioral Threshold Predictions From Auditory
Marlene Bagatto1, Rana El-Naji1, David Purcell1
1National Centre for Audiology, Western University, London, Ontario, Canada.
Purpose:
Auditory brainstem response (ABR) thresholds are corrected to estimate behavioral thresholds in infants. Corrections were validated, and a comparison of behavioral threshold estimates between systems was conducted to inform equipment transition and protocols in Ontario, Canada.
Method:
In Study 1, a retrospective file review was conducted. ABR threshold estimates from 84 infants with hearing loss were compared to behavioral thresholds to validate the accuracy of the ABR corrections applied in the Ontario Infant Hearing Program since 2016. Study 2 examined the precision of two different ABR systems to estimate thresholds in 37 adult and 105 infant ears.
Results:
Corrected ABR thresholds predicted behavioral thresholds in infants to within 1.77 dB (range of mean values across frequency: 1.18-2.26 dB) on average. The average differences decreased across frequency to 0.6 dB (range: 0.14 to -1.23) when ear canal acoustics were accounted for. The average between-system difference in ABR threshold estimates was 2.40 dB (range: 1.18-2.26).
Conclusions:
ABR correction factors used in Ontario's Infant Hearing Program provide accurate predictions of behavioral thresholds in infants with hearing loss. When calibration and collection parameters are similar between different ABR systems, threshold estimates are comparable and no further adjustment to correction factors was required.
