# Distortion-product Otoacoustic Emissions in Diagnostic Versus Portable Equipment: A Comparison of Animal Models

## TL;DR

This study compares diagnostic and portable equipment for measuring hearing in rats, finding similar results at higher frequencies.

## Contribution

The study evaluates the consistency of otoacoustic emission measurements between diagnostic and portable devices in animal models.

## Key findings

- At 6 and 8 kHz, no significant difference was found in signal-to-noise ratios between diagnostic and portable equipment.
- 100% agreement was observed when classifying data as normal or abnormal across both methodologies.
- Portable equipment showed lower amplitude values compared to diagnostic equipment at all tested frequencies.

## Abstract

Introduction
 Many protocols carried out in animal studies use equipment developed for humans. Therefore, the equipment available on the market must be known in detail, as well as how the criteria to be evaluated are presented.

Objective
 To analyze the existence of an association between the amplitude and signal-to-noise ratios of distortion-product otoacoustic emissions using two methodologies (diagnostic and portable/screening equipment) in animal models.

Methods
 Experimental study approved by the Animal Use Ethics Committee, with a sample of 28 female Wistar rats, which were subjected to anesthesia, manual otoscopy, and distortion-product otoacoustic emission (DPOAE) examination at 4 to 8 kHz with the 2 pieces of equipment.

Results
 The mean amplitude values with the ILO (Otodynamics Ltd., Hatfield, United Kingdom) and OtoRead equipment (Interacoustics A/S, Middelfart, Denmark) were respectively 20.5 dB and 7.1 dB at 4 kHz; 31.8 dB and 19.37 dB at 6 kHz; and 31.4 dB and 25.1 dB at 8 kHz. The mean signal-to-noise ratios with the ILO and OtoRead equipment were respectively 20.9 dB and 25.1 dB at 4 kHz; 35.8 dB and 37.0 dB at 6 kHz; and 39.7 dB and 40.6 dB at 8 kHz. There was no statistically significant difference in signal-to-noise ratios at 6 and 8 kHz. When the data were classified as normal/abnormal, 100% agreement was found between the methodologies.

Conclusion
 An association was found in the analysis of the mean signal-to-noise ratio at 6 and 8 kHz between the 2 methodologies (diagnosis and portable/screening equipment).