# Pitfalls in the Detection of Hearing Loss via Otoacoustic Emissions
## 3 Results
### Accu 1 and Accu 2 Outcomes in Relation to Hearing Thresholds  
Based on the audiometric data from each tested ear, it was possible to define three frequency ranges for hearing thresholds >25 dB, as in the scheme below:  
* low frequency range: 0.125-0.5 kHz;
* mid-frequency range: 1-4 kHz;
* high frequency range: 8 kHz.  
Test results for the ears were as follows: 10 ears above 25 dB only at mid-frequencies; 12 ears above 25 dB only at high frequencies; 1 ear above 25 dB at both low and high frequencies; 61 ears above 25 dB at both mid and high frequencies; 40 ears above 25 dB for all three ranges; and 61 ears where the hearing threshold was not elevated >25 dB for any of the three frequency ranges. Table 2 shows how the devices classified these ears (i.e., pass or refer).  
As can be seen in Table 2, both Accuscreen devices performed best when an ear presented simultaneous threshold elevation in all three frequency ranges. The Accu 2 was especially efficient in properly identifying these ears (82.5% refer rate). Accu 2  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**Hearing Threshold Elevated at**} & \multicolumn{2}{c}{**Accu 1**} & \multicolumn{2}{c}{**Accu 2**} \\ \cline{2-5}  & **Pass** & **Refer** & **Pass** & **Refer** \\ \hline Only mid & 8 (80.0) & 2 (20.0) & 6 (60.0) & 4 (40.0) \\ Only high & 11 (91.7) & 1 (8.3) & 9 (75.0) & 3 (25.0) \\ Low+high & 1 (100) & 0 & 1 (100) & 0 \\ Mid+high & 45 (73.8) & 16 (26.2) & 24 (39.3) & 37 (60.7) \\ Low+mid+high & 14 (35.0) & 26 (65.0) & 7 (17.5) & 33 (82.5) \\ All frequencies below 25 dB & 60 (98.4) & 1 (1.6) & 50 (82.0) & 11 (18.0) \\ \hline \hline \end{tabular}
\end{table}
Table 2: Pass and refer rates of both Accuscreen devices in ears with hearing thresholds above 25 dB at low and/or mid and/or high frequencies. Number of ears and percent values (in parentheses) are given.  
Figure 1: Average pure tone audiometry (PTA) thresholds (**A**) and average signal-to-noise ratio (SNR) (**B**) of transiently evoked otoacoustic emissions (TEOAEs) as measured by the ILO device for three groups: refer–refer, pass–pass, and pass–refer.  
also performed fairly well in cases presenting a threshold elevation in the mid and high frequency ranges. The refer rate for Accu 2 was 60.7%, while the corresponding rate for the Accu 1 was 26.2%.  
Both devices performed worst in ears where only the 8 kHz frequency threshold was \(>\)25 dB. The Accu 2 gave a 25% refer rate and the Accu 1 an 8.3% refer rate. These observations form indirect evidence suggesting that the Accuscreen probes have a rather narrow frequency response (capturing information mainly from the 1-2 kHz range).  
The agreement (refer-refer, pass-pass, pass-refer) between the Accuscreen devices in classifying ears with hearing thresholds above 25 dB was also evaluated. These results are summarized in Table 3.  
Table 3 shows that disagreement occurred most frequently in relation to ears with elevated thresholds in the mid and high frequency ranges, i.e., 34.4% of these ears received different assessments. Additionally, 39.3% of these ears (presenting threshold elevations in the mid and high frequency ranges) were classified by both devices as pass-pass cases, and only 26.2% were classified as refer-refer. Both Acuscreen devices classified the majority of ears having only a threshold elevation in the mid or high frequency range as pass-pass cases (60% and 75%, respectively); it is possible that there was a situation where substantial agreement ensued, but such consistency is questionable (i.e., it is more likely that both devices had difficulty recognizing the problem).