The percentage changes in ASR_P–P, ASR_RMS, ASR_DUR and A_LAT as the function of frequency difference (Δ<i>f</i>) when the background frequency was 10 kHz.

<p> The pattern is similar to those with an 18 kHz background frequency. The gray areas represent the corresponding areas of the standard deviation in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0045123#pone-0045123-g004" target="_blank">Figure 4</a>.</p

ASR with different background sounds.

<p>An example of ASR elicited with a 100 dB SPL white noise burst in the presence of a continuous background tone of 18 kHz at 70 dB SPL (A). Normalized ASR in the presence of no background, white noise, 6 kHz, 10 kHz, 12 kHz, 18 kHz, and 26 kHz (B). ASR was significant smaller for frequency 10 kHz and above than that with white noise background. No significant difference in ASR was demonstrated in the range from 10–26 kHz background frequencies. N: no background sound; S: startle stimulus; W: white noise.</p

The threshold of auditory brainstem response as a function of tone frequency.

<p>The thresholds were significantly lower in responses to 9 kHz, 13.5 kHz and 20.25 kHz than in responses to 4 kHz, 6 kHz and 30.8 kHz (p<0.001). The difference in the thresholds for 9 kHz and 20.25 kHz tones were statistically insignificant, indicating similar hearing sensitivity between the two frequencies.</p