Hearing tests based on auditory brain stem responses.

<p><b>A–C</b>) Examples of recordings of auditory brain stem responses to tone bursts of 16 kHz at amplitudes between 0 and 90 dB-SPL that were presented to Tg(+);<i>Slc26a4</i>^+/+ mice at P35 (<b>A</b>), Tg(−);<i>Slc26a4</i>^Δ/Δ mice at P35 (<b>B</b>), and Tg(+);<i>Slc26a4</i>^Δ/Δ mice at P35 (<b>C</b>). Thresholds at 15 dB-SPL are marked (<i>thickened trace</i>). <b>D–L</b>) Hearing thresholds based on auditory brain stem responses, were determined in Tg(+);<i>Slc26a4</i>^Δ/+ mice (<b>D–F</b>), Tg(+);<i>Slc26a4</i>^+/+ mice (<b>G–I</b>), and Tg(+);<i>Slc26a4</i>^Δ/Δ mice (<b>J–L</b>; <i>highlighted in red</i>). Frequencies evaluated at 8 kHz (<b>D, G, J</b>), 16 kHz (<b>E, H, K</b>), and 32 kHz (<b>F, I, L</b>). The combined ranges of normal hearing in the three mouse strains (129S6, C57BL/6 and CBA) that contributed to the background of the mice are marked (<i>grey rectangles</i>). Numbers next to symbols in <b>D–L</b> represent the number of mice tested.