1. A. B.

2. Supplementary Figure 1. Unaided speech audiometry from proband 1. (A
Supplementary Figure 1. Unaided speech audiometry from proband 1. (A.) The Mainzer child language test at age four years, five months. This test assesses one- and two-syllable words for right ear (left panel) and left ear (right panel). Percent audibility is plotted on the x-axis from zero to 100%. The speech level is represented on the y-axis in dB HL. Proband 1 achieved 20%, 80% and 80% speech recognition at 60 dB HL, 70 dB HL and 80 dB HL, respectively, in the right ear and 20%, 70% and 70% speech recognition at 50 dB HL, 60 dB HL and 65 dB HL, respectively, in the left ear. (B.) The Freiburger speech test at age nine years, three months was performed with insert earphones and foam tips with results appearing as “E” on this test for right ear (left panel) and left ear (right panel). Multi-syllable and monosyllable word recognition scores are marked “Z” and “W,” respectively. Percent audibility is plotted on the x-axis from zero to 100%. The hearing level is represented on the y-axis in dB SPL. These two tests demonstrate a relevant loss of speech understanding.