2.1 Participants
Eleven children (mean: 7.45 years, standard deviation [SD]: 1.81 years) who had UMA and experienced congenital UCHL were included. All patients had normal hearing (NH) in one ear (hearing thresholds of ≤ 25 dB HL across 0.5–4 kHz) and pure conductive hearing loss in the impaired ear (air-bone gap of ≥ 25 dB HL, with bone conduction thresholds of ≤ 25 dB HL across 0.25–4 kHz). Eleven children who had bilateral NH were recruited as controls. Detailed demographic data are summarized in Table 1.