2.31|Auditory Evaluation
Comprehensive audiological evaluations were performed by trained professional staffs in our hearing center. Behavior audiometry was obtained with TDH-39P earphones (Interacoustics, AD229e) with the maximum output of 120dB HL in the frequency of 500-4000Hz and 110dB HL in the frequency of 250 and 8000Hz bilaterally. Auditory steady-state response (ASSR) was obtained with TDH-39P earphones (Interacoustics, Eclipse) with the maximum output of 100dB nHL bilaterally. Better ear hearing threshold was calculated for the thresholds of 500, 1000, 2000, and 4000Hz, with a value of 5dB over the limit at the frequency used as the calculation for no response thresholds(19). The difference between binaural hearing was calculated by the results of ASSR. If the difference was no more than10 dB nHL, we defined it symmetry of binaural hearing; if it was more than10 dB nHL, we thought it asymmetry(20).