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).