OBJECTIVE To investigate the feasibility of determining the maximum comfortabl level by using the acoustically evoked stapedius reflex threshold via cochlear implant. METHODS Eleve cases of Nucleus C124 cochlear implant recipients operated in our hospital were selected(8-39 years old, who can decide TIC value by themselves with the postoperative time ranging from device initiation to 1 year after operation),of those four cases were diagnosed as bilateral large vestibular aqueduct syndrome,1 case as common cavity dysplasia,.neural response telemetry of these five patients with inner ear dysplasia were very high or barely measurable.Real-MCL level and acoustically evoked stapedius reflex threshold under activated condition were measured respectively. The stimulating sound was 110dB of white noise.RESULTS The two group values of ASRT and real-MCL were found to be consistant .There is no significant difference statistically (P＞0.05). The thresholds of ASR increase with the increasing of real-MCL at the beginning of device initiation. CONCLUSION The acoustically evoked stapedius reflex threshold may reflect (ASRT) the maximum comfortable stimulation level under activated conditions in patients with cochlear implants.it is simple, reliable and may be used to determine the MCL of child cochlear implanted patients.

OBJECTIVE To find the best way to evaluate the hearing threshold with the objectivethresholds of auditory brainstem response(ABR) and 40Hz auditory event related potential(40Hz AERP) . METHODS Pure tone audiometry,ABR and 40Hz AERP detection were performed in 120 recipients from whom 86 ears were available to be analyzed. According to the styles of configuration of hearing,we divided the 86 ears into 3 groups. There were 37 ears in flat style group,29 ears in descent style group,20 ears in ascent style group. The values were statistically analyzed with SPSS software. Correlations and multiple linear regression analysis were used in each group separately and three kind of mathematic models were established to estimate the subjective auditory thresholds. Then the models were simplified and tested. At last the models were checked out in 10 new recipients separately. RESULTS The pure tone audiometric threshold had good liner correlations with ABR and 40Hz AERP in three groups(R2=0.932,0.944,0.934) . In the flat style group,the subjective average auditory threshold can be estimated by ABR threshold. The predict mathematic model of the descent style group was 1/3(40HzAERP) +2/3ABR and the model of the ascent style group was 2/3(40HzAERP) +1/3ABR. Mean square deviation test showed equation manners were better than ABR means. CONCLUSION We can predict the subjective average auditory threshold more accurately than ABR only from ABR threshold and 40Hz AERP values with the predict mathematic models in young child and patients difficult to be test with subjective audiometry.