Automated analysis of bone-conduction cortical auditory evoked potential in normal-hearing neonates

The cortical auditory evoked potential allows the possibility of objectively evaluating the entire auditory system, which is desirable in the pediatric population. Bone conduction auditory stimulation is recommended in the differential diagnosis of conductive hearing loss. However, there are not many studies of cortical auditory evoked potential using bone conduction.

The aim of this study was to characterize the response of cortical auditory evoked potential through bone conduction in normal-hearing neonates using an automated response analysis equipment.

This study included 30 normal-hearing neonates, without risk factors for hearing loss. The equipment used was the HEARlab automated response analysis and the cortical responses were evaluated at the frequencies of 500-4000Hz through bone conduction, at intensity ranging from 0 to 60dBnHL. The latencies and amplitudes were manually marked by experienced judges.

Cortical auditory evoked potential responses were detected in 100% of the evaluated subjects and there was no difference regarding the cortical response of the neonates in relation to the variables of gender, ear and masking use. At an intensity of 60 dBnHL for the frequencies of 500, 1000, 2000 and 4000Hz the latencies were 234; 241; 239 and 253ms and the amplitudes were 15.6; 8.4; 6.2; 6.3μV. The mean thresholds were 23.6; 28; 31 and 33.1dBnHL, respectively.

It was possible to measure the cortical auditory evoked potential response in the neonatal population using bone vibrator as sound transducer and to draw the profile of the cortical auditory evoked potential latencies and amplitudes by frequencies at the intensity of 60dBnHL and at the threshold.