Objective: In this study, we aimed to establish a frequency-specific ABR (fs-ABR) system via loudspeakers to assess the hearing improvement in ossiculoplasty intra-operatively and observe its efficiency and accuracy in predicting the long-term outcome. Setting Blackman-gated 1kHz tone-pips with 1ms, 2ms and 3ms duration were used in normal hearing (NH) subjects to calibrate the system and the standard ABR threshold and wave V latency for this system were established. All subjects would take four hearing tests: Pure tone audiometry (PTA) before and six-month after the surgery, fs-ABR under anesthesia before surgery and right after the ossicular chain reconstruction intra-operatively. PTA was used as the standard test to measure hearing. Bland-Altman analysis and linear correlation analysis were used to compare the agreement between PTA and fs-ABR results. Participants Forty-two conductive hearing loss (CHL) subjects. Results: For NH and CHL subjects in operating room before surgery, the fs-ABR threshold showed a high linear relation with the PTA results (r=0.88, P<.0001). For CHL follow up results: for 1ms group, PTAI showed a better correlation with fs-ABRI (r=0.67, P<.01) with the equation: PTAI=2.15*fs-ABRI-3.49; for 3ms group, PTA showed a better correlation with fs-ABR (r=0.76, P<.01) with the equation PTA=0.93*fs-ABR+3.48. Bland-Altman analysis showed no difference between PTA and fs-ABR in all above analysis. Eustachian tube malfunction would negatively affect the prediction efficacy, for subjects with normal ETF, the correlation between fs-ABRI and PTAI was even higher: PTAI=1.6*fs-ABRI+12.48 with r=0.77 (P=.0407<0.05). Conclusions This system could monitor the function of the reconstructed ossicular chain intra-operatively and predict the post-surgical 6-month hearing improvement efficiently and accurately. The average testing time for the fs-ABR was short, about 10 to 15 minutes. This system would serve as a promising tool clinically to help surgeons optimize the efficacy of ossiculoplasty. Besides, ETF should be taken into consideration as a risk factor that would negatively influence the hearing impairment.

Background: Waardenburg syndrome (WS), a common type of syndromic hearing loss. A large group of patients affected by WS were found no mutations in the above gene panel, indicating that there are still potential genes responsible for WS yet to be detected. Methods: In our previous study, we established a KITD806E/+ pig pedigree with an autosomal dominant inheritance model. This model presented congenital bilateral severe sensorineural hearing loss with hypopigmentation, exact the same as human WS. Results: Histological analysis of the KITD806E/+ cochlea showed nearly normal structures of the organ of Corti, stria vascularis and spiral neuron ganglions at E85. Scanning electron microscopy (SEM) exhibited the auditory hair cells began to degenerate at E100, and totally gone at P1. Transmission electron microscope (TEM) showed disorganization of stria vascularis (SV) and intermediate cells in the middle layer of SV had gone. The absence of endocochlear potentials also demonstrated the dysfunction of stria. Conclusions: KITD806E/+ mutation interrupted the development of melanocytes in cochlea, which led to the malformation and dysfunction of SV, resulting in degeneration of hair cells and finally hearing loss. Therefore, KIT was highly supposed to be a newly found gene associated with WS.