Evaluating auditory pathway by promontory stimulation test and postoperative hearing rehabilitation(28 cases)

Abstract

Objective:Objective:〖WT〗To evaluate auditory pathway in patients by promontory stimulation test(PST) before artificial cochlear implantation(CI), and to analyze the relationship between postoperative hearing rehabilitation and PST. Method:Selecting 28 cases of adult subjects without residual hearing who accepted promontory stimulation test, different etiology led to bilateral severe sensor neural deafness. PST was examined by measuring the electric auditory threshold(T value) and maximum comfort threshold(M value) of 50, 100 and 200 Hz pulse square waves, and by measuring frequency discrimination. Cochlear implantation was performed in 22 patients detected electrical hearing. NRT and speech perception of disyllabic words were tested 12 months later. The data was analyzed by statistically. Result:Twenty-two patients could be detected, the average T value of PST of 100 and 200 Hz:(14.21±12.86) μA, (20.37±19.19) μA, M value: (33.88 ±21.79) μA, (47.92±28.93) μA, the dynamic range: (21.18±14.15) μA, (27.55±20.40) μA. 14 patients can distinguish the frequency difference. 22 patients accepted hearing 1 month after surgery. The average hearing threshold at 12 months is(25.87±2.35) dB to(41.27±4.55) dB. The average speech perception rate at 12 months is(74.37±15.19)% in quiet environment, and it was significantly difference(P<0.05) between two groups in frequency discrimination ability. Postoperative speech perception outcome correlated with the dynamic range of the PST at 100 and 200 Hz, and the T value of 100 Hz and the T and M values of 200 Hz, there were statistically significant difference(P<0.05). Conclusion:PST can be used to evaluate the auditory pathway in difficult cases before cochlear implantation, and to predict functional outcome after cochlear implant surgery.