Brainstem response audiometry. I. Its use in distinguishing between conductive and cochlear hearing loss.

The auditory brainstem response thresholds and the latency-level curves, l(L)curves, for peak V were determined in 22 subjects with normal hearing, in 40 patients with conductive hearing loss and in 79 patients with cochlear hearing loss. The goal of this study was to investigate the potentials to distinguish between different types of hearing loss on the basis of these auditory brainstem responses. For this purpose the horizontal shift of the l(L) curve, the horizontal shift of its derivative and the latency of peak V at threshold level were plotted against the response threshold. For response thresholds above 30 dB nHL both the horizontal shift of the l(L) curve and the horizontal shift of its derivative give a good separation between cochlear and conductive hearing loss. The combination of the response threshold with the shift of the derivative of the l(L) curve gave a slightly better separation than that of the response threshold with the shift of the l(L) curve itself.