Input and output compensation for the cochlear traveling wave delay in wide-band ABR recordings: implications for small acoustic tumor detection.

BACKGROUND The Stacked ABR (auditory brainstem response) attempts at the output of the auditory periphery to compensate for the temporal dispersion of neural activation caused by the cochlear traveling wave in response to click stimulation. Compensation can also be made at the input by using a chirp stimulus. It has been demonstrated that the Stacked ABR is sensitive to small tumors that are often missed by standard ABR latency measures. PURPOSE Because a chirp stimulus requires only a single data acquisition run whereas the Stacked ABR requires six, we try to evaluate some indirect evidence justifying the use of a chirp for small tumor detection. RESEARCH DESIGN We compared the sensitivity and specificity of different Stacked ABRs formed by aligning the derived-band ABRs according to (1) the individual's peak latencies, (2) the group mean latencies, and (3) the modeled latencies used to develop a chirp. RESULTS For tumor detection with a chosen sensitivity of 95%, a relatively high specificity of 85% may be achieved with a chirp. CONCLUSION It appears worthwhile to explore the actual use of a chirp because significantly shorter test and analysis times might be possible.