On the single sweep processing of auditory brainstem responses: click vs. chirp stimulations and active vs. passive electrodes

On the objective assessment of the auditory brainstem response measurement quality

Auditory Brainstem Responses (ABRs) are commonly used in clinical practice to determine hearing impairments and hearing thresholds. Although many research groups work on automatic recognition of ABRs - in order to decrease the acquisition times - measures to determine the quality of ABR measurements objectively are still missing. In fact, recently released new standards for electroencephalographic measurements in auditory examinations require an objective measurement quality assessment for neurodiagnostic devices. Thus there is a pressing need for the development and evaluation of such a quality control. In this study, we propose (a) a novel technique for the assessment of the ABR measurement quality and (b) evaluate and compare this technique to two other approaches which have been suggested in literature as required by the new standards.

Habituation analysis of chirp vs. tone evoked auditory late responses

We have recently shown that tone evoked auditory late responses are able to proof that habituation is occurring [1], [2]. The sweep to sweep analysis using time scale coherence method from [1] is used. Where clear results using tone evoked ALRs were obtained. Now it is of interest how does the results behave using chirp evoked ALRs compared to tone evoked ALRs so that basilar membrane dispersion is compensated. We presented three different tone bursts and three different band limited chirps to 10 subjects using two different loudness levels which the subjects determined themselves before as medium and uncomfortably loud. The 3 chirps are band limited within 3 different ranges, the chirp with the lowest center frequency has the smallest range (according to octave-band). Chirps and tone bursts are using the same center frequencies.

A series of notched-noise embedded chirps for objective frequency specific hearing examinations

Chirp-evoked auditory brainstem responses (ABRs) have shown a better performance compared to click-evoked ABRs, due to their temporal organization which compensates for the traveling wave delay achieving a synchronous discharge of the cochlea. In this paper we present the development and evaluation, in healthy subjects, of a series of notched noise embedded frequency specific chirps to evoke ABRs. Results of the ABRs using Phase Synchronization Stability are also reported. The assessment of frequency specific responses by using noise embedded chirps was possible, and the PSS analysis supported previous findings which stated that low frequency channels are better for the recognition and analysis of chirp-evoked ABRs. Accordingly, future analysis can be done to make a faster recognition of frequency specific chirps-evoked ABRs.