Auditory brainstem response: recent developments in recording and analysis.

During the past 25 years since the 'discovery' of the ABR, clinicians world-wide have exploited the clinical utility of this evoked response with many different populations. The 1970s and 1980s saw the development of ABR protocols for increasing the reliability and validity of the response in various clinical situations. Now, in the last decade of the century, advanced technology and the development of increasingly sophisticated software allows more flexibility in these measurements. Thus, ABR testing continues to evolve at a rapid pace. The main focus for ABR in the 1990s has been on developing techniques to improve the quality of the response, decrease the time in which it takes to record the response, and minimize human error through objective response analysis. Some of the major recent developments were reviewed in this chapter. The intent of this review is to provide the researcher and the clinician with an understanding of the underlying principles of the techniques which will be, and are already, available to them on their ABR equipment. Many of these techniques are promising for use with newborns, children, and difficult-to-test populations where time is a limiting factor in the amount of information that can be obtained. We encourage any and all clinicians to experiment with these techniques to determine how each technique might contribute to their particular clinic protocols. As with any new technique, there will be a learning curve associated with understanding the underlying principles, mastering the technical requirements, and realizing the most valuable clinical applications of these methods. Once the procedures become familiar to clinicians and applied in varied clinical settings, it is likely that the neurodiagnostic and audiologic value of ABR will be profoundly enhanced.