Auditory steady-state responses--rate effects across adult lifespan

Veterans Health Administration, Decatur PA

Investigators

Abstract

DESCRIPTION The transient-evoked potential-analysis approach provides a broadly accepted way to identify and measure component auditory evoked potentials (AEPs). However, for purposes of looking across normal brain development/aging, there is a need for a paradigm shift toward a process that objectifies AEP interpretation. Toward this goal, a shift toward a more analytical method to the evoked response has been developed from the use of a steady-state-analysis approach, which potentially provides a more analytical and objective approach and whose advantages may well serve such interests as tracking aging changes and/or effects of brain injury, that is- if the approach is extended to incorporate a more comprehensive representation of the AEP component waves. This new method has been applied, and findings in young children and adults demonstrate efficacy of the method, namely in a unified test and analysis, rather than several different transient tests with response identification and measurement more-or-less idiosyncratic to each component test. The proposed study builds logically on this previous research, and serves as a backdrop to explore this unified test and analysis across the adult lifespan (i.e., three age groups). Steady-state response amplitudes will be assessed over a wide range of stimulus repetition rates embracing the traditionally measured transient AEPs. Of particular interest are ASSRs dominated by activity from the auditory cortices (< 20 Hz) and the age- dependent distribution and spectral patterns at three midline, two lateral and two temporal electrodes. In addition, steady-state recording parameters and subject-related characteristics will be examined to determine if they behave similarly to their transient-AEP counterparts.