Objective Analysis of Early Auditory Responses Elicited by Gaps in Noise
Ȍzdamar, Khalid Alhussaini, Jorge Bohorquez, Fred Holt, Ȍzcan . 2015
Behavioral detection of gaps in noise (GIN) is commonly used to evaluate auditory temporal resolution. Late latency responses (LLRs) to such stimuli are studied as electrophysiological measures of temporal resolution. The current study was conducted to investigate the characteristics of auditory brainstem and middle latency responses (ABRs/MLRs) elicited by GIN. Additionally, Quasi Auditory Steady State Responses (QASSRs) were quantified to obtain an Objective Gap Detection Threshold (OGDT). Six young, normal hearing subjects were monaurally stimulated using silent gaps (durations 0ms-12ms) embedded in a white-noise signal. QASSRs were deconvolved using the CLAD (Continuous Loop Averaging Deconvolution) algorithm to obtain an estimate of the transient responses to individual gaps. Derived ABRs/MLRs were consistently characterized by three positive waves and three negative waves that diminished with decreasing gap duration. Early auditory evoked responses (ABR/MLR) to GINs were reliably recorded and computed OGDTs yielded results that are consistent with behavioral tests. This methodology may be applied to objectively diagnose patients with auditory disorders related with temporal resolution deficiencies.
