Objective Detection of Auditory Steady-State Responses (ASSRs) Based on Mutual Information: Receiver Operating Characteristics and Performance Across Modulation Rates and Levels

Background: Auditory steady-state responses (ASSRs) are sustained potentials used to assess the physiological integrity of the auditory pathway and objectively estimate hearing thresholds. ASSRs are typically analyzed using statistical procedures to remove the subjective bias of human operators. Knowing when to terminate signal averaging in ASSR testing is critical for making efficient clinical decisions and obtaining high-quality data in empirical research. Here, we report on stimulus-specific (frequency, level) properties and operating ranges of a novel ASSR detection metric based on mutual information (MI). Methods: ASSRs were measured in n = 10 normal-hearing listeners exposed to various stimuli varying in modulation rate (40, 80 Hz) and level (80-20 dB SPL). Results: MI-based classifiers applied to ASSR recordings showed that the accuracy of ASSR detection ranged from ~75 to 99% and was better for 40 compared to 80 Hz responses and for higher compared to lower stimulus levels. Receiver operating characteristics (ROCs) were used to establish normative ranges for MI for reliable ASSR detection across levels and rates (MI = 0.9-1.6). Relative to current statistics for ASSR identification (F-test), MI was a more efficient metric for determining the stopping criterion for signal averaging. Conclusions: Our results confirm that MI can be applied across a broad range of ASSR stimuli and might offer improvements to conventional objective techniques for ASSR detection.