Translational Research IFast and Accurate Diagnosis Using the Parallel Auditory Brainstem Response Objectives: The auditory brainstem response (ABR) is an essential tool in screening for and diagnosing infant hearing loss, and its results drive decisions regarding interventions and hearing habilitation with impacts extending far into a child’s future. Despite the traditional ABR exam’s usefulness, there is an identified need to develop faster, more informative exams. The parallel ABR (pABR) measures responses to all frequencies of interest in both ears all at once, rather than the traditional series of single-frequency measurements in one ear at a time, greatly speeding the exam. This talk will first provide an overview of the pABR, including how it works and advantages its construction offers over traditional approaches. We will then discuss results from a recent experiment in adults with hearing loss that tests the accuracy and speed of the pABR’s threshold determinations. Design: Seventy adults with widely varying sensorineural hearing loss configurations were recruited to participate in this study. We measured thresholds at octave frequencies in two ways: the behavioral audiogram, serving as the ground truth, and using the pABR with a custom-designed interactive user interface. Accuracy was determined through threshold correlation coefficients as well as absolute error in decibels. Acquisition time was assessed as the time from measurement start to determination of the tenth threshold. To determine the pABR’s speed advantages, a subset of participants were invited back and their thresholds estimated a third time, using a commercially available clinical system to serially measure ABR waveforms. Speedup was assessed in terms of the raw difference in acquisition time (minutes) and also as the ratio between measurement times made with the two ABR paradigms. Results: Thresholds estimated with pABR are highly correlated with the behavioral audiogram ground truth. The correlation was 0.90 (0.88–0.92 confidence interval) across all ears and frequencies. 79% of pABR thresholds were within one 10-dB step of the behavioral threshold, and 90% were within 14 dB. The pABR was faster in all ten subjects where traditional serial ABR was also recorded, with a mean recording time of 28 minutes to estimate ten pABR thresholds (500–8000 Hz in each ear) versus 70 minutes to estimate eight serial thresholds (500–4000 Hz in each ear), or a mean reduction of 42 minutes. The median speedup ratio was 2.5×. Conclusions: The pABR provides accurate threshold estimates with greatly reduced measurement time compared to traditional methods. Given these results and other advantages related to its design, the pABR holds promise as a clinical tool that can be deployed to commercial systems in the near future.
Ross Maddox earned his Ph.D. and M.S. in Biomedical Engineering from Boston University, and his B.S. in Sound Engineering from the University of Michigan. Following his Ph.D., he completed a postdoctoral appointment at the University of Washington Institute for Learning & Brain Sciences (I-LABS). Prior to joining the Kresge Hearing Research Institute at the University of Michigan as an associate professor, he was on the faculty of the Departments of Biomedical Engineering and Neuroscience at the University of Rochester. The Maddox lab uses electroencephalography and psychophysics together in human subjects to answer fundamental questions about how humans make sense of their noisy auditory world and how to improve diagnostic and assistive technologies.
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