Trial-by-trial auditory brainstem response detection.

The neural response of the brainstem to brief sounds, known as the auditory brainstem response (ABR), is widely employed in the laboratory and the clinic to diagnose hearing loss. Current ABR approaches are limited to analyzing the average ABR to hundreds of stimulus trials. Historically, trial-by-trial ABR analysis has not been possible owing to each trial's small signal-to-noise ratio. Here we overcome this limitation and show how to score individual ABR trials. We use the distribution of individual-trial ABR scores to define thresholds, which we call auditory brainstem detection (ABD) thresholds, and to assess suprathreshold hearing. Scores based on individual-trial amplitude and similarity produce lower ABD thresholds than scores based on individual-trial amplitude alone. Our method enables us to rank the suprathreshold hearing of individual subjects. Despite having normal ABR thresholds, some subjects appear to have suprathreshold hearing deficits.