Assessing hearing and hearing loss in mice with OpenSABR (Open-source System for Auditory Brainstem Response)

The auditory brainstem response (ABR) is a measure of the neurophysiological response to sound, widely used in clinical and research settings. Here, we describe OpenSABR ("Open-source System for ABR"), an open-source system for measuring the ABR that is more flexible and about fifty times cheaper than closed-source alternatives. The heart of our system is the commercially available Texas Instruments ADS1299 chip for multi-channel differential recording. We designed auxiliary hardware and software to record and visualize the ABR. To demonstrate high-quality recording, we measured the response in mice to free-field auditory clicks from the left and right. We show that OpenSABR yields data consistent with prior work, introduce new methods for analyzing ABR waveforms, benchmark these methods against existing tools, compare variability within and between individuals, and detect the decreased auditory sensitivity associated with conductive hearing loss. Unlike proprietary alternatives, our system is highly flexible and could be customized for recording other biosignals like electromyography (EMG), electrocardiography (ECG), and sensory or motor evoked potentials. The low cost of OpenSABR (about $400) could broaden access to biosignal recording in research and education. This system is intended for research purposes and is not evaluated or approved for clinical use in humans, but if validated its low cost could broaden access to diagnosis of hearing and balance disorders.