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ABR and DPOAE

Simultaneous Auditory Stimulation and Recording

Overview

TDT’s ABR and DPOAE acquisition system for small mammals is designed for rapid phenotyping, drug screening, and pre-clinical studies. From our 30 years of scientific and engineering experience, TDT has developed a turnkey solution for your auditory research. Our all-in-one system features the RZ6 hardware and BioSigRZ software for streamlined ABRs and DPOAEs.

The RZ6 is an embedded solution for data acquisition and sound production. Its operating system provides real-time control of simple and complex sounds, sound normalization intensities across all frequencies, and the incoming signal for immediate viewing and analysis. High quality analog inputs and outputs on the RZ6 combine a large dynamic range and excellent signal-to-noise for controlling speakers and microphones.

Combined with the BioSigRZ software, the RZ6 is a complete system for running your ABR and DPOAE experiments.

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Published research: ABR/DPOAE

The newest papers in ABR/DPOAE that used TDT systems.

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Clinical and Experimental Pediatrics · 2026

Maternal metformin protects developing auditory brainstem function after neonatal hypoxia-ischemia in a neonatal rat model

Sei Eun Kim, Joo Young Kweon, Yong Joo Ahn, Jun Hee Kim

Background: Neonatal hypoxia-ischemia (HI) disrupts brain development and can impair sensory circuit maturation. However, how HI vulnerability is modified within developing auditory pathways remains poorly defined. Purpose: Metformin is used during pregnancy in select cases and modulates cellular energy signaling. Here, we tested whether maternal metformin administration during gestation alters functional and cellular outcomes in offspring brain after neonatal HI. Methods: Pregnant rat dams received metformin in drinking water, and offspring rat pups underwent HI during early postnatal life. Auditory pathway function was assessed in vivo using auditory brainstem responses (ABRs), and cellular pathology within the medial nucleus of the trapezoid body (MNTB) was evaluated by immunohistochemistry across postinjury developmental time points. Results: HI significantly elevated click-evoked ABR thresholds and reduced wave II and III amplitudes, whereas maternal metformin exposure prevented the HI-induced click-threshold elevation and preserved wave II and III amplitudes without altering peripheral or central conduction times. Histologically, HI produced an age-dependent decline in MAP2-positive neuronal density in the MNTB, culminating in marked neuronal loss at later postnatal stages. Notably, maternal metformin partially rescued HI-associated reductions in MNTB neurons, with a parallel trend toward preservation of oligodendrocyte lineage cells. Conclusion: Together, these findings indicate that maternal metformin administration during pregnancy enhances metabolic signaling and mitigates HI-related auditory brainstem dysfunction and cellular pathology in offspring, supporting maternal metabolic modulation as a determinant of neonatal sensory brain injury outcomes.

Read the paper → (Maternal metformin protects developing auditory brainstem function after neonatal hypoxia-ischemia in a neonatal rat model, opens in a new tab)
Materials Today Bio · 2026

A viscosity-tunable microgel-in-sol phase for localized inner ear delivery of small hydrophilic drug

Sumin Kim, Jee Hyun Kang, Seong Su Won, … Mikyung Shin

Cisplatin-induced ototoxicity leads to irreversible hearing loss in approximately 50% of treated patients, largely due to the cochlea's exceptionally poor cisplatin clearance compared with other organs. Although sodium thiosulfate (STS), a hydrophilic small molecule, is an established otoprotectant, achieving therapeutically sufficient cochlear concentrations remains challenging because systemic administration is limited by the blood-labyrinth barrier. Here, we report a viscosity-tunable microgel-in-sol system based on hyaluronic acid (HA) that enables sustained, localized delivery of STS to the inner ear via intratympanic injection. The STS-loaded microgel was readily injectable through 31 G needles and provided a six-fold extension in drug release duration compared with free STS solution. However, direct microgel injection caused significant occlusion of the middle ear cavity due to swelling and poor clearance. To overcome this limitation, we developed a microgel-in-sol formulation composed of an HA solution and microgel at a 3:1 volumetric ratio. This formulation exhibited concentration-dependent, lubricant-like viscosity while maintaining effective drug delivery and preserving auditory function, as confirmed by in vivo auditory brainstem response (ABR) measurements. Overall, this microgel-in-sol strategy represents a biocompatible, minimally invasive approach for localized inner-ear drug delivery.

Read the paper → (A viscosity-tunable microgel-in-sol phase for localized inner ear delivery of small hydrophilic drug, opens in a new tab)
Journal of Biological Chemistry · 2026

Hearing loss associated with CDC42 in mice and humans (Takenouchi-Kosaki syndrome): CDC42 and RHOQ synergistically function in cochlear hair cells

Takehiko Ueyama, Akira Ganaha, Shunkou Kurasawa, … Hirofumi Sakaguchi

CDC42 is involved in multiple signaling pathways, including actin organization and polarity. We previously reported progressive sensorineural hearing loss (SNHL) in inner ear hair cell (HC)-specific Cdc42-knockout (Atoh1-Cre+/-;Cdc42flox/flox) mice. However, the phenotype was milder than expected, suggesting possible redundancy with other Rho-family GTPases. Thereafter, Takenouchi-Kosaki syndrome (TKS), caused by de novo CDC42 mutations and manifesting as SNHL, was reported, in which the p.Y64C mutation was speculated to be constitutively active. However, the relationship between CDC42 status and hearing phenotypes in TKS remains unclear. Using cell models, mouse models, and patient data, we propose that impaired and/or dysregulated cycling between GDP/inactive and GTP/active forms, through either loss-of-function or constitutive activation, can lead to SNHL. Furthermore, to test redundancy, we generated HC-specific Cdc42;RhoQ double-knockout (Atoh1-Cre+/-;Cdc42flox/flox;RhoQflox/flox) mice, which revealed synergistic roles of CDC42 and RHOQ in cochlear HCs. Supporting this synergy, MDCK cells with CDC42 and RHOQ double knockdown showed greater phospho-cofilin, a key regulator of actin turnover, elevation than single knockdowns.

Read the paper → (Hearing loss associated with CDC42 in mice and humans (Takenouchi-Kosaki syndrome): CDC42 and RHOQ synergistically function in cochlear hair cells, opens in a new tab)

An Easily Configured Auditory System

Simplified ABRs

ABRs could not be easier to setup and acquire. With the RZ6, the only cables are from the device to the speakers, from the animal to the Medusa4z amplifier and from the amplifier to the recording rig.

Simplified connections minimize the potential of mis-wiring, as well as signal loss from damaged cables. The amplifier makes electrode connection a breeze, and the onboard impedance measurement ensures proper signal connection.

For more information, please see the ABR User Guide and remember that TDT is always here to assist with system setup and debugging.

Improved Amplifier for ABRs

The Medusa4Z is an all-in-one amplifier designed to simplify connections to the RZ6 hardware and electrodes.

The Medusa4Z has a large input voltage with a nanoVolt resolution and can record signals from sub microVolt ABRs to milliVolt EMGs.

An Easily Configured Auditory System

Simplified DPOAEs

To record DPOAEs, the two analog outputs on the RZ6 are utilized to drive two speakers simultaneously. A microphone is then connected to an analog input to record the subject’s response.

In addition to DPOAEs, the analog inputs connected to the integrated microphone amplifier also provide the perfect solution for speaker calibration and Ultrasonic Vocalization studies.

For more information, please see the DPOAE User Guide and remember that TDT is always here to assist with system setup and debugging.

Streamlined Software

BioSigRZ for ABRs & DPOAEs

The BioSigRZ software was designed for the RZ6. With a maximum sample rate of 200 kHz, the software can handle most ABR or DPOAE projects.

BioSigRZ integrates stimulus design and control, speaker calibration, and ABR/DPOAE acquisition all into one user interface. With this simple interface, you can control all components of the stimulus, from intensity and frequency to interstimulus intervals.

Projects take minutes to setup, and once complete, the system is ready for use by anyone in the lab.

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Webinar

Introduction to ABRs

This presentation provides an overview of Auditory Brain Responses (ABRs) and demonstrates TDT’s turnkey ABR hardware and software.

TDT explains how our ABR system leads to easy and robust ABR recordings for high throughput hearing research. Learn best practices for acquiring ABRs and the key things to consider when using TDT’s ABR system.

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