Seminars in Hearing Research at Purdue

Toward Personalized Vagus Nerve Stimulation for Tinnitus: A Physiology Guided Multimodal Approach

Tinnitus affects 10-15% of the population and can substantially disrupt sleep, mental health, and quality of life. Current treatments often provide inconsistent or modest relief because both tinnitus and nervous system responses differ between individuals. Recently, paired auditory and electrical trigeminal nerve stimulation has received FDA approval, yet this therapy remains inconsistent (up to 25% do not show improvement). Noninvasive transcutaneous auricular vagus nerve stimulation (taVNS) has shown similar, less-than-optimal results as trigeminal stimulation, but has the added benefit of sympathetic stress reduction. A key barrier to progress with the taVNS technique is an inability to induce consistent and predictable physiologic changes with stimulation, as there is an absence of personalized frameworks that can tune stimulation parameters to an individual’s unique physiological state, perceptions, and comfort. We developed a research platform to personalize taVNS by combining ear based stimulation with real-time measures of brain and body responses. The system synchronizes brain activity and oxygenation, pupil size, heart rate variability, skin conductance, gastric activity, blood pressure and brief surveys of comfort and perception. Additionally, calibrated earphones standardize sound presentation, while a personalization algorithm identifies settings that balance physiological response and participant comfort. Our ongoing studies are comparing forms of stimulation: electrical based (traditional), and thermal and vibration based (novel). The goal of this work is to move away from a "one-size-fits-all" approach and toward personalized medicine. This work is a vital step toward creating a new generation of wearable devices that can provide predictable, life-changing relief for the tinnitus community.

The Effects of Earplugging on Blast-Induced Hearing Loss

Blast-induced hearing loss contributes to the high levels of hearing difficulties reported among military personnel. While ear plugs are provided to military personnel for protection, hearing damage still occurs. Blast exposure is a common source of auditory trauma during military operations and can damage both peripheral and central auditory systems in a single exposure, even without tympanic rupture. Previous work in our lab has characterized blast induced damage to peripheral and central auditory pathways at the 14 and 28-day timepoints post-blast, showing loss of OHC integrity as measured by DPOAE, reduction of click ABR amplitudes, and temporal modulation processing impairments. In this project, we look at electrophysiological measures of blast-induced hearing loss shortly after exposure and over a 28-day recovery period and we show the effects of earplugging on protecting the central auditory pathway. Preliminary results show earplugging protects ABR thresholds and measures of cochlear function but fails to protect central auditory systems as measured by envelope following responses (EFRs). Our working hypothesis is that earplugging protects peripheral systems from damage but fails to protect more complex temporal encoding because earplugs protect the cochlea but do protect from blast-induced traumatic brain injury. This work is a crucial step in better understanding blast-induced hearing loss and the role conventional hearing protection plays in protecting from it.

Not Just Noise:  Hormonal Variability in Auditory Processing

Sex differences are becoming an increasingly important variable in hearing research and are often treated as a simple comparison between males and females or as another source of variability in the data. Sex differences are not binary or static, and biological factors, such as endogenous hormones, that vary within an individual may influence auditory function. Estrogen is suggested to mediate sex-related differences in auditory processing. However, we do not yet understand how estrogen may mediate sex-related differences in temporal processing. We hypothesized that temporal processing would vary across low-estrogen (LE) and high-estrogen (HE) phases of the female menstrual cycle, with greater differences compared to males emerging during the HE phase. Premenopausal healthy females and age-matched males participated in behavioral temporal processing measures using gap-detection thresholds. Female participants were tested across LE and HE phases, with males included as a comparison group. Overall, temporal processing varied by biological group and stimulus type, with poorer performance observed during the HE phase and greater difficulty for speech-shaped noise than broadband noise. These preliminary findings suggest that hormones may provide important information about why auditory performance differs between and within individuals over time. This may also be clinically relevant as temporal processing is particularly important in complex listening environments and is not always captured by standard measures of hearing sensitivity. Therefore, considering hormonal variability may provide a more sensitive approach for understanding individual differences in hearing and, ultimately, how we interpret both behavioral and clinical auditory measures.

The Marine Biological Laboratory Summer School Experience: Exploring Hearing and Balance from Cells to Systems

In summer 2026, I participated in the intensive three-week Biology of Hearing and Balance course at the Marine Biological Laboratory in Woods Hole. The course combined lectures with extensive hands-on laboratory training spanning auditory and vestibular science, from inner-ear development and hair-cell function to central neural coding, hearing loss, and cochlear prostheses. Experiments included chick utricle and neonatal mouse cochlea dissections, tissue culture and immunostaining, inner-ear paint fills, confocal imaging and image analysis, scanning and transmission electron microscopy, and electrophysiological recordings from hair cells and brain slices. We also explored zebrafish lateral-line function, vestibular reflexes, ABR and DPOAE measurements, and in-vivo recordings from the auditory nerve, inferior colliculus, and auditory cortex. I completed two mini-projects examining zebrafish lateral-line afferent responses and modulation coding across the gerbil auditory pathway. In this talk, I will share highlights from these experiments, including some of the fascinating images and recordings we collected, and reflect on this immersive scientific experience.