Hidden Hearing Loss

The goal of this observational study is to investigate whether speech-in-noise perception deficits in older adults aged 60 years or older with objectively normal hearing thresholds are due to impaired ability of processing temporal cues in speech signals. The study further aims to examine whether cognitive and cortical mechanisms provide compensatory support for speech perception in challenging listening environments.

The goal of this clinical trial is to determine the efficacy of Clemastine Fumarate in the presence of engineered sound to treat age-related central auditory processing disorder (CAPD). This disorder impacts 800M patients worldwide, including \~1/3 people over 40 years of age and \~1/2 people over 65, resulting in an inability to hear in noisy environments. The primary hypothesis this study aims to test is: engineered sound, driving localized neural circuit activity, will enable Clemastine Fumarate to mature Oligodendrocyte cells and thus remyelinate these activated neural circuits. This Localized Oligodendrocyte Optimization Therapy (LOOT) was highly effective in preclinical animal studies so this clinical trial aims to answer if this therapy will translate to humans. The study is an adaptive design intended to compare the efficacy of the drug in the presence or absence of the engineered sound for improving hearing in noise ability. Trial participants will be tested for hearing thresholds and ability to isolate a sound signal from background noise. If they meet the inclusion criteria, they will be enrolled into one of the four arms of the study and undergo the proposed one-month treatment (drug and sound or respective placebos). After the treatment period, trial participants will be tested again for hearing thresholds and their ability to isolate s sound source of interest from background noise. The hypothesis to be tested in this clinical trial is that the one-month treatment will significantly improve the participant's ability to isolate a sound source of interest from background noise. The design has four arms, drug+sound, placebo+sound, drug+white noise, and placebo+white noise. Based on our preclinical data, control arms are all expected to show identical results, thus our adaptive design includes interim analyses to allow for dropping of two of the three placebo arms should the preclinical results be replicated as anticipated. We will also monitor each participant's general health during the duration of the clinical trial, which will be done by performing a number of blood tests, an EKG and a general physical before and after the one-month treatment period. We expect no significant changes since participants will take the drug for the one-month period at dosages already demonstrated safe in several Phase II studies of multiple sclerosis. Similarly, the engineered sound will be listened to for one hour per day during this month at sound intensities well below threshold that might cause noise-induced hearing damage.

It is known that the underlying problem in Hidden Hearing Loss (HHL) is cochlear synaptopathy (CS) and that low-spontaneous-rate auditory nerve fibers play an important role in this pathology. Therefore, it is suggested that low-spontaneous-rate auditory nerve fibers are damaged in HHL. Consequently, LS CE-Chirp-evoked ABR and HINT, which assesses CS by presenting stimuli of varying intensities and characteristics to provide information about auditory nerve fibers, will be used to evaluate participants both objectively and subjectively. Aim of the study: The main aim of this study is to investigate the relationship between the amplitude and latency values obtained with LS CE-Chirp-stimulated ABR and the critical Signal-to-Noise Ratio (SNR) obtained from the Hearing in Noise Test (HINT) in individuals suspected of having HHL. Hypotheses H0: In individuals suspected of having HHL, there is no relationship between the amplitude values of waves I, III, and V obtained with LS CE-Chirp ABR at 80, 90, and 100 dBnHL and the I/V amplitude ratio and the critical SNR obtained from HINT. H1: In individuals suspected of having HHL, there is a relationship between the amplitude values of waves I, III, and V obtained with LS CE-Chirp ABR at 80, 90, and 100 dBnHL and the I/V amplitude ratio, and the critical SNR obtained from HINT. Expected Results: The study will reveal how LS CE-Chirp stimulation affects ABR results in individuals suspected of having HHL, and the relationship between these results and HINT results will be examined. In this way, HHL will be evaluated both objectively (LS CE-Chirp ABR) and subjectively (HINT). Based on the findings, scientific outputs such as publications or projects are targeted. Importance: HHL has recently attracted increasing attention as a condition that significantly affects daily life. In today's world, where noise and noisy environments are prevalent, disadvantages arise in many aspects, particularly in communication. Therefore, the findings obtained in this study may contribute to a better understanding of HHL.

The goal of this interventional clinical study is to investigate the use of mild therapeutic hypothermia devices for preservation of sensory structures in the cochlea after noise exposure. The main aims of the study are: 1. To test the safety and best duration for use for a new hypothermia device. 2. To determine if the hypothermia device helps decrease noise-induced hearing loss in a group of firefighters. Participants will wear the mild therapeutic hypothermia therapy devices immediately after a fire service shift serially over a year. Researchers will compare results from those receiving the therapy to those from a control group (individuals receiving no therapy and a sham therapy).