Tinnitus & hyperacusis

Outer Hair Cells, Inner Hair Cells, Synapses, and Hearing Loss.

Tinnitus and hyperacusis can have several causes: sudden or long-term loud sound exposure; age-related wear of the ear’s outer hair cells; certain medications that affect hearing (for example, some chemotherapy drugs and antibiotics); ear or middle ear conditions; head or neck injuries; jaw-joint (TMJ) problems; Ménière’s disease; acoustic neuromas; and inner ear circulation or metabolic issues. This page focuses on the inner ear noise-related pathway called synaptopathy or hidden hearing loss, where the tiny ribbon synapse connections between inner hair cells and the auditory nerve are stressed or damaged, but cannot be detected by pure tone audiometry, the standard hearing test. ACEMg was designed to target the oxidative stress and excitotoxicity noise injury process, which is the basis of our peer-reviewed research and the OTIS real-world study.

Making sense of tinnitus and hyperacusis starts by understanding the cochlea’s two key sensors — inner hair cells (IHCs), which convert sound into nerve signals, and outer hair cells (OHCs), which amplify and sharpen those signals. It distinguishes audiogram-detectable OHC hearing loss from “hidden hearing loss” (synaptopathy), in which the ribbon synapses linking IHCs to the auditory nerve are stressed or damaged despite normal thresholds. You will see an organ of Corti diagram, a summary of mechanisms such as excitotoxicity and central gain, and an explanation of why routine pure tone audiometry (PTA) tests miss synaptopathy. The page also outlines current investigations into hearing preservation, including hypotheses about ACEMg and the OTIS real-world study evaluating tinnitus and hyperacusis outcomes.

Outer hair cell hearing loss (HL)

Hearing loss is caused by dysfunction of outer hair cells (OHC), most often from noise exposure. OHC hearing loss can be detected by the audiogram – the subjective PTA test. PTA test results are used by audiologists and audiology technicians to program hearing aids, which selectively amplify sounds to compensate for the loss. A 2-year clinical study demonstrated that ACEMg preserved or improved OHC function for 75.3% of study participants who took ACEMg daily, with most results occurring within the first six months of use, and ACEMg holds a new patent for that. If you have been diagnosed with hearing loss using a PTA test, the odds are 3 in 4 that your ongoing use of ACEMg will help preserve the hearing you have, and PTA tests can be used to subjectively measure ACEMg's potential impact on OHC function.

Synaptopathy, or hidden hearing loss (HHL)

Recent basic research strongly indicates that noise exposure, even brief noise exposure, can often cause synapopathy, defined as impaired function of the nerves that connect inner ear cells with the auditory nerve, which causes noise-induced hidden hearing loss (NIHHL). Synaptopathy-induced NIHHL often manifests as tinnitus (T) and hyperacusis (H). The PTA does not detect NIHHL. Since ACEMg was introduced in 2017, some who routinely use ACEMg as Soundbites to protect their hearing have reported that it relieves tinnitus and hyperacusis symptoms. The OTIS study aims to assess the potential impact of ACEMg on NIHHL. If you have tinnitus or hyperacusis, consider enrolling in the OTIS study or purchasing test kits.

Tinnitus and hyperacusis are symptoms of synaptopathy.

Synaptopathy can happen fast

Tinnitus and hyperacusis are possible even with normal hearing. A single loud night out can disconnect 30–60% of synapses in the cochlea’s high-frequency zone without showing up in the audiogram because the standard audiogram only detects low-threshold nerve fibers that often survive, masking hidden losses. Studies show that even with normal thresholds, tinnitus patients can have up to 60% synapse loss, fewer nerve signals, and degraded timing accuracy, which makes sounds harder for the brain to decode.^[1]

The central nervous system responds to synaptic loss

When auditory nerve input is reduced, the brain responds by turning up its volume, called central gain, or boosts weak signals by adding neural noise, called stochastic resonance. Animal studies show damaged synapses sometimes regrow, but the rebuilt connections often transmit less precise timing cues. While these mechanisms help the brain detect faint sounds, central gain can manifest as hyperacusis, and stochastic resonance can become audible as tinnitus, noticed most when it is quiet.^{[1], [2]}

Inner hair cell excitotoxicity triggers synaptopathy

Synaptopathy is becoming an important target for hearing preservation, as research is revealing that excitotoxic nerve damage to inner hair cell (IHC)‑to‑auditory nerve (AN) ribbon synapses often happens long before outer hair cell (OHC) loss.

Excitotoxicity occurs when inner hair cells release too much glutamate during intense sound. The overstimulation floods the auditory nerve endings with calcium, allowing excess calcium into neurons, damaging mitochondria, destroying the synapse, and triggering central gain and stochastic resonance. Antioxidants can absorb harmful free radicals during the calcium surge, and magnesium helps keep cochlear vessels open so stressed synapses recover rather than fail.^[4]

ACEMg hypothesis for synaptopathy

The ACEMg formula preserves normal outer hair cell function and protects mitochondrial DNA by providing supplemental antioxidants A, C, and E, to neutralize singlet oxygen (free radicals), and maintains normal cochlear blood flow with Magnesium. In synaptopathy, inner hair cell (IHC) excitotoxicity generates free radicals during the calcium surge.

Thus, ACEMg may mitigate synaptopathy, preventing IHC excitotoxicity by scavenging reactive oxygen species generated during the calcium surge with antioxidants, preserving cochlear microcirculation and ionic balance with Magnesium, thereby reducing calcium overload at auditory nerve terminals, preserving ribbon synapses, and preventing downstream central gain and stochastic resonance, especially if administered during or shortly after intense sound exposure.

Proving the hypothesis

The OTIS study is a real‑world evidence study, also known as an epidemiological study, designed to evaluate the potential effectiveness of ACEMg for people with tinnitus and hyperacusis. Effectiveness is different from efficacy, which is the performance of a medical intervention under ideal and controlled circumstances. Typically, efficacy is determined in randomized controlled trials (RCTs) to determine whether a treatment can work in a best‑case scenario. Efficacy data does not necessarily translate to patient outcomes after a drug has been approved to be prescribed.

The OTIS study protocol uses a digits‑in‑noise test and surveys to collect data aimed at validating the hypothesis. The long range goal of this study is to allow anyone with hearing loss, tinnitus, or hyperacusis to assess how well ACEMg works for them. Data collection and analysis may continue for years.