New Research Suggests People with Tinnitus and HyperAcusis Should Avoid Quiet Environments
A great deal of anecdotal evidence suggests that people with tinnitus dislike quiet environments, and that they perceive quiet environments as increasing the subjective volume of their tinnitus.
However, up until this point, it is unclear whether the actual volume of tinnitus increases in a quiet environment, or if the absence of background masking sounds makes the tinnitus percept more salient (I personally believe it’s a combination of both).
New research lends credence to the former hypothesis: quiet environments may adjust the overall “sensitivity” of the auditory system, which can be conceptualized as the “gain” of the auditory system (in the same way that adjusting the “gain” on a guitar amplifier increases the volume of the outputted sound). Quiet environments appear to readjust the sensitivity of the auditory system and in doing so increase tinnitus volume and sensitivity to sound:
The present study uses a systems engineering approach to delineate the relationship between tinnitus and hyperacusis as a result of either hearing loss in the ear or an imbalanced state in the brain. Specifically examined is the input-output function, or loudness growth as a function of intensity in both normal and pathological conditions.
Tinnitus reduces the output dynamic range by raising the floor, while hyperacusis reduces the input dynamic range by lowering the ceiling or sound tolerance level.
Tinnitus does not necessarily steepen the loudness growth function but hyperacusis always does. An active loudness model that consists of an expansion stage following a compression stage can account for these key properties in tinnitus and hyperacusis loudness functions.
The active loudness model suggests that tinnitus is a result of increased central noise, while hyperacusis is due to increased nonlinear gain. The active loudness model also generates specific predictions on loudness growth in tinnitus, hyperacusis, hearing loss or any combinations of the three conditions. These predictions need to be verified by experimental data and have explicit implications for treatment of tinnitus and hyperacusis.
We’ll be posting more about this paper in the future, because it’s pretty exciting in that it presents a new model of understanding of tinnitus that links tinnitus, hyperacusis, and hearing loss. This theory proposes that:
- Hearing loss leads to both tinnitus (from increased central “brain noise”) and hyperacusis (from increasing auditory “gain”)
What Does This Mean in Practice?
- People with tinnitus and hyperacusis should have some light background noise at all times (be it music or masking sounds)
Now, the obvious qualification of this advice is that, one, it is still based on preliminary research, and two, you should never expose yourself to noise levels that could cause further hearing loss.
The take home: new research is actively helping us to determine how best to manage our tinnitus.