The Mechanisms Underlying Tinnitus and Hyperacusis: A Comprehensive Overview

This article explains in details the role of OHC, IHC, increased gain, central gain, role of subcortical brain region, hidden hearing loss etc etc It is an interesting article:

Advances in the neurobiology of hearing disorders: Recent developments regarding the basis of tinnitus and hyperacusis

https://www.sciencedirect.com/science/article/pii/S0301008213000804

 

It is very insightful article, that emphasizes pivotal role of the stress. This agrees so much with my personal experience how I did develop my tinnitus. Simply speaking, I had some temporary tinnitus period/onset (for 2 months) in my early 20s when I have been studying for the exams and I was very stressed and mentally exhausted. Then tinnitus went away after I had a summer holidays and I got lot of sleep and relax. Then in my early 30s it got back when I had moderate acoustic trauma (blasting my headphones at full volume accidentally for 2sec) while being under lot of stress because of a new born baby, my dad being sick, running my own business. Unfortunately this 2nd time it did not went away.
I really start to believe that having more relaxed life and attitude would save me from tinnitus. But I had no luck in my life and it gave me lot of stressful moments and made me very nervous person.

 

Tinnitus and hyperacusis: central noise, gain and variance

Tinnitus is a phantom auditory sensation in the absence of external sounds, while hyperacusis is an atypical sensitivity to external sounds that leads them to be perceived as abnormally loud or even painful. Both conditions may reflect the brain’s overcompensation for reduced input from the ear. The present work differentiates between two compensation models: The additive central noise compensates for hearing loss and is likely to generate tinnitus, whereas the multiplicative central gain compensates for hidden hearing loss and is likely to generate hyperacusis. Importantly, both models predict increased variance in central representations of sounds, especially a nonlinear increase in variance by the central gain. The increased central variance limits the amount of central compensation and reduces temporal synchrony, which can explain the insufficient central gain reported in the literature. Future studies need to collect trial-by-trial firing variance data so that the present variance-based model can be falsified.