By Achim Schilling and Patrick Krauss: For Complete Post, Click Here…
Subjective tinnitus is a perceived sound in the absence of any objective sound source. This phantom perception has severe consequences, ranging from insomnia to depression or even suicide. Furthermore, tinnitus is assumed to accelerate cognitive decline. However, a recent study showed that in non-hispanic elderly people, tinnitus is associated with a better cognitive function compared to an age- matched control group.
This finding is counter-intuitive, as tinnitus is highly correlated with hearing loss, and hearing loss is highly correlated with cognitive decline. So how is it possible that a phantom sound causing unwanted and severe side effects is associated with decreased cognitive decline?
We argue that tinnitus is a side effect of a processing mechanism in the auditory system to compensate for reduced auditory input by exploiting a phenomenon called stochastic resonance. In particular, the auditory system uses internally generated neural noise from the somatosensory system to lift a sub-threshold auditory signal above the detection threshold. We could already show in computer simulations that this mechanism has the potential to significantly increase speech perception in hearing impaired people.