Why Do Some People Develop Tinnitus After Hearing Loss and Others Do Not? (part 2)
A lot of people are puzzled by the fact that even though two individuals may have the same level of hearing loss, some people will develop tinnitus and others will not. This suggests that people may have different underlying levels of vulnerability to developing tinnitus. We’ve posted about research in the past that confirms this, and a new paper has come out that details another possible explanation.
Here we for the first time compare behavioral and neurophysiological data from hearing impaired Mongolian gerbils with (T) and without (NT) a tinnitus percept that may elucidate why some specimen do develop subjective tinnitus after noise trauma while others do not. Although noise trauma induced a similar permanent hearing loss in all animals, tinnitus did develop only in about three quarters of these animals. NT animals showed higher overall cortical and auditory brainstem activity before noise trauma compared to T animals; that is, animals with low overall neuronal activity in the auditory system seem to be prone to develop tinnitus after noise trauma.
Here researchers appear to have uncovered one risk factor for developing tinnitus:
- Low overall neuronal activity in the auditory system
The abstract goes on to discuss more details:
We propose a model for tinnitus prevention that points to a global inhibitory mechanism in auditory cortex that may prevent tinnitus genesis in animals with high overall activity in the auditory system, whereas this mechanism seems not potent enough for tinnitus prevention in animals with low overall activity.
Thus, these researchers believe that in some brains, there is a stronger ability to inhibit activity in the auditory cortex (the region of the tinnitus percept) than in other brains.
Real progress is being made in our scientific understanding of tinnitus at a remarkable rate.