June 28, 2012
Hearing loss can also mean increased sensitivity to vibrations
People with a particular, hereditary hearing loss called DFNA2 are more sensitive to low frequency vibrations.
People who have the hereditary hearing loss with the clinical name DFNA2 are at the same time more sensitive to vibrations. These are the findings of a German research team who believe that DFNA2 patients are extremely sensitive to vibrations.
A mutation affecting the function of the tiny hair cells in the inner ear is the cause of DFNA2 hearing loss. It is the tiny hair cells in the inner ear which convert sound waves. These vibrations trigger an influx of positively charged potassium ions into the hair cells. The potassium ions flow through a channel in the cell membrane and the exit from the hair cells. The DFNA2 mutation damages this potassium channel, what experts call the KCNQ4 protein molecule. The excess pressure leads to the demise of the sensory cells.
Perceive very slow vibrations
Patients with this type of hearing loss could perceive very slow vibrations that a healthy control group could not perceive. The reason is a change in the mechanoreceptors for normal touch sensation because of the mutation in the KCNQ4 channel.
“We found that KCNQ4 is not only present in the ear, but also in some sensory cells of the skin. This gave us the idea that the mutation might also affect the sense of touch. And this is exactly what we were able to show in our research,” said Thomas Jentsch from Leibnitz-Institut für Molekulare Pharmakologie (FMP) who led the study together with the Max Delbrück Center for Molecular Medicine Berlin-Buch (MDC).
The results were presented in the journal Nature Neuroscience.