This is a little off the beaten path for me, but I thought any information on brain function is useful information. The following is from Science Daily.
A cochlear implant is an electronic device capable of restoring hearing in a profoundly deaf person by directly stimulating the nerve endings in the inner ear. This technology enables people who have become deaf to be able to communicate orally again, even by telephone, and children born deaf to learn to speak and to benefit from normal schooling. However, results can be extremely variable, with implants having only little benefit for some patients, without any means of predicting failure based only on purely clinical factors. Using data from brain imaging techniques that enable visualizing the brain’s activity, a neuroscientist at the University of Geneva (UNIGE) and a Parisian ENT surgeon have managed to decipher brain reorganization processes at work when people start to lose their hearing, and thus predict the success or failure of a cochlear implant among people who have become profoundly deaf in their adult life. The results of this research may be found in Nature Communications.

Up, red: right occipito-temporal coupling during deafness, indicating a poor cochlear implant prognosis. Below, blue: right occipito-tempora uncoupling after deafness, indicating a good cochlear implant outcome (adapted from Strelnikov et al. 2013).
Credit: © UNIGE – Institut Vernes, Paris