PET study of auditory plasticity: Helping to address decision making for cochlear implantation of adults

The study of regional cerebral metabolism by positron emission tomography (PET) can be applied to the primary and associative auditory cortices, providing important information about normal hearing, hearing loss, and the neuroplasticity processes of the auditory system. We have reviewed the pertinent literature to provide the most significant facts that may help clinicians in the selection phase of a cochlear implant programme. PET-scan studies offer vital information concerning the time process for hearing restoration in cases of severe-profound hearing impairment. Additionally, we report a short case series of eight patients with long-lasting unilateral profound hearing loss combined with the contralateral ear having some functional hearing. These patients are quite difficult to counsel in the process of selection for cochlear implantation, as there is a lack of functional information on neural plasticity. PET-scan studies permit an evaluation of activation of both primary auditory cortices in patients with profound hearing impairment in one ear and contralateral functional hearing. This helps us to settle the question of a possible indication for a cochlear implant in the deaf ear.