Predicting cochlear implant outcome from brain organisation in the deaf.

PURPOSE: Cochlear implantation is an effective technique for restoring hearing in the profoundly deaf. Although cochlear implants are a therapeutical success, huge performance variability in speech comprehension is observed after implantation. The reason for this remains incompletely understood after 20 years of clinical practice and basic research. Which patients are going to respond well and why is an unresolved question. The duration of auditory deprivation plays an important role, and currently is the main predictor of implantation success in children; basically, the earlier the better. However, among patients with identical duration of deafness, performance remains highly variable, suggesting there are other more fundamental factors that determine clinical outcome.
METHODS: To delineate the cognitive factors that could influence the clinical outcome of cochlear implantation, we correlated resting metabolism PET images acquired before implantation in congenitally deaf children with speech perception behavioural scores measured three years after implantation.
RESULTS: Using this paradigm, we showed distinct brain organisation patterns in the deaf brain, which predict good and bad speech perception outcome after cochlear implantation.
CONCLUSION: These data show that brain organisation assessed immediately before cochlear implantation can efficiently predict subsequent speech outcome.