PET-CT observations of cortical activity in pre-lingually deaf adolescent and adult patients with cochlear implantation.

Conclusions: The present study yielded useful information concerning pre-lingually deaf adolescents and adults who try or manage to understand languages. PET-CT can provide insights into brain plasticity and elucidate which mode of communication is the most effective for education of such patients.

Objectives: To study the cortical activity in pre-lingually deaf adolescent and adult cochlear implants (CI) users who have been trained in auditory-verbal/oral communication since childhood.

Methods: Using positron emission tomography (PET) and 18F-fluorodeoxyglucose (FDG), brain activities in six pre-lingually and two post-lingually deaf CI users (mean age at CI surgery = , 20.3 years; three males, five females) were compared with those of 10 normal age-matched controls (mean age = 27.1 years). Regional cerebral blood flow changes were measured during an acoustic presentation of a story.

Results: In compliant CI users, the number of hypermetabolic auditory-related areas was greater in those who had a CI in their 20s than in those who did so in their adolescence. In poor and non-compliant users, hypermetabolism was not seen in the auditory association area, but in the primary auditory areas (BA41) and the Broca's area (BA45). In post-lingually deaf CI users, no increase in the number of hypermetabolic areas was found in auditory-related regions.