Changes in the cerebral blood flow in postlingual cochlear implant users

Five postlingually deaf patients (age range 28-58 years) with multichannel cochlear implants were examined with single photon emission tomography (SPE CT) (triple-head rotating gamma camera). Changes in the regional cerebral b lood how (rCBF) after intravenous administration of technetium-99m ethyl cy steinate dimer (Tc-99m ECD) were assessed through a stimulation paradigm, c onsisting of. ij click stimuli (75 dB SPL) in the ear that was to be implan ted, 2 weeks before surgery; iii stimulation with the same click, one month after initial fitting. iii) stimulation with hearing sequential Spanish se ntences one month after initial fitting. The results showed a significant i ncrease in the rCBF in the primary left auditory area and in the right audi tory cortex, in conditions iii and iii). The rCBF also showed a significant asymmetrical increase in the frontal lobes when the patient was hearing se quential sentences (condition iiii) with asymmetrical distribution among pa tients. These results are discussed, principally the correlation between sp eech discrimination scores and the rCBF distribution in the frontal and tem poral lobes.