253

The advantages of a deeply inserted, long cochlear implant electrode array have been demonstrated in several studies (Büchner et al 2004, Hochmair et al 2003, Böheim et al 2002). Benefits include extended  pitch domain, reduced channel interaction due to greater channel separation from base to apex, and better performance in noise with the apical electrode activated. Measures of benefit have been established by focusing on the contribution of the apical region to the performance of the patient in noisy and quiet environments. Without the apical electrode switched on, patients performed poorer in clinical testing. Adult benefits suggest that young and very young children will also benefit from the apical stimulation of the cochlea. Additional benefits for children may be related to the neural activation of central processes that is initiated by peripheral electrical stimulation. It has been demonstrated that stimulation of the auditory nerve through a cochlear implant within the critical time window of auditory development (within the first 4 years of age) initiates fastest functional maturation of the auditory cortex (Sharma et al, 2005). Stimulation of larger portions of the auditory nerve, as achieved in deep electrode insertions, would activate a larger area of the auditory cortex. Deep electrode insertions would therefore provide a better starting point for cortical development in prelingually deaf children.