There is a wide range in performance for cochlear implant (CI) users and there is some evidence to suggest that implant fitting can be modified to improve performance if electrodes that do not provide distinct pitch information are de-activated. However, improvements in performance may not be the same for users of all CI devices; in particular for those with Cochlear devices using n-of-m strategies (ACE or SPEAK).
The goal of this research was to determine for users of Cochlear devices (CP810 implants with system 5 or 6 sound processors) if speech perception could be improved when indiscriminable electrodes were de-activated and this was also compared to when the same number of discriminable electrodes were de-activated.
A cross-over study was conducted with thirteen adult CI users who received experimental maps with de-activated channels for a minimum of two months and these were compared to an optimised clinical programme.
The findings showed that there were no significant benefits of electrode de-activation on speech perception and that there was a significant deterioration in spectro-temporal ripple perception when electrodes were switched off. There were no significant differences between de-activation of discriminable or indiscriminable electrodes.
These findings suggest that electrode de-activation with n-of-m strategies may not be beneficial.