A psychoacoustic ``NofM''-type speech coding strategy for cochlear implants (Q2502778)

Summary: We describe a new signal processing technique for cochlear implants using a psychoacoustic-masking model. The technique is based on the principle of a so-called ``NofM'' strategy. These strategies stimulate fewer channels (\(N\)) per cycle than active electrodes (NofM; \(N<M\)). In ``NofM'' strategies such as ACE or SPEAK, only the N channels with higher amplitudes are stimulated. The new strategy is based on the ACE strategy but uses a psychoacoustic-masking model in order to determine the essential components of any given audio signal. This new strategy was tested on device users in an acute study, with either 4 or 8 channels stimulated per cycle. For the first condition (4 channels), the mean improvement over the ACE strategy was 17\%. For the second condition (8 channels), no significant difference was found between the two strategies.