Preservation of rhythmic clocking in cochlear implant users: a study of isochronous versus anisochronous beat detection

The capacity for internal rhythmic clocking involves a relationship between perceived auditory input and subsequent cognitive processing by which isochronous auditory stimuli induce a temporal beat expectancy in a listener. Although rhythm perception has previously been examined in cochlear implant (CI) users through various tasks based primarily on rhythm pattern identification, such tasks may not have been sufficiently nuanced to detect defects in internal rhythmic clocking, which requires temporal integration on a scale of milliseconds. The present study investigated the preservation of such rhythmic clocking in CI participants through a task requiring detection of isochronicity in the final beat of a four-beat series presented at different tempos. Our results show that CI users performed comparably to normal hearing (NH) participants in all isochronous rhythm detection tasks but that professionally trained musicians (MUS) significantly outperformed both NH and CI participants. These results suggest that CI users have intact rhythm perception even on a temporally demanding task that requires tight preservation of timing differences between a series of auditory events. Also, these results suggest that musical training might improve rhythmic clocking in CI users beyond normal hearing levels, which may be useful in light of the deficits in spectral processing commonly observed in CI users.