Genetic variants in the peripheral auditory system significantly affect adult cochlear implant performance

•Cochlear implant (CI) outcomes are variable.•We hypothesize that the health of the neural component of the peripheral auditory system is an important factor in CI outcomes.•We show that adult CI users with deleterious mutations that affect the spiral ganglion perform significantly worse on speech recognition testing.•These results may guide pre-operative counseling for adult CI candidates.