Hypothesis: The goals of this work were (a) to review the pre- and pos
tsurgical auditory thresholds in a consecutive sample of cochlear impl
ant recipients to determine the fate of residual hearing, and (b) to o
btain preliminary indication of the value of a multicenter longitudina
l study of residual hearing in implant patients. Background: Indicatio
ns for cochlear implantation have been expanded to include severely he
aring impaired (SHI) adults and may someday include SHI children. Impl
antation of individuals with more residual hearing is a concern owing
to the possible development of better devices that may make use of res
idual hearing within the lifetime of implanted children if not that of
adults. Preservation of residual hearing would be a desirable outcome
of implant surgery; however, conventional thought is that implantatio
n destroys any remaining hearing. This study was undertaken to assess
if and how often conservation of hearing occurred after implantation i
n a sample of multichannel implant recipients. Methods: Records of 50
profoundly hearing impaired consecutively implanted patients were exam
ined for pre- and postsurgical audiometric results. Standard audiometr
ic techniques were used for all testing procedures. Forty patients wer
e considered to have some hearing conserved based on a response obtain
ed at any one of the three speech frequencies prior to implantation. T
he most recent postimplantation audiometric results were used providin
g data from users with 1-41 months of use. Results: Twenty-one of 40 i
mplanted subjects were found to have responses in at least one of the
speech frequencies both pre- and postsurgery, with the majority of tho
se displaying responses at all three frequencies. In this preliminary
retrospective study, it did not appear that duration of cochlear impla
nt use, sender, level of preoperative hearing, or length of electrode
insertion were related to outcome. There were insufficient data to dra
w conclusions on individual devices. Conclusions: Conservation of hear
ing occurred in approximately half of the subjects reviewed. There is
no indication of what factors contributed to the preservation of heari
ng in those with postsurgical residual hearing or if that hearing is u
sable. The study does suggest that a larger multicenter longitudinal s
tudy would be of value to determine what factors may be related to con
served hearing in implanted patients.