Clinical Trial Details
— Status: Withdrawn
Administrative data
| NCT number |
NCT02815124 |
| Other study ID # |
160461 |
| Secondary ID |
R01DC014462 |
| Status |
Withdrawn |
| Phase |
N/A
|
| First received |
|
| Last updated |
|
| Start date |
December 2021 |
| Est. completion date |
December 31, 2021 |
Study information
| Verified date |
January 2022 |
| Source |
Vanderbilt University Medical Center |
| Contact |
n/a |
| Is FDA regulated |
No |
| Health authority |
|
| Study type |
Interventional
|
Clinical Trial Summary
Cochlear implants are surgically implanted devices which restore the ability to hear to the
hearing impaired. While remarkably successful, even in the best of performers restoration of
hearing to levels of normal listeners is unusual. Approximately 3 weeks after surgery,
cochlear implants are activated via mapping - a process in which each individual electrode
(FDA approved cochlear implants have between 12 and 22 electrodes) is turned on and the
stimulus level adjusted to a level that is comfortable and beneficial to the recipient. At
present, this standard of care mapping procedure is performed without knowledge of the
physical location between the cochlear implant electrodes and the neural interface. Our team
has developed a new method of mapping using post-operative CT scans and image processing to
specify the physical relationship between the cochlear implant electrodes and the neural
interface allowing customized mapping. Using this information, the investigators deactivate
sub-optimally positioned electrodes. The investigators term this "Image-guided Cochlear
Implant Programming" (IGCIP). In a prospective fashion, the investigators have implemented
IGCIP on cochlear implant recipients who have had at least 6 months of standard of care (SOC)
mapping. The purpose of this study is to perform a randomized controlled trial (RCT) on newly
activated cochlear implant recipients randomizing between IGCIP and SOC.
Description:
Over 320,000 individuals have received cochlear implants (CIs) to restore hearing to the
hearing impaired. Commercially available CIs have 12, 16, or 22 independent electrodes (the #
is dependent on the manufacturer of the CI) which cover the entire frequency spectrum of the
cochlea from 20,000 Hertz (Hz) at the base of to 200Hz at the apex. After implantation, an
audiologists individually adjusts stimulation levels of each electrode following which all
electrodes are turned on such that the whole frequency spectrum of speech can be appreciated.
This is known as "standard of care" (SOC) programming. While postoperative speech
understanding is significantly better than preoperative levels, even the best performers
complain that the fidelity of natural hearing is not reproduced. Additionally, a significant
minority achieves poor outcomes despite normally functioning equipment for reasons that are
unknown but likely relate to poor neural survival; however, this cannot be confirmed as
post-mortem histopathology is required to accurately document spiral ganglion cell count.
In recent years much attention has focused on the interface between the cochlear implant
electrodes and the auditory neurons they are stimulating. Technological improvements at
Vanderbilt in imaging processing have made it possible to determine the location of each
electrode array in relationship to the frequency spectrum of the cochlea.
Using this information, the investigators have developed a new method of CI programming which
they call image-guided cochlear implant programming, or IGCIP in which sub-optimally placed
electrodes are turned-off or deactivated. Sub-optimally placed electrodes are defined as ones
for which their neighboring electrodes are in closer proximity to the site of their neural
stimulation. By deactivating sub-optimally positioned electrodes, channel interaction is
reduced allowing a cleaner signal to be presented to the auditory nerve.
The investigators have implemented this strategy on 133 CIs of post-lingually deafened
(hearing loss after the ability to speak) adult CI users with median use of their CI's with
SOC programming of 1.3 years (range 0.3-15.5). When trialing IGCIP, mean word scores
increased from 48.8±23.7% to 53.3±22.8% correct, and mean sentence scores increased from
62.2±28.5% to 65.0±26.9% correct. Both of these finding were statistically significant.
Extracting out the pre-lingually (hearing loss before the ability to speak) deafened adults,
the investigators see that for word scores, 24 of the 133 (28%) had statistically significant
improvement 12 of the 133 (9%) had statistically significant decline, and the remaining 97
(73%) had equivocal results. Similarly, for the sentence scores, 36 of the 133 (27%) had
statistically significant improvement 24 of the 133 (18%) had statistically significant
decline, and the remaining 73 (55%) had equivocal results.
Perhaps the most important metric is which map patients select for long term use - SOC or
IGCIP. Ninety-six of the 133 (72.1%) participants elected to keep IGCIP for long term use
despite prior research that shows that there is a bias for CI recipients to favor their
original map over a new map. And, for the 28% for elected to keep their SOC map, the process
involves no risk - the deactivated electrodes are simply reactivated. Given these exciting
prospective findings, the investigators are now proposing a randomized controlled trial (RCT)
for newly activated adult CI recipients with both the CI user and testing audiologist blinded
as to program (SOC or IGCIP). The investigators hypothesize that CI recipients randomized to
IGCIP will have improved hearing performance as assessed by both word and sentence testing.
