In 12 (33.3%) patients the examination of both ears was normal for all the semicircular canals, in 12 patients the results from the affected ear were abnormal in at least 1 of the semicircular canals, in 11 (30.5%) patients the results were abnormal in at least 1 of the semicircular canals in both the affected and unaffected ears, and in 1 (2.9%) patient the results were abnormal only in the unaffected ear. The most frequent abnormal result was obtained from the posterior canal of the affected ear and from the coupled superior canal of the unaffected ear. The distribution of abnormal findings was dependent on the disease duration and hearing loss.
Objectives:
The aim of this study was to determine whether the dexamethasone-eluting electrode (DEXEL) has a protective anti-inflammatory effect in a normal hearing implanted cochlea, as well as its performance and safety.
Design:
Ten healthy and normal hearing cynomolgus macaques (Mf) were divided into two cohorts: DEXEL group (DG) (CONCERTO CI device containing a DEXEL) and conventional CI group (CG) (unmodified CONCERTO CI device). The electrode was inserted into the scala tympani via the round window with an angle of insertion of 270 degrees. Auditory, impedance, electrically evoked compound action potential (eCAP), and recovery of function measurements were recorded monthly until sacrifice at 6 months post-implantation. A histologic analysis was also performed.
Results:
At 6 months, measurement of auditory brainstem responses revealed a mean threshold shift, as well as a mean impedance value, lower in the DEXEL group. The minimum eCAP for the remaining active contacts in the DEXEL group was 68% of that in the conventional CI group. Also at 6 months, the eCAP amplitude produced by a stimulating current of 800 cu (eCAP800) was almost 2.5-fold higher in the DEXEL group than in the conventional CI group (1338.86 ± 637.87 μV versus 545.00 ± 137.37 μV; p = 0.049). Tissue reactions, in particular fibrosis and ossification, were more common in the conventional CI group.
Conclusions:
The CI electrode array equipped with a dexamethasone-eluting component tested in macaques evidence that delivery of dexamethasone to the inner ear may produce rapid and long-lasting improvement of hearing with fewer neural tissue reactions.
With application of minimally traumatic surgical techniques, it is possible to maintain high rates of hearing preservation after implantation and even after reimplantation. Partial impairment of auditory thresholds may occur during the first weeks after surgery, which remains stable. Considering the tonotopic distribution of the cochlea, we found a correlation between the histological lesions sites and the auditory findings, suggesting that a rupture of the basilar membrane may impact hearing levels. The macaque was observed to be a functionally and anatomically an excellent animal model for cochlear implantation.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.