Relations between cochlear histopathology and hearing loss in experimental cochlear implantation
نویسندگان
چکیده
This study reviews the cochlear histology from four hearing preservation cochlear implantation experiments conducted on 73 guinea pigs from our institution, and relates histopathological findings to residual hearing. All guinea pigs had normal hearing prior to surgery and underwent cochlear implantation via a cochleostomy with a silastic-platinum dummy electrode. Pure tone auditory brainstem response (ABR) thresholds from 2 to 32 kHz were recorded prior to surgery, and at one and four weeks postoperatively. The cochleae were then fixed in paraformaldehyde, decalcified, paraffin embedded, and mid-modiolar sections were prepared. The treatment groups were as follows: 1) Systemic dexamethasone, 0.2 mg/kg administered 1 h before implantation, 2) Local dexamethasone, 2% applied topically to the round window for 30 min prior to cochlear implantation, 3) Local n-acetyl cysteine, 200 μg applied topically to the round window for 30 min prior to implantation, 4) inoculation to keyhole-limpet hemocyanin (KLH) prior to implantation, and 5) untreated controls. There was a significant correlation between the extent of the tissue reaction in the cochlea and the presence of foreign body giant cells (FBGCs), new bone formation and injury to the osseous spiral lamina (OSL). The extent of the tissue response, as a percentage of the area of the scala tympani, limited the best hearing that was observed four weeks after cochlear implantation. Poorer hearing at four weeks correlated with a more extensive tissue response, lower outer hair cell (OHC) counts and OSL injury in the basal turn. Progressive hearing loss was also correlated with the extent of tissue response. Hearing at 2 kHz, which corresponds to the region of the second cochlear turn, did not correspond with loco-regional inner hair cell (IHC), OHC or SGC counts. We conclude that cochlear injury is associated with poorer hearing early after implantation. The tissue response is related to indices of cochlear inflammation and injury. An extensive tissue response limits hearing at four weeks, and correlates with progressive hearing loss. These latter effects may be due to inflammation, but would also be consistent with interference of cochlear mechanics.
منابع مشابه
Effects of Parents’ Level of Education and Economic Status on the Age at Cochlear Implantation in Children
Introduction: Cochlear implantation can facilitate the development of communication skills in children with profound hearing loss. The objectives of our study were to determine the average ages at suspicion and diagnosis of hearing loss, amplification, intervention, and performing the cochlear implantation and to investigate the effects of the parents’ level of education and economic circumsta...
متن کاملThe effect of cochlear implantation on the improvement of hearing performance in children suffering from profound hereditary and Non-hereditary hearing loss
Introduction: Hearing is one of the dominant senses of humans. In fact, human beings learn the language which is spoken in their environment and, then, develop the capability to speak. Cochlear implantation is introduced worldwide as a method for the treatment of the severe-to-profound sensory-neural hearing loss. Therefore, the present study aims to investigate the effect of cochlear implantat...
متن کاملCornelia De Lange Syndrome and Cochlear Implantation
Introduction: Literature regarding the different degrees of hearing loss in patients with Cornelia de Lange syndrome (CDLS) reports that half of the affected patients exhibit severe to profound sensorineural hearing loss. We present the first pre-school child with CDLS who underwent cochlear implantation for congenital profound sensorineural hearing loss. Case Report: A 3-year-old boy with CD...
متن کاملComparison of the executive functions of elderly people with cochlear implantation and the elderly with hearing aids
Background : Hearing impairment affects all aspects of a personchr('39')s life, especially auditory perception, while the use of cochlear implantation or hearing aids has a positive effect on auditory function. The aim of this study was to compare the improvement of executive dysfunction in elderly people who are performing cochlear implantation with people who use hearing aids. Methods: The pr...
متن کاملInvestigating the Effect of Cochlear Size in Insertion of Electrode Depth in Patients with Cochlear Implantation evaluated by CT-Scan
Background Cochlear implant surgery is an invasive procedure for patients with bilateral Sensorineural hearing loss and may cause some risks such as cochlear damage. We aimed to evaluate the effectiveness of cochlear measures obtained by computed tomography (CT) scan in predicting depth of cochlear implant insertion. Materials and Methods This study was conducted in a retrospective and cross-se...
متن کاملDiagnostic value of CT and MRI of Temporal Bone in Cochlear Implantation Candidates
Background Cochlear implantation is an approved treatment which can be used to treat severe to profound hearing loss. Imaging before cochlear implant surgery is very important in decision making and assessing the temporal bone anatomy for surgery. We aimed to assess the diagnostic value of high resolution CT scan (HRCT), and MRI of temporal bone in candidate pati...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- Hearing Research
دوره 298 شماره
صفحات -
تاریخ انتشار 2013