Biomedical subjects
Publications and source records attributed to Z Vanat.
We present a case of bilateral absence of the eighth cranial nerve in the internal auditory meatus (IAM). This caused total failure of responses after cochlear implantation in a six-year-old patient with congenital deafness. Pre-operative magnetic resonance (MR) imaging is important to show not only the anatomy of the middle and inner ears but also the structures in the IAM.
We present our results with an 18-month follow-up for 15 adult patients treated with the Ineraid (formerly Symbion) four-channel intracochlear implant. All were postlingually deaf with profound or total hearing loss. Performance was tested in lipreading, implant only, and combined lipreading and implant modes using Boothroyd word lists, Bamford-Kowal-Bench (BKB) sentences, and Connected Discourse Tracking. Assessments were made after 10 hours of training and again at 9 and 18 months postimplantation. Mean scores at 18 months in the implant only mode were for Boothroyd word lists 39%, for BKB sentences 47%, and for connected discourse tracking 31 words per minute. In the combined implant and lipreading mode the mean scores were for Boothroyd word lists 85%, for BKB sentences 96%, and for connected discourse tracking 75 words per minute. A profile of implant performance against time shows that after 10 hours' training, 12 of the 15 subjects had some speech discrimination in the implant only mode for all three tests. When using their implant combined with lipreading, all 15 subjects improved their speech discrimination scores over those obtained with lipreading alone after 10 hours' training. By 9 months, all subjects had some speech discrimination in the implant only mode on all three tests. Between 9 and 18 months there was a slight trend toward improvement in implant performance, both when the implant was used alone and when it was combined with lipreading.
Managing a patient with acquired profound deafness with a cochlear implant involves a lifetime commitment to rehabilitation and also to maintaining the device in a functioning condition. This paper describes the Cambridge experience of maintaining the Ineraid cochlear implant in a series of 25 patients over a 4 year period. On average, maintenance (repair of replacement) of components was required every 2.3 months of implant use, although some minor variations were noted between patients, and between component type. This rate of failure is sufficient to cause an Implant Centre to consider provision for repairs and holding of spare stock. It should be remembered that each breakdown returns the patient to a deafened state, albeit temporarily, but this can cause significant distress.