PubMed HealthSearch

Biomedical subjects

B C Pyman

Publications and source records attributed to B C Pyman.

23 records · Page 2Linked to original sources

Clinical trial of a multiple-channel cochlear prosthesis. An initial study in four patients with profound total hearing loss.

The clinical trial of a multiple-channel cochlear prosthesis was undertaken in four patients with postlingual deafness and profound total hearing loss. The results of open-set speech tests confirmed that, using electrical stimulation alone, one patient could have a meaningful conversation without resorting to lipreading (for example, this patient uses the prosthesis to converse with her husband on the telephone). The results of closed-set speech tests also suggested that a multiple-channel stimulator is more effective than a single-channel one in conveying speech information. The cochlear prosthesis was especially effective in all four patients when it was used in conjunction with lipreading, and speech-tracking tests showed that the patients could combine the information obtained from both electrical stimulation and lipreading.

Adult

Surgery for an improved multiple-channel cochlear implant.

An improved multiple-channel cochlear implant has been developed. The titanium container with enclosed electronics, the receiver coil, and the connector are embedded in medical-grade Silastic. The upper half of the implant has a diameter of 35 mm and a height of 4.5 mm, and the lower half a diameter of 23 mm and a height of 5 mm. The electrode array has also been designed to reduce the possibility of breakage due to repeated movements over many years. The surgery involves drilling a bed in the mastoid bone for the receiver-stimulator, and fixing the proximal electrode under the mastoid cortex. Gentle insertion of the electrode array through the round window and along the scala tympani is achieved with a specially designed microclaw .

Cochlear Implants

Banded intracochlear electrode array: evaluation of insertion trauma in human temporal bones.

A banded free-fit scala tympani array was inserted into the basal turn of nine human cochleas to evaluate the trauma produced by the procedure. These nine cochleas, together with five nonimplanted controls, were serially sectioned and examined microscopically for damage to the membranous labyrinth, in particular the spiral ligament, the basilar and Reissner's membranes, the stria vascularis, and the osseous spiral lamina. The severity and location of any trauma along the cochlear spiral were recorded. The results indicate that the insertion of the banded scala tympani array resulted in minimal mechanical damage, occurring primarily to a localized region of the spiral ligament. This would not result in significant neural degeneration, and therefore would not compromise the efficacy of the multichannel cochlear prosthesis.

Aged