Graeme Clark Collection
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ItemA multiple-channel cochlear implant: evaluation using speech tracking( 1981)Two totally deaf patients who had received multiple-channel cochlear implants were tested using a speech "tracking" procedure in which they had to repeat verbatim passages of connected discourse. Their performance was assessed by calculating the tracking rate (words per minute) each session. Testing was carried out under two conditions - lipreading along and lipreading in conjunction with a multiple-channel cochlear implant and laboratory speech processor. Lipreading with the cochlear implant increased the tracking rates by a factor of four for one patient and by a factor of two for the other when compared with lipreading alone.
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ItemA multiple-channel cochlear implant: an evaluation using nonsense syllables( 1981)A study using nonsense syllables has shown that a multiple-channel cochlear implant with speech processor is effective in providing information about, voicing and manner and to a lesser extent place distinctions. These distinctions supplement lipreading cues. Furthermore, the average percentage improvements in overall identification scores for multiple-channel electrical stimulation and lipreading compared to lipreading alone were 71% for a laboratory-based speech processor and 122 % for a wearable unit.
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ItemMultiple-electrode cochlear implant for profound or total hearing loss: a review( 1981)Patients who have developed a profound or total hearing loss cannot receive help with a conventional hearing aid. A promising way of restoring usable hearing and helping them communicate, however, is by electrical stimulation of residual auditory nerve fibres. Recently, single electrodes have been used to globally stimulate the auditory nerve, and patients have been helped in distinguishing voiced from unvoiced speech sounds, and in hearing the rhythm and intonation of speech. However, it is generally agreed that, if more speech information is to be conveyed to the patient, a multiple electrode system which selectively stimulates small groups of auditory nerve fibres will be required.
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ItemTinnitus management in the profoundly and totally deaf( 1993)Tinnitus is a common symptom of many cochlear or auditory system pathologies. Since tinnitus is frequently associated with a sensorineural hearing loss, it is not surprising that a large proportion of profoundly and totally deaf patients describe tinnitus as a symptom. The clinical management of severe tinnitus in these patients is discussed with particular emphasis on the use of electrical stimulation. While cochlear implants appear to provide a measure of relief when being used, significant improvements in the management of severe tinnitus will only occur when we have a greater understanding of the underlying pathophysiology, diagnostic procedures that can accurately establish the site of tinnitus generation, and more objective clinical trial procedures that include the use of controls.
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ItemImplantation of the Melbourne/Cochlear multiple-electrode extracochlear prosthesis(Annals Publishing Co., 1989)The Melbourne/Cochlear multiple-electrode extracochlear implant is designed for deaf patients who are unsuited to multiple-electrode intracochlear implantation. The implant consists of a receiver-stimulator package connected via a lead wire assembly to six individual stimulating electrodes. There is a choice of two alternative surgical procedures, both of which are via a combined middle ear approach using anterior and posterior tympanotomies. Four active electrodes shaped into compressible platinum-iridium soft-balls are fed through the mastoid cavity and across the facial recess, and placed into cavities that are made over the cochlear turns that project to the medial wall of the middle ear. One hard-ball active electrode is placed into the round window niche. One hard-ball reference electrode is placed into the hypotympanum. An additional electrode wrapped around the lead wire assembly can be used as an alternative reference electrode. A specially designed insertion needle facilitates the placement and the fixation of the soft-ball electrodes.
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ItemProgressive ototoxicity of neomycin monitored using derived brainstem response audiometry( 1985)Progressive hearing loss following the systemic administration of neomycin was investigated using derived brainstem response audiometry. Cats were given three to five times the maximum recommended clinical dose of neomycin over a period of 10 days. Their hearing was monitored prior to and during the administration of the drug, and periodically following its completion. The results of this study showed that the induced hearing loss generally proceeded from high to low frequencies as an advancing lesion, with regions apical to the lesion functioning normally. Although considerable variability in response to the drug existed among animals, the evoked responses from both ears of each animal showed close bilateral symmetry during the deafening process. Futhermore, the present results highlight the long-term ongoing ototoxicity associated with neomycin, and the importance of monitoring high frequencies for initial signs of an aminoglycoside induced hearing loss.