Graeme Clark Collection

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http://hdl.handle.net/11343/375

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Start date: 2000 × End date: 2009 × Author: O'Leary, Stephen × Type: Journal Item ×

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    Meningitis after cochlear implantation: the risk is low, and preventive measures can reduce this further
    Wei, Benjamin P. C. ; Clark, Graeme M. ; O'Leary, Stephen J. ; Shepherd, Robert K. ; Robins-Browne, Roy M. ( 2007)
    Since the 1980s, more than 80 000 people have received cochlear implants worldwide. These implants are designed to enable people who are severely or profoundly deaf to experience sound and speech. Since 1990, implantation has become standard treatment for people who cannot communicate effectively despite well fitted hearing aids. Children who are deaf when they are born can perceive sound and learn to speak if they receive cochlear implants at a young age (ideally under 18 months). The use of cochlear implants has been thought to be safe. But since 2002 the number of patients with meningitis related to cochlear implantation has increased worldwide. Mortality and neurological complications after meningitis are high. We need to investigate the reasons for this and look at measures to reduce them.
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    Histopathology of the binaural cochlear implant subject [Abstract]
    Yukawa, K. ; O'Leary, S. J. ; Clark, Graeme M. ( 2001)
    Binaural hearing improves speech reception in noise, and is necessary for sound localisation. Normal hearing subjects use both interaural time, and intensity, differences to localise sound. This study investigates why sound localisation in bilateral cochlear implantees is insensitive to interaural time differences (Hoesel 1993). We looked for evidence of neural degeneration in the auditory brainstem involved in binaural sound localisation, since this may have degraded the neural circuitry required to accurately code interaural time delays. Method: The brainstem of a bilateral cochlear implantee was prepared for light microscopy by embedding it in paraffin, sectioning at 10 mm and staining sections with thionine or Luxol fast blue (LFB). The histological sections were digitised with NIH Image and 3-dimensional reconstructions made of the cochlear nucleus (CN) and superior olivary complex (SOC) with AnalysePC. Within the CN and the SOC, cell number and size were estimated by the physical dissector technique following thionine staining, and myelination of the nerve fibres was estimated using the optical density method following LFB staining. Results: A reduction in cell size (from thionine staining) and myelination (from LFB staining) was seen in both the CN and the SOC. Conclusions: These finding are consistent with neural degeneration within the auditory pathways. This may have lead to a degradation of the neural circuitry required to accurately detect interaural time delays.