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Francart T.,Catholic University of Leuven | Francart T.,The Bionics Institute | McDermott H.,The Bionics Institute | McDermott H.,University of Melbourne
PLoS ONE | Year: 2012

A significant fraction of newly implanted cochlear implant recipients use a hearing aid in their non-implanted ear. SCORE bimodal is a sound processing strategy developed for this configuration, aimed at normalising loudness perception and improving binaural loudness balance. Speech perception performance in quiet and noise and sound localisation ability of six bimodal listeners were measured with and without application of SCORE. Speech perception in quiet was measured either with only acoustic, only electric, or bimodal stimulation, at soft and normal conversational levels. For speech in quiet there was a significant improvement with application of SCORE. Speech perception in noise was measured for either steady-state noise, fluctuating noise, or a competing talker, at conversational levels with bimodal stimulation. For speech in noise there was no significant effect of application of SCORE. Modelling of interaural loudness differences in a long-term-average-speech-spectrum-weighted click train indicated that left-right discrimination of sound sources can improve with application of SCORE. As SCORE was found to leave speech perception unaffected or to improve it, it seems suitable for implementation in clinical devices. © 2012 Francart, McDermott. Source

Innes-Brown H.,The Bionics Institute | Marozeau J.,The Bionics Institute | Blamey P.,The Bionics Institute | Blamey P.,University of Melbourne
PLoS ONE | Year: 2011

Background: Enjoyment of music is an important part of life that may be degraded for people with hearing impairments, especially those using cochlear implants. The ability to follow separate lines of melody is an important factor in music appreciation. This ability relies on effective auditory streaming, which is much reduced in people with hearing impairment, contributing to difficulties in music appreciation. The aim of this study was to assess whether visual cues could reduce the subjective difficulty of segregating a melody from interleaved background notes in normally hearing listeners, those using hearing aids, and those using cochlear implants. Methodology/Principal Findings: Normally hearing listeners (N = 20), hearing aid users (N = 10), and cochlear implant users (N = 11) were asked to rate the difficulty of segregating a repeating four-note melody from random interleaved distracter notes. The pitch of the background notes was gradually increased or decreased throughout blocks, providing a range of difficulty from easy (with a large pitch separation between melody and distracter) to impossible (with the melody and distracter completely overlapping). Visual cues were provided on half the blocks, and difficulty ratings for blocks with and without visual cues were compared between groups. Visual cues reduced the subjective difficulty of extracting the melody from the distracter notes for normally hearing listeners and cochlear implant users, but not hearing aid users. Conclusion/Significance: Simple visual cues may improve the ability of cochlear implant users to segregate lines of music, thus potentially increasing their enjoyment of music. More research is needed to determine what type of acoustic cues to encode visually in order to optimise the benefits they may provide. © 2011 Innes-Brown et al. Source

Rickard N.A.,University of Canterbury | Rickard N.A.,The Bionics Institute | Smales C.J.,University of Canterbury | Rickard K.L.,University of Canterbury
International Journal of Pediatric Otorhinolaryngology | Year: 2013

Objective: One type of test commonly used to assess auditory processing disorders (APD) is the Frequency Pattern Test, in which triads of pure tones of two different frequencies are presented, and participants are required to accurately report the sequence of tones, typically using a verbal response. The test is widely used clinically, but in its current format, is an under-exploited means of addressing some candidate processes, such as temporal ordering and frequency discrimination, which might be affected in APD. Here we describe a computer-based version of an auditory pattern perception test, the BirdSong Game, which was designed to be an engaging research tool for use with school-aged children. Methods: In this study, 128 children aged 6-10 with normal peripheral hearing were tested. The BirdSong Game application was used to administer auditory sequential pattern tests, via a touch-screen presentation and response interface. A conditioning step was included prior to testing, in order to ensure that participants were able to adequately discriminate between the test tones, and reliably describe the difference using their own vocabulary. Responses were collected either verbally or manually, by having participants press cartoon images on the touch-screen in the appropriate sequence. The data was examined for age, gender and response mode differences. Results: Findings on the auditory tests indicated a significant maturational effect across the age range studied, with no difference between response modes or gender. Conclusions: The BirdSong Game is sensitive to maturational changes in auditory sequencing ability, and the computer-based design of the test has several advantages which make it a potentially useful clinical and research tool. © 2013 Elsevier Ireland Ltd. Source

Tovar-Lopez F.J.,University of Vic | Rosengarten G.,University of Vic | Nasabi M.,University of Vic | Sivan V.,University of Vic | And 6 more authors.
PLoS ONE | Year: 2013

This paper reports on an investigation of mass transport of blood cells at micro-scale stenosis where local strain-rate micro-gradients trigger platelet aggregation. Using a microfluidic flow focusing platform we investigate the blood flow streams that principally contribute to platelet aggregation under shear micro-gradient conditions. We demonstrate that relatively thin surface streams located at the channel wall are the primary contributor of platelets to the developing aggregate under shear gradient conditions. Furthermore we delineate a role for red blood cell hydrodynamic lift forces in driving enhanced advection of platelets to the stenosis wall and surface of developing aggregates. We show that this novel microfluidic platform can be effectively used to study the role of mass transport phenomena driving platelet recruitment and aggregate formation and believe that this approach will lead to a greater understanding of the mechanisms underlying shear-gradient dependent discoid platelet aggregation in the context of cardiovascular diseases such as acute coronary syndromes and ischemic stroke. © 2013 Tovar-Lopez et al. Source

Ganesan K.,University of Melbourne | Garrett D.J.,University of Melbourne | Ahnood A.,University of Melbourne | Shivdasani M.N.,The Bionics Institute | And 5 more authors.
Biomaterials | Year: 2014

The interface between medical implants and the human nervous system is rapidly becoming more and more complex. This rise in complexity is driving the need for increasing numbers of densely packed electrical feedthroughto carry signals to and from implanted devices. This is particularly crucial in the field of neural prosthesis where high resolution stimulating or recording arrays near peripheral nerves or in the brain could dramatically improve the performance of these devices. Here we describe a flexible strategy for implementing high density, high count arrays of hermetic electrical feedthroughs by forming conducting nitrogen doped nanocrystalline diamond channels within an insulating polycrystalline diamond substrate. A unique feature of these arrays is that the feedthroughs can themselves be used as stimulating electrodes for neural tissue. Our particular application is such a feedthrough, designed as a component of a retinal implant to restore vision to the blind. The hermeticity of the feedthroughs means that the array can also form part of an implantable capsule which can interface directly with internal electronic chips. The hermeticity of the array is demonstrated by helium leak tests and electrical and electrochemical characterisation of the feedthroughs is described. The nitrogen doped nanocrystalline diamond forming the electrical feedthroughs is shown to be non-cyctotoxic. New fabrication strategies, such as the one described here, combined with the exceptional biostability of diamond can be exploited to generate a range of biomedical implants that last for the lifetime of the user without fear of degradation. © 2013 Elsevier Ltd. Source

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