New Criteria of Indication and Selection of Patients to Cochlear Implant

Numerous changes continue to occur in cochlear implant candidacy. In general, these have been accompanied by concomitant and satisfactory changes in surgical techniques. Together, this has advanced the utility and safety of cochlear implantation. Most devices are now approved for use in patients with severe to profound unilateral hearing loss rather then the prior requirement of a bilateral profound loss. Furthermore, studies have begun utilizing short electrode arrays for shallow insertion in patients with considerable low-frequency residual hearing. This technique will allow the recipient to continue to use acoustically amplified hearing for the low frequencies simultaneously with a cochlear implant for the high frequencies. The advances in design of, and indications for, cochlear implants have been matched by improvements in surgical techniques and decrease in complications. The resulting improvements in safety and efficacy have further encouraged the use of these devices. This paper will review the new concepts in the candidacy of cochlear implant. Medline data base was used to search articles dealing with the following topics: cochlear implant in younger children, cochlear implant and hearing preservation, cochlear implant for unilateral deafness and tinnitus, genetic hearing loss and cochlear implant, bilateral cochlear implant, neuropathy and cochlear implant and neural plasticity, and the selection of patients for cochlear implant

Models and analysis of vocal emissions for biomedical applications

This book of Proceedings collects the papers presented at the 3rd International Workshop on Models and Analysis of Vocal Emissions for Biomedical Applications, MAVEBA 2003, held 10-12 December 2003, Firenze, Italy. The workshop is organised every two years, and aims to stimulate contacts between specialists active in research and industrial developments, in the area of voice analysis for biomedical applications. The scope of the Workshop includes all aspects of voice modelling and analysis, ranging from fundamental research to all kinds of biomedical applications and related established and advanced technologies

Multiple perspectives on the association between cognition and speech-in-noise perception performance

This thesis investigated the role of cognition and hearing sensitivity in Speech-in-Noise (SiN) perception across different listener groups and SiN listening conditions. A typical approach to investigating the contribution of cognition is correlating cognitive ability to SiN intelligibility in populations controlled for or varied in age and/or hearing sensitivity. However, using this approach to advance our understanding of the contribution of cognition, and its potential interaction with age and hearing loss, for SiN perception has been limited by a combination of: A lack of systematicity in selection of SiN perception tests and a lack of theoretical rigor in selection of cognitive tests, a lack of comparability across studies due to differences in both cognitive test and SiN perception test selections, and in differences in age or hearing sensitivity ranges among tested populations, and the limitations of using a correlation study approach. Therefore, the main focus of the thesis will be to generate evidence to overcome these limitations in three purpose-designed investigations, discussed in chapters two, three and four respectively. In chapter two I report a systematic review and meta-analysis which took a systematic and theory driven approach to comprehensively and quantitatively assess published evidence for the role of cognition in SiN perception. The results of this chapter suggest a general association of r~.3 between cognitive performance and SiN perception, although some variability in association appeared to exist depending on cognitive domain and SiN target or masker assessed. In chapter three I present a study which used a theory-driven and systematic approach to investigate the contribution of cognition and listener characteristics (namely age and hearing sensitivity differences across younger and older listener groups) for SiN perception in different SiN conditions, using an association study design. The study revealed that the Central Executive contributed to SiN perception performance in older, but not younger listeners, regardless of SiN condition. Phonological Loop processing was important for both listener groups, but with a different role depending on age group and masker type. Episodic Buffer ability only contributed to SiN performance for older listeners, and was modulated by hearing sensitivity and background masker. In chapter four, building on the association study findings, I report a dual-task study that manipulated the availability of specific cognitive abilities for SiN perception for younger adult listeners. Here I provided further evidence to show Phonological Loop ability is more important than Central Executive ability and Episodic Buffer ability for SiN perception for this listener group, using a carefully controlled experimental design. In summary, the evidence from this thesis indicates that the role of different cognitive abilities for SiN perception can differ depending on age, hearing sensitivity and listening condition. Additionally, using a systematic approach and combining multiple methodological techniques has been informative in investigating these roles to a greater extent than has previously been achieved in the literature

Investigating the build-up of precedence effect using reflection masking

The auditory processing level involved in the build‐up of precedence [Freyman et al., J. Acoust. Soc. Am. 90, 874–884 (1991)] has been investigated here by employing reflection masked threshold (RMT) techniques. Given that RMT techniques are generally assumed to address lower levels of the auditory signal processing, such an approach represents a bottom‐up approach to the buildup of precedence. Three conditioner configurations measuring a possible buildup of reflection suppression were compared to the baseline RMT for four reflection delays ranging from 2.5–15 ms. No buildup of reflection suppression was observed for any of the conditioner configurations. Buildup of template (decrease in RMT for two of the conditioners), on the other hand, was found to be delay dependent. For five of six listeners, with reflection delay=2.5 and 15 ms, RMT decreased relative to the baseline. For 5‐ and 10‐ms delay, no change in threshold was observed. It is concluded that the low‐level auditory processing involved in RMT is not sufficient to realize a buildup of reflection suppression. This confirms suggestions that higher level processing is involved in PE buildup. The observed enhancement of reflection detection (RMT) may contribute to active suppression at higher processing levels