The conversational skills of school-aged children with cochlear implants

Children with cochlear implants have been shown to have language skills on a par with children with severe hearing losses who have hearing aids. Earlier implants, bilateral implantation, and focused intervention programmes may result in some children with cochlear implants displaying similar language skills to their hearing peers. The development of pragmatic skills is central to communication competence and underpins the development of friendships. Although some studies of pragmatic skills in children with cochlear implants have been reported, most have used a contrived referential communication task rather than free conversation.

Method: This study investigated the conversational skills of 20 children with cochlear implants, aged between 9 and 12 years, in free conversation with their hearing peers. The pragmatic skills of these 20 deaf/hearing pairs or dyads were compared with the pragmatic skills of 20 hearing/hearing dyads. Pragmatic skills were analysed in terms of conversational balance, conversational turn types, and conversational maintenance. The impact of the participants’ level of speech intelligibility was also investigated.

Results: Children with cochlear implants tend to dominate conversations with their hearing peers. They initiated more topics, took longer turns, asked more questions, and tended to make more personal comments while their hearing friends tended to use more conversational devices and minimal answers. In contrast, pairs of matched hearing children were very balanced in all of these aspects of conversation. Speech intelligibility did not appear to impact consistently on the pragmatic skills of the children with cochlear implants but all children had a relatively high level of speech intelligibility.

Discussion: Rather than being characterized by frequent conversational breakdown as in older studies, children with cochlear implants had a strong grasp of basic conversational rules. They conversed in a similar way to some deaf adults who also have been shown to take control of the conversation. Findings are discussed for their implications for intervention and future research.

Separating the contributions of hearing, lexical knowledge and speech production to speech perception scores in children with hearing impairments.

Open-set word and sentence speech-perception test scores are commonly used as a measure of hearing abilities in children and adults using cochlear implants and/or hearing aids. These tests are usually presented auditorily with a verbal response. In the case of children, scores are typically lower and more variable than for adults with hearing impairments using similar devices. It is difficult to interpret children's speech-perception scores without considering the effects of lexical knowledge and speech-production abilities on their responses. This study postulated a simple mathematical model to describe the effects of hearing, lexical knowledge, and speech production on the perception test scores for monosyllabic words by children with impaired hearing. Thirty-three primary-school children with impaired hearing, fitted with hearing aids and/or cochlear implants, were evaluated using speech-perception, reading-aloud, speech-production, and language measures. These various measures were incorporated in the mathematical model, which revealed that performance in an open-set word-perception test in the auditory-alone mode is strongly dependent on residual hearing levels, lexical knowledge, and speech-production abilities. Further applications of the model provided an estimate of the effect of each component on the overall speech-perception score for each child.

The fine art of conversation: the pragmatic skills of school-aged children with hearing loss

This chapter synthesizes the findings of a number of recent studies conducted by the authors. The focus will be on spoken interactions between school-aged students who are deaf and hard of hearing, and their hearing peers. Many of the participants in these studies have worn hearing aids and/or cochlear implants since infancy and have been educated in inclusive settings. The context of these studies includes face-to-face interactions during a question/answer game, in free conversation, and during an expository task. This chapter will examine the verbal and nonverbal conversational skills 'of these students within these different contexts. Using a range of quantitative and qualitative analyses, the development of pragmatic skills in students with hearing loss will be documented, and possible implications for language support and the development of social skills will be discussed.

Finite element modeling of a generic stemless hip implant design in comparison with conventional hip implants

In this study, the finite element modeling and comparison of the stress and strain analyses were carried out for three different structures that are intact bone, stemless implant and stemmed one. Currently proposed stemless design studied here is the generic concept of stemless implant. This generic stemless implant reconstruction was numerically compared to the conventional stemmed implant and also to the intact bone as control solution. Two loading conditions were applied to the most proximal part of the models, while the most distal part was fixed for all degrees of freedom. The models were divided into two regions and studied along two paths of medial and lateral aspect. The results of this study showed that the stemless implant had less deviation from the control solution of the bone in all regions and in both loading conditions, comparing to the large deviation of the stemmed implant from the intact bone. However, it was shown that the fixation of this type of implant and its effect on sub-trochanter region must be carefully considered for designing the final product of any specific design of stemless implant.

In vitro cytotoxicity of binary TI alloys for bone implants

Interest in using titanium (Ti) alloys as load-bearing implant materials has increased due to their high strength to weight ratio, lower elastic modulus, and superior biocompatibility and enhanced corrosion resistance compared to conventional metals such as stainless steel and Co-Cr alloys. In the present study, the in vitro cytotoxicity of five binary titanium alloys, Ti15Ta, Ti15Nb, Ti15Zr, Ti15Sn and Ti15Mo, was assessed using human osteosarcoma cell line, SaOS-2 cells. The Cell proliferation and viability were determined, and cell adhesion and morphology on the surfaces of the binary Ti alloys after cell culture were observed by SEM. Results indicated that the Ti binary alloys of Ti15Ta, Ti15Nb and Ti15Zr exhibited the same level of excellent biocompatibility; Ti15Sn alloy exhibited a moderate biocompatibility while Ti15Mo alloy exhibited a moderate cytotoxicity. The SaOS-2 osteoblast-like cells had flattened and spread across the surfaces of the Ti15Ta, Ti15Nb, Ti15Zr and Ti15Sn groups; however, the cell shapes on the Ti15Mo alloy was shrinking and unhealthy. These results indicated that the Mo contents should be limited to a certain level in the design and development of new Ti alloys for implant material applications.

Novel sphene coatings on Ti–6Al–4V for orthopedic implants using sol–gel method

Hydroxyapatite (HAp) is commonly used to coat titanium alloys (Ti–6Al–4V) for orthopedic implants. However, their poor adhesion strength and insufficient long-term stability limit their application. Novel sphene (CaTiSiO₅) ceramics possess excellent chemical stability and cytocompatibility. The aim of this study is to use the novel sphene ceramics as coatings for Ti–6Al–4V. The sol–gel method was used to produce the coatings and the thermal properties, phase composition, microstructure, thickness, surface roughness and adhesion strength of sphene coatings were analyzed by differential thermal analysis–thermal gravity (DTA–TG), X-ray diffraction (XRD), scanning electron microscopy (SEM), atom force microscopy (AFM) and scratch test, respectively. DTA analysis confirmed that the temperature of the sphene phase formation is 875 °C and XRD analysis indicated pure sphene coatings were obtained. A uniform structure of the sphene coating was found across the Ti–6Al–4V surface, with a thickness and surface roughness of the coating of about 0.5–1 μm and 0.38 μm, respectively. Sphene-coated Ti–6Al–4V possessed a significantly improved adhesion strength compared to that for HAp coating and their chemical stability was evaluated by testing the profile element distribution and the dissolution kinetics of calcium (Ca) ions after soaking the sphene-coated Ti–6Al–4V in Tris–HCl solution. Sphene coatings had a significantly improved chemical stability compared to the HAp coatings. A layer of apatite formed on the sphene-coated Ti–6Al–4V after they were soaked in simulated body fluids (SBF). Our results indicate that sol–gel coating of novel sphene onto Ti–6Al–4V possessed improved adhesion strength and chemical stability, compared to HAp-coated Ti–6Al–4V prepared under the same conditions, suggesting their potential application as coatings for orthopedic implants.

Particulate-reinforced titanium composites for orthopaedic implants

In the present study, to enhance the strength of porous pure titanium scaffolds with high porosity, new particulate-reinforced Ti-based composites with the addition of biocompatible oxide particles such as TiO₂, SiO₂, ZrO₂ and Nb₂O₅ were prepared using a powder metallurgical method. The strengths of the new particulate-reinforced titanium composites were found to be significantly higher than that of pure titanium with an excellent biocompatibility. SaOS-2 osteoblast-like cells grew and spread well on the surfaces of the new particulate-reinforced titanium composites. The present study illustrated the feasibility of using the particulate-reinforced titanium composites as an orthopaedic implant material.

3D fibrous structures as cardiovascular implants

Medical textiles are a highly specialised stream of technical textiles industry with a growing range of applications. A significant advancement has been achieved in surgical products or biomedical textiles (implantable/non-implantable) with the advent of 3D textile manufacturing techniques. Cardiovascular soft tissue implants (vascular grafts) have been a field of interest over decades for use of innovative 3D tubular structures in treatment of cardiovascular diseases. In the field of soft tissue implants, knitted and woven tubular structures are being used for large diameter blood vessel replacements. Advent of electrospinning and tissue engineering techniques has been able to provide promising answers to small diameter vascular grafts. The aim of this review is to outline the approaches in vascular graft development utilising different 3D tubular structure forming techniques. The emphasis is on vascular graft development techniques that can help improve treatment efficacy in future.

Design of a miniature UHF PIFA for DBS implants

This paper presents design and simulation of a miniature rectangular spiral planar inverted-F antenna (PIFA) at UHF RFID band (902.75 - 927.25 MHz) for integration in batteryless deep brain stimulation implants. Operation in the UHF band offers small antenna size and longer transmission range. The proposed antenna has the dimensions of 10 mm × 11.5 mm × 1.6 mm, resonance frequency of 920 MHz with a bandwidth of 18 MHz at return loss of -10 dB. A dielectric substrate of FR-4 of εr = 4.5 and δ = 0.018 with thickness of 1.5644 mm is used in this design. The resonance, radiation characteristics as well as the specific absorption rate distribution induced by the designed antenna within a four layer spherical head model is evaluated by using electromagnetic modeling software which employs the finite element method.

Compact stacked planar inverted-F antenna for passive deep brain stimulation implants

A compact meandered three-layer stacked circular planar inverted-F antenna is designed and simulated at the UHF band (902.75 – 927.25 MHz) for passive deep brain stimulation implants. The UHF band is used because it offers small antenna size, and high data rate. The top and middle radiating layers are meandered, and low cost substrate and superstrate materials are used to limit the radius and height of the antenna to 5 mm and 1.64 mm, respectively. A dielectric substrate of FR-4 of εr= 4.7 and δ= 0.018, and a biocompatible superstrate of silicone of er= 3.7 and d= 0.003 with thickness of 0.2 mm are used in the design. The resonance frequency of the proposed antenna is 918 MHz with a bandwidth of 24 MHz at return loss of −10 dB in free space. The antenna parameter such as 3D gain pattern of the designed antenna within a skin-tissue model is evaluated by using the finite element method. The compactness, wide bandwidth, round shape, and stable characteristics in skin make this antenna suitable for DBS. The feasibility of the wireless power transmission to the implant in the human head is also examined.

Surgical treatment of lateral clavicle fractures associated with complete coracoclavicular ligament disruption: clinico-radiological outcomes of acromioclavicular joint sparing and spanning implants

Distal clavicle fracture associated with complete coracoclavicular ligament disruption represents an unstable injury, and osteosynthesis is recommended. This study was performed (1) to retrospectively analyse the clinico-radiological outcomes of two internal fixation techniques, and (2) to identify and analyse radiographic fracture patterns of fracture that are associated with this injury. Conclusions: Internal fixation of this fracture pattern is associated with a high union rate and favorable clinical outcomes with both techniques. A combination of distal radius plate and ligament reconstruction device resulted in stable fixation and significantly lower reoperation rates, and should be used when fracture geometry permits (Types 1 and 2).