Neuro-electronic technology in medicine and beyond

This dissertation looks at the technology and social issues involved with interfacing electronics directly to the human nervous system, in particular the methods for both reading and stimulating nerves. The development and use of cochlea implants is discussed, and is compared with recent developments in artificial vision. The final sections consider a future for non-medicinal applications of neuro-electronic technology. Social attitudes towards use for both medicinal and non-medicinal purposes are discussed, and the viability of use in the latter case assessed

Electrical vestibular stimulation in humans. A narrative review

Background: In patients with bilateral vestibulopathy, the regular treatment options, such as medication, surgery, and/ or vestibular rehabilitation, do not always suffice. Therefore, the focus in this field of vestibular research shifted to electri- cal vestibular stimulation (EVS) and the development of a system capable of artificially restoring the vestibular func- tion. Key Message: Currently, three approaches are being investigated: vestibular co-stimulation with a cochlear im- plant (CI), EVS with a vestibular implant (VI), and galvanic vestibular stimulation (GVS). All three applications show promising results but due to conceptual differences and the experimental state, a consensus on which application is the most ideal for which type of patient is still missing. Summa- ry: Vestibular co-stimulation with a CI is based on “spread of excitation,” which is a phenomenon that occurs when the currents from the CI spread to the surrounding structures and stimulate them. It has been shown that CI activation can indeed result in stimulation of the vestibular structures. Therefore, the question was raised whether vestibular co- stimulation can be functionally used in patients with bilat- eral vestibulopathy. A more direct vestibular stimulation method can be accomplished by implantation and activa- tion of a VI. The concept of the VI is based on the technology and principles of the CI. Different VI prototypes are currently being evaluated regarding feasibility and functionality. So far, all of them were capable of activating different types of vestibular reflexes. A third stimulation method is GVS, which requires the use of surface electrodes instead of an implant- ed electrode array. However, as the currents are sent through the skull from one mastoid to the other, GVS is rather unspe- cific. It should be mentioned though, that the reported spread of excitation in both CI and VI use also seems to in- duce a more unspecific stimulation. Although all three ap- plications of EVS were shown to be effective, it has yet to be defined which option is more desirable based on applicabil- ity and efficiency. It is possible and even likely that there is a place for all three approaches, given the diversity of the pa- tient population who serves to gain from such technologies

Efficacy of speech intervention using electropalatography with a cochlear implant user

Electropalatography (EPG) has become relatively well established as a safe and convenient technique for use in the assessment, diagnosis and treatment of children and adults with articulation disorders. EPG's wide applicability is reflected in the range of different cases that has been researched in recent years. Some research has been carried out using EPG therapy for deaf individuals who use hearing aids, however there are no similar studies for cochlear implant users. The purpose of this single case study is to explore the technique of EPG as a therapeutic intervention to treat voiceless velar stop consonant sound production in a deaf child cochlear implant user. EPG therapy was offered as a last resort when traditional therapy failed to achieve specific changes. During therapy, a list of familiar words was practised, using the visual feedback provided by EPG. The client's articulation was assessed using objective (EPG printouts) and subjective (listener ratings) measures at four assessment points. Changes were found to be statistically significant. Generalization of the newly‐acquired skills to untaught words containing voiceless velars was also observed. The results are discussed in the broader context of implications of this type of therapy with deaf clients

An Energy-Efficient, Dynamic Voltage Scaling Neural Stimulator for a Proprioceptive Prosthesis

Accepted versio

EDUCATING HEALTH CARE PROFESSIONALS ON IMPLANTABLE HEARING SOLUTIONS TO INCREASE APPROPRIATE REFERRAL RATES IN ADULTS

Despite being an available hearing treatment option for several decades, there is still an underutilization of cochlear implants within the population of adults with hearing loss that would meet candidacy criteria. Only 8% of people that are cochlear implant candidates utilize cochlear implants. Thus, it is important to examine why underutilization occurs and how to solve the problem. The current doctoral scholarly project aims to educate health care professionals, with targeted audiences of hearing instrument specialists and primary care practitioners, on cochlear implants, outcomes, and candidacy. Narrated PowerPoint presentation videos were created as a way to educate health care professionals on cochlear implants. Sharing presentations such as these could be one way that an audiologist could educate local health care practitioners to boost cochlear implant candidacy referral rates in his/her area. This would also lead to an increase in use of implantable hearing solutions in adult populations that could stand to benefit tremendously from this technology

Evaluating and Improving Cochlear Length Measurements on Clinical Computed Tomography Images

Cochlear implants provide the sensation of sound to deaf individuals. An accurate estimate of cochlear duct length (CDL) is required for pre-operative implant electrode selection and can be obtained from clinical computed tomography (CT) by measuring the “A-value”. The objectives of this work were to estimate the accuracy and variability in manual A-value measurements, and to automate measurements. Four specialists repeatedly measured the A-value on clinical CT images from which the inter- and intra-observer variability were calculated. Accuracy was assessed by comparison to measurements on higher resolution micro-CT images. Motivated by this study, software was developed to automate the A-value measurement by registering an annotated atlas to unlabelled images. There was significant variability in manual A-value measurements made using either standard clinical or multi-planar reformatted views with the latter exhibiting higher variability but better accuracy. The automated approach eliminated variability and improved accuracy, enabling the correct selection of electrode length

Tinnitus in cochlear implantees: cognitive behavioural therapy for cochlear implant users

Background to the study: Cochlear implants (CI) can help to suppress tinnitus and often make existing tinnitus more bearable. However, a number of patients still suffer from tinnitus afterwards. In some cases the implantation makes existing tinnitus worse, or tinnitus may occur as a result of cochlear implantation. Because of the inconclusive aetiology of tinnitus it is difficult to treat its effects. So far, one of the most popular treatments for tinnitus is the widely used Cognitive Behavioural Therapy (CBT), which aims to influence dysfunctional emotions, behaviours and cognitions though a goal-orientated, systematic procedure. CBT aims to minimize the side-effects of tinnitus and help to manage it in a more efficient way. CBT has been investigated in several studies and shows promising results in reducing the debilitating effect of tinnitus. CBT has not yet been used specifically for, or investigated in, relation to treating CI users suffering from tinnitus.Aims and outline of the study: Our research aimed to investigate CBT’s effectiveness for cochlear implant users. Using a randomized control trial, we investigated whether two-hour Tinnitus Workshops for the control group were as equally as effective as CBT for the research group. We also explored if either type of treatment for cochlear implant users needed any modifications to make them more suitable for this group of tinnitus sufferers. Using Open Questions, we investigated tinnitus in cochlear implant users. We analysed the Open Questions from both groups, creating a profile of a typical cochlear implant user who suffers from tinnitus, and we also explored whether both interventions (Tinnitus Workshop or CBT) were suitable for this kind of patient. Data was gathered, pre- and post-interventions, by questionnaires; these were Tinnitus Questionnaires (TQ), Visual Analogue Scale (VAS), Quality of Life Short Form 36 Health Survey (SF-36) and Hospital Anxiety and Depression Scale (HADS). Results: In the control group, we found no significant differences between the TQ scores pre- and post-intervention. VAS scores post-intervention were lower than pre-intervention, indicating some improvement in individual tinnitus perception; however, the difference was not significant. In the research group, we found small, but not significant, differences in both TQ pre- and post-intervention (z =1.83, p>.05) and in VAS (z=0.14, p>.05). No significant differences were found between the control and the research group pre- and post-intervention. Conclusions: The questionnaires used in this study, such as TQ or VAS, showed a decrease in general tinnitus distress, but a larger-sized sample group may be needed for greater statistical certainty. The results from the Open Questions showed that cochlear implant users were affected by tinnitus in a similar way to non-cochlear implant users. Overall, both interventions need further, small modifications and adjustments to their protocols in order to be more effective for this type of tinnitus sufferer