An efficient telemetry system for restoring sight

PhD ThesisThe human nervous system can be damaged as a result of disease or trauma, causing conditions such as Parkinson’s disease. Most people try pharmaceuticals as a primary method of treatment. However, drugs cannot restore some cases, such as visual disorder. Alternatively, this impairment can be treated with electronic neural prostheses. A retinal prosthesis is an example of that for restoring sight, but it is not efficient and only people with retinal pigmentosa benefit from it. In such treatments, stimulation of the nervous system can be achieved by electrical or optical means. In the latter case, the nerves need to be rendered light sensitive via genetic means (optogenetics). High radiance photonic devices are then required to deliver light to the target tissue. Such optical approaches hold the potential to be more effective while causing less harm to the brain tissue. As these devices are implanted in tissue, wireless means need to be used to communicate with them. For this, IEEE 802.15.6 or Bluetooth protocols at 2.4GHz are potentially compatible with most advanced electronic devices, and are also safe and secure. Also, wireless power delivery can operate the implanted device. In this thesis, a fully wireless and efficient visual cortical stimulator was designed to restore the sight of the blind. This system is likely to address 40% of the causes of blindness. In general, the system can be divided into two parts, hardware and software. Hardware parts include a wireless power transfer design, the communication device, power management, a processor and the control unit, and the 3D design for assembly. The software part contains the image simplification, image compression, data encoding, pulse modulation, and the control system. Real-time video streaming is processed and sent over Bluetooth, and data are received by the LPC4330 six layer implanted board. After retrieving the compressed data, the processed data are again sent to the implanted electrode/optrode to stimulate the brain’s nerve cells

Information transmission in normal vision and optogenetically resensitised dystrophic retinas

Phd ThesisThe retina is a sophisticated image processing machine, transforming the visual scene as detected by the photoreceptors into a pattern of action potentials that is sent to the brain by the retinal ganglion cells (RGCs), where it is further processed to help us understand and navigate the world. Understanding this encoding process is important on a number of levels. First, it informs the study of upstream visual processing by elucidating the signals higher visual areas receive as input and how they relate to the outside world. Second, it is important for the development of treatments for retinal blindness, such as retinal prosthetics. In this thesis, I present work using multielectrode array (MEA) recordings of RGC populations from ex-vivo retinal wholemounts to study various aspects of retinal information processing. My results fall into two main themes. In the rst part, in collaboration with Dr Geo rey Portelli and Dr Pierre Kornprobst of INRIA, I use ashed gratings of varying spatial frequency and phase to compare di erent coding strategies that the retina might use. These results show that information is encoded synergistically by pairs of neurons and that, of the codes tested, a Rank Order Code based on the relative order of ring of the rst spikes of a population of neurons following a stimulus provides information about the stimulus faster and more e ciently than other codes. In the later parts, I use optogenetic stimulation of RGCs in congenitally blind retinas to study how visual information is corrupted by the spontaneous hyperactivity that arises as a result of photoreceptor degeneration. I show that by dampening this activity with the gap junction blocker meclofenamic acid, I can improve the signal-to-noise ratio, spatial acuity and contrast sensitivity of prosthetically evoked responses. Taken together, this work provides important insights for the future development of retinal prostheses

Biomedical Engineering

Biomedical engineering is currently relatively wide scientific area which has been constantly bringing innovations with an objective to support and improve all areas of medicine such as therapy, diagnostics and rehabilitation. It holds a strong position also in natural and biological sciences. In the terms of application, biomedical engineering is present at almost all technical universities where some of them are targeted for the research and development in this area. The presented book brings chosen outputs and results of research and development tasks, often supported by important world or European framework programs or grant agencies. The knowledge and findings from the area of biomaterials, bioelectronics, bioinformatics, biomedical devices and tools or computer support in the processes of diagnostics and therapy are defined in a way that they bring both basic information to a reader and also specific outputs with a possible further use in research and development

Wireless Technologies for Implantable Devices

Wireless technologies are incorporated in implantable devices since at least the 1950s. With remote data collection and control of implantable devices, these wireless technologies help researchers and clinicians to better understand diseases and to improve medical treatments. Today, wireless technologies are still more commonly used for research, with limited applications in a number of clinical implantable devices. Recent development and standardization of wireless technologies present a good opportunity for their wider use in other types of implantable devices, which will significantly improve the outcomes of many diseases or injuries. This review briefly describes some common wireless technologies and modern advancements, as well as their strengths and suitability for use in implantable medical devices. The applications of these wireless technologies in treatments of orthopedic and cardiovascular injuries and disorders are described. This review then concludes with a discussion on the technical challenges and potential solutions of implementing wireless technologies in implantable devices