Sensory neuroprostheses: from physiology to clinical application

Our senses are the main information channels through which we perceive and interact with the world. Consequently, patients suffering from severe sensory disabilities are limited at numerous levels of physical and social functioning. This has motivated the development of a novel therapeutic alternative: sensory neuroprostheses. In order to restore lost function, sensory neuroprostheses attempt to take advantage of the information transfer pathway common to all senses: (1) transduction of the physical stimulus by sensory receptors, (2) transmission of relevant information to the primary sensory areas in the brain by sensory afferents, and (3) analysis and integration of the information to generate perception and action. Neurosensory deficits might occur upon damage of any of the structures involved in the process. However, damage to the peripheral sensory receptor can be often the cause of neurosensory loss. Sensory neuroprostheses attempt to “replace” the malfunctioning or missing peripheral sensory organ by directly delivering basic sensory information to the brain using electrical currents. If the prosthesis is able to deliver enough consistent information, the brain will correctly interpret it and useful rehabilitation can be achieved. I have had the opportunity to contribute to this multidisciplinary field at diverse aspects of the development of retinal, cochlear, and vestibular implants. I have chosen to present the main challenges related to the implementation of these devices as a step-to-step approach in the form a collection of selected articles: (1) sensory information should be efficiently delivered to peripheral afferents (Chapter 2); (2) then the expected physiological response can be evoked and quantified (Chapter 3); (3) the restoration of basic sensory abilities can lead to useful rehabilitation in meaningful every-day activities (Chapter 4); (4) however, sensory pathophysiology can fundamentally limit our ability to transmit the appropriate message to the brain (Chapter 5). Finally, Chapter 6 presents the good clinical outcomes that can be achieved, highlighting the importance of proper technical and rehabilitation follow-up. To conclude, in Chapter 7 the present and future of sensory neuroprostheses will be discussed. This will specifically include current clinical and technical challenges, future prospects, as well as the potential of these devices of improving our fundamental knowledge of sensory physiology and neurosensory deficits