Conclusions and Future Prospects
The achievements that have been made to date in restoration of function in the sensory and motor systems reflect a technology still in its infancy. Researchers in this emerging field have provided proof of concept in animal and human experimentation, demonstrating that it is possible to intervene in the CNS and PNS to restore limited sensation to individuals with profound deafness and blindness, or to produce simple movements in the motor system. Clearly, much work needs to be done before these systems can be considered as standard therapeutic approaches in clinical medicine.
The UEA and USEA are prototype examples of neural interfaces that can begin to selectively communicate with large numbers of individual neurons, or with small groups of neurons and nerve fibers. Importantly, the electrodes in these neural interfaces are, in fact, foreign bodies that tend to be rejected by the host's immune system. Future-generation electrode arrays must be designed to deal with this immunological challenge in a way that allows the implanted devices to function for decades. Such solutions might involve new array architectures or new coatings that present a more biocompatible interface to the neural tissues.[48,49]
Work is ongoing to develop wireless versions of neuroprosthetic devices, an essential requirement for clinical systems.[50] It will be necessary to create miniaturized signal-processing electronics and computer algorithms that can take advantage of the high-electrode-count microelectrode arrays that have already been developed or will be developed over the next decade. The design of fault-tolerant active electronics also represents a challenge: circuits must consume very little power and produce very little heat. The electronic circuitry must be hermetically sealed so that it can function flawlessly for decades in the corrosive environment of the cerebrospinal fluid. New application-specific electrode array architectures need to be developed that will be tailor-made for different implant sites throughout the entire nervous system. Improved surgical techniques need to be developed that will allow neurosurgeons to implant these devices rapidly and safely in the CNS and PNS. Although work has begun on these and many other fundamental areas, the field of neuroprosthetics is in its infancy and much remains to be done.
In the next decade, it is anticipated that neuroprosthetic technology will be applied to a variety of targets in the nervous system, including bladder and bowel control, pacing of the diaphragm, stimulation of the vagus nerve for control of epilepsy and chronic depression, stimulation of the auditory nerve and cochlear nucleus for an improved auditory prosthesis, recording from and stimulation of epileptic foci to control seizures, and recording from the motor cortex to control external devices (wheelchairs or computers) or to control electrode arrays implanted in the PNS. This emerging technology is expected to provide the neurosurgeon with entirely new sets of tools to deal with the many nervous system dysfunctions that afflict mankind.
Nat Clin Pract Neurol. 2007;3(8):444-452. © 2007 Nature Publishing Group
Cite this: Technology Insight: Future Neuroprosthetic Therapies for Disorders of the Nervous System - Medscape - Aug 01, 2007.
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