Biology Reference
In-Depth Information
4. BIOMEDICAL APPLICATIONS OF NERVE INTERFACES
Both PNS and CNS dysfunctions by disease, trauma, or injury pro-
duce impairments in the ADL. Applications of nerve interfaces linked with
neuroprosthetic systems can adopt two main approaches: (1) replacement of
central control after CSN injuries by FES systems that stimulate the intact
peripheral nerves or muscles, generating movements or functions that repro-
duce normal actions and (2) replacement of injured peripheral nerves by
connecting proximal nerve segments with denervated muscles or artificial
prostheses substituting lost parts of the body (
Fig. 2.2
). Regain of control
in micturition and defecation, walking improvement after gait impairment
or paraplegia, and also prosthetic substitution after loss of a limb are some of
the topics that have been addressed by trying to electronically interface
remaining nerve pathways and using different prosthetic devices. Moreover,
not only efferent signals are targeted to elicit functional activities, but also
recording of afferent signals is aimed to provide sensory information and
produce a bidirectional interface with the nervous system, and electrical
modulation of disturbed neural circuits is being increasingly applied to dif-
ferent neural disorders in exciting and challenging biomedical applications.
4.1. Applications for CNS-injured patients
Both brain and spinal cord injuries induce significant neurological and func-
tional disability from which full recovery is far from being expected. FES
relies on electrical stimulation of a nerve or a muscle that either has lost
Figure 2.2 Schematic representation of the two main application modes of peripheral
nerve interface systems, represented for the control of the hand by a functional elec-
trical stimulation system in a tetraplegic case, and for the control of a bionic prosthesis
in an amputee.
