[1] Neural prostheses are a series of devices that can substitute a motor, sensory or cognitive modality that might have been damaged as a result of an injury or a disease.
These implantable devices are also commonly used in animal experimentation as a tool to aid neuroscientists in developing a greater understanding of the brain and its functioning.
Accurately probing and recording the electrical signals in the brain would help better understand the relationship among a local population of neurons that are responsible for a specific function.
In 1988, the lumbar anterior root implant and functional electrical stimulation (FES) facilitated standing and walking, respectively, for a group of paraplegics.
[7] Recent systems utilize more advanced probes, such as those used in deep brain stimulation to alleviate the symptoms of Parkinson's disease.
The problem with either approach is that the brain floats free in the skull while the probe does not, and relatively minor impacts, such as a low speed car accident, are potentially damaging.
The subjects demonstrated their ability to distinguish between three common objects (plate, cup, and knife) at levels statistically above chance.
[10] The seminal experimental work towards the development of visual prostheses was done by cortical stimulation using a grid of large surface electrodes.
The requirements for a high resolution retinal prosthesis should follow from the needs and desires of blind individuals who will benefit from the device.
[12] With this new technology, several scientists, including Karen Moxon at Drexel, John Chapin at SUNY, and Miguel Nicolelis at Duke University, started research on the design of a sophisticated visual prosthesis.
In 1957, French researchers A. Djourno and C. Eyries, with the help of D. Kayser, provided the first detailed description of directly stimulating the auditory nerve in a human subject.
A combination of engineering, signal processing, biophysics, and cognitive neuroscience was necessary to produce the right balance of technology to maximize the performance of auditory prosthesis.
The concept of combining simultaneous electric-acoustic stimulation (EAS) for the purposes of better hearing was first described by C. von Ilberg and J. Kiefer, from the Universitätsklinik Frankfurt, Germany, in 1999.
In theory these devices would benefit patients with significant low-frequency residual hearing who have lost perception in the speech frequency range and hence have decreased discrimination scores.
Healers had developed specific and detailed techniques to exploit the generative qualities of the fish to treat various types of pain, including headache.
Because of the awkwardness of using a living shock generator, a fair level of skill was required to deliver the therapy to the target for the proper amount of time.
[23] This device is implanted over the sacral anterior root ganglia of the spinal cord; controlled by an external transmitter, it delivers intermittent stimulation which improves bladder emptying.
The filters used in the prostheses are also being fine-tuned, and in the future, doctors hope to create an implant capable of transmitting signals from inside the skull wirelessly, as opposed to through a cable.
[citation needed] Prior to these advancements, Philip Kennedy (Emory and Georgia Tech) had an operable if somewhat primitive system which allowed an individual with paralysis to spell words by modulating their brain activity.
These arms allow a slightly limited range of motion, and reportedly are slated to feature sensors for detecting pressure and temperature.
[26] Dr. Todd Kuiken at Northwestern University and Rehabilitation Institute of Chicago has developed a method called targeted reinnervation for an amputee to control motorized prosthetic devices and to regain sensory feedback.
In 2002 a Multielectrode array of 100 electrodes, which now forms the sensor part of a Braingate, was implanted directly into the median nerve fibers of scientist Kevin Warwick.
[27] In June 2014, Juliano Pinto, a paraplegic athlete, performed the ceremonial first kick at the 2014 FIFA World Cup using a powered exoskeleton with a brain interface.
[29] The MIT Biomechatronics Group has designed a novel amputation paradigm that enables biological muscles and myoelectric prostheses to interface neurally with high reliability.
During a standard amputation, agonist-antagonist muscles (e.g. bicep-tricep) are isolated from each other, preventing the ability to have the dynamic contract-extend mechanism that generates sensory feedback.
[32][33] Mathematical modeling of these signals is a complex task "because of the nonlinear dynamics inherent in the cellular/molecular mechanisms comprising neurons and their synaptic connections".
[citation needed] Wireless Transmission is being developed to allow continuous recording of neuronal signals of individuals in their daily life.
A small, light weight device has been developed that allows constant recording of primate brain neurons at Stanford University.
[citation needed] Local field potentials (LFPs) are electrophysiological signals that are related to the sum of all dendritic synaptic activity within a volume of tissue.
[42] Also, Rice University scientists have discovered a new method to tune the light-induced vibrations of nanoparticles through slight alterations to the surface to which the particles are attached.