According to a new report by Allied Market Research titled, "Neuroprosthetics Market- Global Opportunity Analysis and Industry Forecast, 2013- 2020," the global neuroprosthetics market is expected to reach $14 billion by 2020. High growth areas include neuroprosthetics, retinal implants and conditions like Parkinson's disease, Overactive Bladder Syndrome and Epilepsy. Many corporations and universities are teaming up to advance neuroprosthetics and while it’s a relatively new segment, growth trends are expected to continue. In order to make headway in treating neurodegenerative disorders, as well as injuries to motor, sensory or cognitive functions, neuroprosthetic devices either support or replace central nervous system functions. In effect, it is an interface between the human brain and a computer that attempts to detect and translate activity into command sequences so that prostheses can take over for failed functions.
Given an aging population and an increase in the incidence of neurological disorders, there are a variety of global governments and government associations currently driving the global neuroprosthetics industry. The backing for research is in part based on an awareness of the high cost of surgeries for sufferers. Should there be a way to effectively implant assistance for an improved quality of life, the cost would be considerably less.
There are many challenges and barriers faced by researchers and developers of neuroprosthetics. The size of the solutions must be miniscule in order to be housed in the body -- the body continually tries to eject anything foreign, and there are power considerations, communications challenges, and how the body will deal with a variety of technologies are all problematic, for example:
- Natural movements are extremely difficult to mimic without the existence of sensation.
- Large translational and rotational displacements that are involved with the spine, impact the longevity of the electrodes that can be implanted. The brain, however, does not have the same limitations.
- So far, microelectronic devices are not able to last a lifetime within the central nervous system. Wireless multi-electrode arrays are currently under development that eliminate wire interconnects and as a result chronic tissue reaction to the tethering forces of the wires.
- There is a tradeoff between the antenna size used and the depth of RF penetration. Antenna size can be a limiting factor for the size of the implant as it can take up a major part of the device’s volume.
University of Washington researchers at the National Science Foundation Center for Sensorimotor Neural Engineering (CSNE) have used direct stimulation of the human brain surface to provide basic sensory feedback via artificial electrical signals so that a patient can control movement while opening and closing their hand. This research will be the first step to a closed loop, bi-directional brain-computer interface (BBCI) enabling two-way communication between disparate nervous system parts. It will allow the brain to directly control external prosthetics to enhance movement, and possibly reanimate a paralyzed limb, while getting sensory feedback. The research, covering the first time the technology was ever used in a human patient that was awake and performing a motor task, will be published in the Oct.-Dec. 2016 issue of IEEE Transactions on Haptics.
Another research project by researchers from Harvard University and China, published in the journal Nature involves flexible electronics. To date, while flexible electronics could provide a means for conforming electronics to non-planar surfaces; delivery of flexible electronics to internal regions of the body remains difficult. The research demonstrates a syringe injection method of sub-micrometer-thick, centimeter-scale macro-porous mesh electronics through needles with a diameter as small as 100μm.
Electronic components are injected into man-made and biological cavities, as well as dense gels and tissue, with more than a 90% device yield. We demonstrate several applications of syringe-injectable electronics as a general approach for interpenetrating flexible electronics with three-dimensional structures. The electronics can be implanted in the brain/body with minimal impact on neural tissue but be used effectively for long-term microstimulation. The research is beginning to look at the possibility of eliminating active electronics on the implant since the energy transfer to the device can be on a pulse-by-pulse basis. The results could overcome the roadblocks faced by many neural prosthetic devices, as well as dramatically increase functional life.
Yet another research topic recently submitted to Frontiers in Neuroscience is a paper entitled, “Closed-loop task difficulty adaptation during virtual reality reach-to-grasp training assisted with an exoskeleton for stroke rehabilitation.” Stroke patients experiencing severe motor deficits of the upper extremity may practice rehabilitation exercises using a multi-joint exoskeleton.
A commercially available seven degree-of-freedom arm exoskeleton was used to provide passive gravity compensation during task-oriented training. During the study, five severely affected chronic stroke patients performed reach-to-grasp exercises and received virtual reality feedback from their 3-D movements. After 20 training and feedback sessions, this unsupervised training concept led to a progressive increase of the virtual training space (p<0.001) in accordance with the subjects abilities.
According to the study, “Combining gravity-compensating assistance with adaptive closed-loop feedback in virtual reality provides customized rehabilitation environments for severely affected stroke patients. This approach may facilitate motor learning by progressively challenging the subject in accordance with the individual capacity for functional restoration. It might be necessary to apply concurrent restorative interventions to translate these improvements into relevant functional gains of severely motor impaired patients in activities of daily living."
Degenerative disorders affect more than 45 million people worldwide, typically striking older adults. They involve progressive deterioration of nerve cells, eventually leading to cell death. Researchers continue to develop new and compelling treatments of these disorders and in most cases are ahead of researchers in understanding why they occur.