LifeHand

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LifeHand is a prosthetic hand project that allows patients to use an artificial hand to perform daily tasks, but also grants the patient the ability to sense what they are touching. This specific type of prosthetic is called a neuroprosthetic; it's a type of prosthetic that uses a neurological connection between the user and the prosthetic hand to allow the sense of touch. With sensory feedback, the artificial hand allows the user to perceive these senses due to the connection between the patient and the prosthetic. The project was developed/experimented on in the city of Rome, by European researchers from SSSA along with other research centers throughout Europe. There were two LifeHand models that were constructed (The first called LifeHand, developed in 2008, and the second called LifeHand 2, developed in 2014). The results of the LifeHand experiments were worked on for over a decade and have since been published. [1]

Contents

Development/Inner workings

The LifeHand project contains 3 complex components that involve the relationship between nerves and electric signals, intracortical microsimulation, and sensory feedback. All of these components play an important role in how the LifeHand works and require copious amounts of research to be able to function by themselves.

Beginnings of Neuroprosthetics

Due to decades of study and research in the past, neuroprosthetics are now in the foreseeable future and can prove to be extremely useful. The idea behind neuroprosthetics is that a person can regain the sense of feeling by using a prosthetic that is connected to the patient's brain. Herman Von HelmHoltz had started the idea of neuroprosthetics because of his research involving running a nerve fiber current into a dissected frog's calf muscle. This resulted in the contraction of the muscle. [2] HelmHoltz concluded that the relationship between both the muscle and nervous system was linked because of the electrical activity that occurs between the two. Since then, experiments based on his results have provided the foundation for the LifeHand project, since many of its components involve the idea of the relation between nerves, muscles, and electrical signals.

The Relationship Between Nerves and Electric signals

The LifeHand project rests upon the relationship between electric signals and nerves. The concepts of intracortical microstimulation and intraneural stimulation both require knowledge of how both nerves and electric signals interact. First, nerves are a part of everyone's body and are used as wires that send electric signals from your brain to the rest of the body. All the nerves within the body make up the nervous system. There are two types of nerves that make up this system; the motor nerves and sensory nerves. [3] For the LifeHand project, the sensory nerves are the main focus. Sensory nerves are composed of exteroceptors and mechanoreceptors that help the body perceive touch, further showing why sensory nerves are so important for the LifeHand. [4] The LifeHand (like other neuroprosthetics) uses electric signals to send signals through the nerves to a endpoint, giving off the sense that the limb is still there. [5] Since the nerves are able to interact with electrical signals, it allows for the concepts of intracortical microstimulation and intraneural stimulation be used within the LifeHand project.

Intracortical Microstimulation

Prosthetic hands in the past have been much less proficient at performing activities as normal hands, which is where research into somatosensation and intracortical microstimulation come into play. Simulating senses has only recently been a discovery for science, since lab animals were only showing results for stimulation of senses through the use of intracortical microstimulation. [6] Intracortical microstimulation (ICMS) is a type of neurorehabilitation that has been constantly researched because it allows for the rehabilitation of the limb. Initially, ICMS was researched by helping animals gain the sense of touch. The information gained from the animals was extremely useful and promising, however, researchers could not gather information in regard to what exactly the animals were feeling. After more research was done on ICMS, some changes were made, and eventually ICMS was able to be used on humans. Research involving patients who were born without a hand or lost it later in life revealed that ICMS was most effective on people who had recently lost/injured a limb. That is not to say it does not have any results with patients born without a limb, though. The LifeHand project is able to utilize this method of neurorehabilitation to allow patients to gain back sensory information and the same motor skills as an actual hand. [7] [8]

Sensory Feedback

A main focus of the LifeHand project was allowing the patient to regain the somatosensation that was lost. The idea of intraneural stimulation plays a large role in the process of regaining those senses. Intraneural stimulation (INSM) grants the flow of external information to be re-established in the patient due to electrodes that were within the arm. Real time control of the hand prothesis along with the new sensors have been tested recently to be effective with the use of INSM. Both INSM and ICMS sound similar in what they do but in reality, ICMS is how to get the patients nerves and their mind to interact with the LifeHand. While INSM involves how the external information interacts with the sensors on the LifeHand, then the interaction with those sensors and the patient's nerves. This sensory feedback falls under the umbrella of neuroengineering and provides positive results due to its ability to let the patient perceive touch; further showing its potential and why it continues to be researched. [9] INSM is still being developed but great strides have been made in its development, such as:

The last achievement in the development isn't fully completed, however, the strides to judge an objects textual features is the next major step in being that much closer to a more natural/fluid prosthesis with functioning sensory feedback. [10] [11] [12] [13]

Results

The LifeHand so far is still in development and continues to be researched in order for it to completely mimic a human hand. So far, the LifeHand is able to

  1. Manage the amount of force exerted on an object.
  2. The patient is able to understand where objects are in relation to themself.
  3. Make corrections for if they apply the wrong amount of force/pressure on an object.
  4. The patient was also able to feel and understand the shape and texture of an object.

Along with other accomplishments, the LifeHand will continue to be improved and improved until it is able to stimulate a human hand and be able to help patients with neurorehabilitation. [14]

Related Research Articles

<span class="mw-page-title-main">Perception</span> Interpretation of sensory information

Perception is the organization, identification, and interpretation of sensory information in order to represent and understand the presented information or environment. All perception involves signals that go through the nervous system, which in turn result from physical or chemical stimulation of the sensory system. Vision involves light striking the retina of the eye; smell is mediated by odor molecules; and hearing involves pressure waves.

<span class="mw-page-title-main">Prosthesis</span> Artificial device that replaces a missing body part

In medicine, a prosthesis, or a prosthetic implant, is an artificial device that replaces a missing body part, which may be lost through physical trauma, disease, or a condition present at birth. Prostheses are intended to restore the normal functions of the missing body part. Amputee rehabilitation is primarily coordinated by a physiatrist as part of an inter-disciplinary team consisting of physiatrists, prosthetists, nurses, physical therapists, and occupational therapists. Prostheses can be created by hand or with computer-aided design (CAD), a software interface that helps creators design and analyze the creation with computer-generated 2-D and 3-D graphics as well as analysis and optimization tools.

<span class="mw-page-title-main">Vestibular system</span> Sensory system that facilitates body balance

The vestibular system, in vertebrates, is a sensory system that creates the sense of balance and spatial orientation for the purpose of coordinating movement with balance. Together with the cochlea, a part of the auditory system, it constitutes the labyrinth of the inner ear in most mammals.

Cyberware is a relatively new and unknown field. In science fiction circles, however, it is commonly known to mean the hardware or machine parts implanted in the human body and acting as an interface between the central nervous system and the computers or machinery connected to it.

<span class="mw-page-title-main">Brain–computer interface</span> Direct communication pathway between an enhanced or wired brain and an external device

A brain–computer interface (BCI), sometimes called a brain–machine interface (BMI), is a direct communication pathway between the brain's electrical activity and an external device, most commonly a computer or robotic limb. BCIs are often directed at researching, mapping, assisting, augmenting, or repairing human cognitive or sensory-motor functions. They are often conceptualized as a human–machine interface that skips the intermediary component of the physical movement of body parts, although they also raise the possibility of the erasure of the discreteness of brain and machine. Implementations of BCIs range from non-invasive and partially invasive to invasive, based on how close electrodes get to brain tissue.

BrainGate is a brain implant system, currently under development and in clinical trials, designed to help those who have lost control of their limbs, or other bodily functions, such as patients with amyotrophic lateral sclerosis (ALS) or spinal cord injury. The Braingate technology and related Cyberkinetic’s assets are now owned by privately held Braingate, Co. The sensor, which is implanted into the brain, monitors brain activity in the patient and converts the intention of the user into computer commands.

Sensory substitution is a change of the characteristics of one sensory modality into stimuli of another sensory modality.

Neuroprosthetics is a discipline related to neuroscience and biomedical engineering concerned with developing neural prostheses. They are sometimes contrasted with a brain–computer interface, which connects the brain to a computer rather than a device meant to replace missing biological functionality.

Sensory processing is the process that organizes and distinguishes sensation from one's own body and the environment, thus making it possible to use the body effectively within the environment. Specifically, it deals with how the brain processes multiple sensory modality inputs, such as proprioception, vision, auditory system, tactile, olfactory, vestibular system, interoception, and taste into usable functional outputs.

Neural engineering is a discipline within biomedical engineering that uses engineering techniques to understand, repair, replace, or enhance neural systems. Neural engineers are uniquely qualified to solve design problems at the interface of living neural tissue and non-living constructs.

Bio-mechatronics is an applied interdisciplinary science that aims to integrate biology and mechatronics. It also encompasses the fields of robotics and neuroscience. Biomechatronic devices cover a wide range of applications, from developing prosthetic limbs to engineering solutions concerning respiration, vision, and the cardiovascular system.

Targeted reinnervation enables amputees to control motorized prosthetic devices and to regain sensory feedback. The method was developed by Dr. Todd Kuiken at Northwestern University and Rehabilitation Institute of Chicago and Dr. Gregory Dumanian at Northwestern University Division of Plastic Surgery.

Body schema is an organism's internal model of its own body, including the position of its limbs. The neurologist Sir Henry Head originally defined it as a postural model of the body that actively organizes and modifies 'the impressions produced by incoming sensory impulses in such a way that the final sensation of body position, or of locality, rises into consciousness charged with a relation to something that has happened before'. As a postural model that keeps track of limb position, it plays an important role in control of action.

Tactile discrimination is the ability to differentiate information through the sense of touch. The somatosensory system is the nervous system pathway that is responsible for this essential survival ability used in adaptation. There are various types of tactile discrimination. One of the most well known and most researched is two-point discrimination, the ability to differentiate between two different tactile stimuli which are relatively close together. Other types of discrimination like graphesthesia and spatial discrimination also exist but are not as extensively researched. Tactile discrimination is something that can be stronger or weaker in different people and two major conditions, chronic pain and blindness, can affect it greatly. Blindness increases tactile discrimination abilities which is extremely helpful for tasks like reading braille. In contrast, chronic pain conditions, like arthritis, decrease a person's tactile discrimination. One other major application of tactile discrimination is in new prosthetics and robotics which attempt to mimic the abilities of the human hand. In this case tactile sensors function similarly to mechanoreceptors in a human hand to differentiate tactile stimuli.

Microstimulation is a technique that stimulates a small population of neurons by passing a small electrical current through a nearby microelectrode.

A visual prosthesis, often referred to as a bionic eye, is an experimental visual device intended to restore functional vision in those with partial or total blindness. Many devices have been developed, usually modeled on the cochlear implant or bionic ear devices, a type of neural prosthesis in use since the mid-1980s. The idea of using electrical current to provide sight dates back to the 18th century, discussed by Benjamin Franklin, Tiberius Cavallo, and Charles LeRoy.

Sensory stimulation therapy (SST) is an experimental therapy that aims to use neural plasticity mechanisms to aid in the recovery of somatosensory function after stroke or cognitive ageing. Stroke and cognitive ageing are well known sources of cognitive loss, the former by neuronal death, the latter by weakening of neural connections. SST stimulates a specific sense at a specific frequency. Research suggests that this technique may reverse cognitive ageing by up to 30 years, and may selectively improve or impair two point discrimination thresholds.

A cortical implant is a subset of neuroprosthetics that is in direct connection with the cerebral cortex of the brain. By directly interfacing with different regions of the cortex, the cortical implant can provide stimulation to an immediate area and provide different benefits, depending on its design and placement. A typical cortical implant is an implantable microelectrode array, which is a small device through which a neural signal can be received or transmitted.

<span class="mw-page-title-main">Stéphanie P. Lacour</span> French neurotechnologist

Stéphanie P. Lacour is a French neurotechnologist and full professor holding the Foundation Bertarelli Chair in Neuroprosthetic Technology at the Swiss Federal Institute of Technology in Lausanne (EPFL). Lacour is a pioneer in the field of stretchable electronics and directs a laboratory at EPFL which specializes in the development of Soft BioElectronic Interfaces to enable seamless integration of neuroprosthetic devices into human tissues. Lacour is also a co-founding member and director of the Center for Neuroprosthetics at the EPFL Satellite Campus in Geneva, Switzerland.

Sliman Julien Bensmaia was a French-Algerian neuroscientist. An international expert in the neural encoding of sensory information and a pioneer in robotic neuroprosthetics, his nearly 100 academic articles in somatosensation have been cited over 10,000 times. He is the principal architect of the biomimetic approach to naturalistic restoration of the sensations of touch and proprioception in amputees and paralyzed patients.

References

  1. ↑ "A prosthetic that restores the sense of where your hand is - Robohub". robohub.org. Retrieved 2023-10-22.
  2. ↑ Radovic, Tamara "Neuroprosthetics: The Restoration of Brain damage" University of California, Merced https://escholarship.org/content/qt7553d0qc/qt7553d0qc.pd page 2-3, 2022-01-07
  3. ↑ "Nerves: Types, Function & Anatomy". Cleveland Clinic. Retrieved 2023-11-09.
  4. ↑ Washmuth, Dan (August 10, 2022). "Sensory nerves". Study.com. Retrieved August 10, 2022.
  5. ↑ Grill, W. M.; Kirsch, R. F. (2000). "Neuroprosthetic applications of electrical stimulation". Assistive Technology. 12 (1): 6–20. doi:10.1080/10400435.2000.10132006. ISSN   1040-0435. PMID   11067578. S2CID   33902681.
  6. ↑ "This cybernetic hand is the first to give amputees a sense of touch". Gizmodo. 2014-02-05. Retrieved 2023-10-22.
  7. ↑ Oddo, Calogero Maria; Raspopovic, Stanisa; Artoni, Fiorenzo; Mazzoni, Alberto; Spigler, Giacomo; Petrini, Francesco; Giambattistelli, Federica; Vecchio, Fabrizio; Miraglia, Francesca; Zollo, Loredana; Di Pino, Giovanni; Camboni, Domenico; Carrozza, Maria Chiara; Guglielmelli, Eugenio; Rossini, Paolo Maria (2016-03-08). Brown, Emery N (ed.). "Intraneural stimulation elicits discrimination of textural features by artificial fingertip in intact and amputee humans". eLife. 5: e09148. doi: 10.7554/eLife.09148 . ISSN   2050-084X. PMC   4798967 . PMID   26952132.
  8. ↑ Flesher, Sharlene; Collinger, Jennifer; Weiss, Jeffrey; Hughes, Christopher; Bensmaia, Sliman; Boninger, Michael; Gaunt, Robert (September 2017). "Restoring Touch through Intracortical Microstimulation of Human Somatosensory Cortex". 2017 New Generation of CAS (NGCAS). IEEE. pp. 185–188. doi:10.1109/ngcas.2017.68. ISBN   978-1-5090-6447-2. S2CID   25225745.
  9. ↑ "A prosthetic that restores the sense of where your hand is - Robohub". robohub.org. Retrieved 2023-11-08.
  10. ↑ Ochoa, José L. (2010-02-19). "Intraneural microstimulation in humans". Neuroscience Letters. Microneurography: a relevant tool for the understanding of Neuropathic Pain. 470 (3): 162–167. doi:10.1016/j.neulet.2009.10.007. ISSN   0304-3940. PMC   3480217 . PMID   19818832.
  11. ↑ Oddo, Calogero Maria; Raspopovic, Stanisa; Artoni, Fiorenzo; Mazzoni, Alberto; Spigler, Giacomo; Petrini, Francesco; Giambattistelli, Federica; Vecchio, Fabrizio; Miraglia, Francesca; Zollo, Loredana; Di Pino, Giovanni; Camboni, Domenico; Carrozza, Maria Chiara; Guglielmelli, Eugenio; Rossini, Paolo Maria (2016-03-08). Brown, Emery N (ed.). "Intraneural stimulation elicits discrimination of textural features by artificial fingertip in intact and amputee humans". eLife. 5: e09148. doi: 10.7554/eLife.09148 . ISSN   2050-084X. PMC   4798967 . PMID   26952132.
  12. ↑ Strauss, I.; Valle, G.; Artoni, F.; D’Anna, E.; Granata, G.; Di Iorio, R.; Guiraud, D.; Stieglitz, T.; Rossini, P. M.; Raspopovic, S.; Petrini, F. M.; Micera, S. (2019-12-17). "Characterization of multi-channel intraneural stimulation in transradial amputees". Scientific Reports. 9 (1): 19258. Bibcode:2019NatSR...919258S. doi:10.1038/s41598-019-55591-z. ISSN   2045-2322. PMC   6917705 . PMID   31848384.
  13. ↑ Ochoa, Jose (8 October 2009). "Intraneural microstimulation in humans". Neuroscience Letters. 470 (3): 162–167. doi:10.1016/j.neulet.2009.10.007. PMC   3480217 . PMID   19818832.
  14. ↑ "LifeHand 2" (PDF). Scuola Superiore Sant'Anna.
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