New approaches in augmenting human-machine interaction (HMI) have found to be extremely useful in mitigating effects of neurological diseases and injuries. Before we delve into the intricacies of these technologies, let us learn how HMI works in simple terms.
Technologies and computer systems are assuming important tasks in our everyday life and work either visibly or behind the scenes. It is well known now that the smooth communication between people and machines requires interfaces – the place where or action by which a user engages with the machine. Using certain sensors and interfaces,these machines can be controlled by a mouse, touch screens, voice, or gestures. At a more advanced level, virtual reality (VR) glasses enable engineers to walk through planned factory buildings, andchatbots reply automatically to requests from customers.
HMIinvolves interaction and communication of people and automated systems with each other. It has long ceased to be confined to just traditional machines in industry but now relates to computers, digital systems or devices thanks to the development of Internet of Things (IoT).In this system, more and more devices are inter-connected and automatically carry out tasks.
How HMI comes handy in tackling neurological diseases
Millions of people experience some form of brain-related disease during their life. Alzheimer’s disease and other neurodegenerative or age-related mental disorders are quite common nowadays. Neuromuscular diseases such as Amyotrophic lateral sclerosis (ALS) render people incapable of communication. ALS makes people eventually lose all ability to use muscles and communicate by speech, nodding, or even eyeblinks or eyegaze.
It is becoming urgent to find better ways of preventing and treating brain diseases and understanding how our brain works is important to keep our economies at the forefront of new information technologies and services.
There are many devices or systems such as neural interfaces operating at the intersection of the nervous system and an internal or external device. Interfaces like neural prosthetics are artificial extensions to the body that restore or supplement function of the nervous system lost during disease or injury.These interfaces are used to allow disabled individuals the ability to control their own bodies and lead fuller and more fulfilling lives.
The advent of BCI
Brain-Computer Interface (BCI) is an advanced form of HMI that involves the analysis and translation of brain signals into commands that are relayed to output devices that carry out desired actions. Ithas proven to be a very useful tool for providing alternative communication and mobility to patients suffering from nervous system injuries. In addition to that, BCI technology is evolving to provide therapeutic benefits by inducing cortical reorganization via neuronal plasticity. To deal more efficiently with health issues like ALS, Parkinson’s disease, spinal cord injury, stroke and disorders of consciousness, this technology has been found to be veryeffectivein tackling with neurological disorders.
BCI can be defined as a direct communication pathway between an enhanced or wired brain and an external device. Directed at researching, mapping, assisting, augmenting, or repairing human cognitive or sensory-motor function, BCI has made even complex systems easier to use. Thesemachines are able to adapt more and more towards human habits and needsand with this humans are expanding their realm of experience and field of action.
In 1924, Hans Berge was the first to record electrical activity of the human brain with development of electroencephalography (EEG). He analyzed the interrelation of alternations in EEG wave diagrams with brain diseases. In 70s, Professor Jacques Vidal coined the term “BCI,”by demonstratingsingle-neuron-based device control, enabling computers to be a prosthetic extension of the brain.
How BCI technology works?
BCI technology is used to record and analyse brain signals to determine the output that is desired by the user; for example,which letter to select for spelling a word or to indicate which direction to move a cursor and so on. The main purpose of clinical BCI systems is to help patients communicate with their environment or to aid in their recovery. BCI can be used to replace, restore, enhance, supplement or improve natural Central Neural System (CNS) output.
This signal processing stage has two phases:
The first phase is known as feature extraction which is the measurement of the characteristics of the signals that encode the output. These features can be simple measures, such as the amplitudes of particular evoked potentials of particular rhythms like sensorimotor rhythms or the firing rates of individual cortical neurons or they can be even more complex measures like spectral coherences. To provide effective BCI performance, the feature-extraction component of the signal processing stage needs to focus on features that encode the relevant output and needs to extract those particular features accurately.
The second phase of BCI signal processing is the translation of signals features into device commands using a translation algorithm. Certain brain signal characteristics such as rhythm amplitudes or neuronal firing rates are translated into commands that specify outputs, such as letter selection, cursor movement, or prosthesis operation. Translation algorithms can be simple or complex like neural networks or support vector machines.
Benefits of BCI technologies
Allowing a form of interaction between a human and a machine via messages or voice command, BCI applications have many possible uses ranging from simple to unlimited clinical use. These include systems for answering “yes” or “no” to questions, managing basic control of the user’s environment like lights and temperature, controlling a television or opening and closing a hand orthotic. The functions of these systems include basic word processing, sending emails, accessing the internet, or operating a motorised wheelchair.
Fig. 1: Image Of A Mind controlled Wheelchair
BCI applications might enable people who are almost totally paralysedto have a higher quality of life that can also be productive. According to researchers, with proper supportive care and the capability for basic communication,severely paralysed patients can have what they regard to be a reasonable quality of life.Nowadays people who are severely disabled use BCI systems for important purposes in their daily lives. BCI technologies might also support more complex applications such as the operation of a robotic arm or a neuroprosthetic limb that provides multi-dimensional movement.
Fig. 2: Image Of BCI Paralysis Type Accurately
BCI technologies may turn out to be boon for people for whom conventional assistive communication methods are not effective, because severe motor disabilities will preclude their use of voluntary muscle control on which conventional methods depend. Those most likely to benefit include people who decide to accept artificial ventilation to prolong life as the disease progresses, children and adults with severe cerebral palsy who do not have useful muscle control, patients with brainstem strokes who have only minimal eye movement control, individuals with severe muscular dystrophies or peripheral neuropathies, and possibly people with acute disorders causing extensive paralysis. BCI technology may come handy for patients with high cervical spinal cord injuries, as conventional assistive communication methods require use of their remaining voluntary muscle control.
A success story
Researchers at Wadsworth’s National Center for Adaptive Neurotechnologies (NCAN), have developed a BCI system that helps paralyzed people to communicate. The Wadsworth BCI system, created by Dr Jonathan R. Wolpaw, records the brain’s electrical activity using electrodes attached to a cap worn by the user who can perform various functions such as word processing, write e-mails, select computer icons, or move a robotic arm.
Fig. 3: Representational Image Of Management Plastic Arm With Help Of Thought
The Wadsworth BCI enabled Scott Mackler, a neuroscientist at the University of Pennsylvania with late-stage ALS, to continue his research. Earlier, he couldn’t work independently without it, but later he could type with his brain waves with the system allowinghim to choose from a matrix of letters, numbers, and function codes.NCAN has now embarked uponresearch on rehabilitation of movement after stroke and spinal cord injury.
Need for balance
The more complex the contribution made by machines, the more important is to have efficient communication between them and users. Hence the question arises – Does the technology enable the machine to exactly understand the command as it is meant? If not, then there is alwaysa risk of misunderstanding makingthe system often not work as it should.
It can be said that BCI technology still has a long way in presenting an adequate replacement of the existing technologies for communication and control in patients with a minimum of preserved motor and cognitive function. Rehabilitation in neurological disease and injury seems to be the area which provides the most immediate measure of benefit to a user but this is typically performed in a clinical environment operated by clinically trained persons.
Therefore, the user must be taken into account in the development of interfaces and sensors for such devices. The systems and devices need to be intuitive and must not place excessive demands on the user. Operating a machine must not be too complex that requires too much familiarization. An ideal communication between human and machine involves the shortest possible response time between command and action. If the response is not forthcoming, users may not perceive the interaction as being helpful, especially in case of neurological diseases and injuries.
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