New approaches to increasing human-machine interaction (HMI) have proven extremely useful in mitigating the effects of neurological diseases and injuries. Before we delve into the complexities of these technologies, let's learn how HMI works in simple terms.
Technologies and IT systems are taking on important tasks in our daily lives and work visibly or behind the scenes. It is now well known that smooth communication between people and machines requires interfaces – the place where or the action by which a user interacts with the machine. Using certain sensors and interfaces, these machines can be controlled by mouse, touch screens, voice or gestures. At a more advanced level, virtual reality (VR) glasses allow engineers to walk through planned factory buildings and chatbots to automatically respond to customer requests.
HMI involves interaction and communication of people and automated systems with each other. It has long since stopped being confined to traditional industrial machines, but now concerns computers, systems or digital devices, thanks to the development of the Internet of Things (IoT). In this system, more and more devices are interconnected and automatically carry out tasks.
How HMI is useful in treating neurological diseases
Millions of people experience some type of brain disease during their lifetime. Alzheimer's disease and other neurodegenerative or age-related mental disorders are quite common today. Neuromuscular diseases, such as amyotrophic lateral sclerosis (ALS), make people unable to communicate. ALS causes people to end up losing all ability to use their muscles and communicate through speech, nodding their head or even blinking or looking.
It is urgent to find better ways to prevent and treat brain diseases and understanding how our brain works is important to keep our economies at the forefront of new technologies and information 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 such as neural prostheses are artificial extensions of the body that restore or supplement nervous system function lost during illness or injury. These interfaces are used to allow individuals with disabilities the ability to control their own bodies and lead fuller, more fulfilling lives.
The advent of BCI
Brain-Computer Interface (BCI) is an advanced form of HMI that involves analyzing and translating brain signals into commands that are relayed to output devices that perform desired actions. It has proven to be a very useful tool for providing alternative communication and mobility to patients suffering from nervous system injuries. Furthermore, BCI technology is evolving to provide therapeutic benefits by inducing cortical reorganization through neuronal plasticity. To more efficiently deal with health problems such as ALS, Parkinson's disease, spinal cord injuries, stroke and disorders of consciousness, this technology has proven to be very effective in treating neurological disorders.
BCI can be defined as a direct communication pathway between an enhanced or wired brain and an external device. Targeted to research, map, assist, augment or repair human cognitive or sensorimotor function, BCI has made even complex systems easier to use. These machines are capable of adapting more and more to human habits and needs and with this humans are expanding their scope of experience and field of action.
In 1924, Hans Berge was the first to record the electrical activity of the human brain with the development of electroencephalography (EEG). He analyzed the interrelationship of alternations in EEG wave diagrams with brain diseases. In the 1970s, Professor Jacques Vidal coined the term “BCI” when demonstrating the control of devices based on a single neuron, allowing computers to be a prosthetic extension of the brain.
How does BCI technology work ?
BCI technology is used to record and analyze brain signals to determine the user's desired output; for example, which letter to select to spell a word or to indicate in which direction to move the cursor, and so on. The main purpose of clinical BCI systems is to help patients communicate with their environment or aid in their recovery. BCI can be used to replace, restore, enhance, supplement or enhance the natural output of the Central Neural System (CNS).
This signal processing step has two phases:
The first phase is known as Resource 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 specific evoked potentials of specific rhythms, such as sensorimotor rhythms or the firing rates of individual cortical neurons, or they can be even more complex measures, such as spectral coherences. To provide effective BCI performance, the feature extraction component of the signal processing stage needs to focus on the features that encode the relevant output and needs to extract these specific features accurately.
The second phase of BCI signal processing is the translation of resource signals into device commands using a translation algorithm. Certain characteristics of brain signals, 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, such as neural networks or support vector machines.
Benefits of BCI technologies
Enabling a form of interaction between a human and a machine through messaging or voice command, BCI applications have many possible uses, from simple clinical use to unlimited clinical use. These include systems for answering “yes” or “no” to questions, managing basic control of the user's environment such as lights and temperature, controlling a television, or opening and closing a manual brace. Functions of these systems include basic word processing, sending emails, accessing the internet, or operating a motorized wheelchair.
Fig. 1: Image of a mind-controlled wheelchair
BCI applications can allow people who are almost totally paralyzed to have a higher quality of life that can also be productive. According to researchers, with adequate supportive care and basic communication skills severely paralyzed patients can have what they consider to be a reasonable quality of life . Nowadays people with severe disabilities use BCI systems for important purposes in their daily lives. BCI technologies can also support more complex applications, such as operating a robotic arm or a neuroprosthetic limb that provides multidimensional movement.
Fig. 2: Image of BCI paralysis type accurately
BCI technologies may prove beneficial for people for whom conventional methods of assistive communication are not effective, because severe motor impairments will impede the use of the 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 have no useful muscle control, stroke patients who have minimal control of their eye movements. , individuals with severe muscular dystrophies or peripheral neuropathies, and possibly people with acute disorders causing extensive paralysis. BCI technology may be useful for patients with upper cervical spinal cord injuries, as conventional methods of assistive communication require the use of 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 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, which can perform a variety of functions such as word processing, writing emails, selecting computer icons or move a robotic arm.
Figure 3: Representative Image of Plastic Arm Management with Thought Aid
The Wadsworth BCI allowed Scott Mackler, a neuroscientist at the University of Pennsylvania with late-stage ALS, to continue his research. Previously, he couldn't work independently without it, but later he could type with his brain waves with the system that allowed him to choose from an array of letters, numbers, and function codes. NCAN has now begun research into movement rehabilitation after stroke and spinal cord injury.
Need for balance
The more complex the contribution of machines, the more important efficient communication between them and users will be. Hence the question arises: does the technology allow the machine to understand the command exactly as it is intended? Otherwise, there is always a risk of misunderstandings, meaning that the system often does not work as it should.
It can be said that BCI technology still has a long way to go to present an adequate replacement of existing technologies for communication and control in patients with a minimum of preserved motor and cognitive function. Rehabilitation in neurological diseases and injuries appears to be the area that provides the most immediate measure of benefit to a user, but this is typically carried out in a clinical setting operated by clinically trained people.
Therefore, the user must be taken into consideration when developing interfaces and sensors for such devices. Systems and devices must be intuitive and must not impose excessive demands on the user. Operating a machine should not be too complex and require a lot of familiarization. Ideal communication between man and machine involves the shortest possible response time between command and action. If the response does not occur, users may not perceive the interaction as useful, especially in the case of neurological diseases and injuries.
