Sep 3 2012
This article was updated on the 3rd October 2019.
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As the evolution of robotic systems unfolds in the world around us, we are starting to see machines taking over manual tasks that would normally be performed by humans. This is already becoming apparent with the introduction of next generation robots as a trial method for assisting with the rehabilitation of stroke patients.
The pathophysiology behind a stroke begins with an interruption of the blood supply to the brain, due to a blood clot in the vessels channeling oxygenated blood to the brain. This, in turn, results in a state of ischemia and damage to the brain tissue.
Some typical signs of stroke can be a sudden weakness or numbness of the face, arm or leg and typically manifests unilaterally – at one side of the body. In addition to limb function impairments, the sufferer can also experience dizziness, headaches, and confusion, and, unfortunately, in severe cases – the occurrence of a stroke can be fatal.
In the UK, there are estimated to be over 1,000,000 patients who have suffered from a stroke, with over 50% being left with a disability that affects their day-to-day activities. Statistics show that approximately one third of sufferers are over the age of 65 years. Meanwhile, over a third of first time strokes happen in middle-aged adults, between the ages of 40 and 69. This disease, along with its rehabilitation, costs the UK healthcare system over £8.2 billion annually.
According to an updated report on Heart Disease and Stroke Statistics—2018 by the American Heart Association, in the United States for 2014, the direct and indirect cost of strokes was estimated to be $40.1 billion, which included costs for physicians, medicine and carers. According to the same report, by the year 2035, the total direct medical stroke-related costs are estimated to more than double, rising to $94.3 billion.
The statistics on the prevalence of strokes are shocking and despite traditional methods to rehabilitate the victims (including treatments such as speech therapy and physiotherapy to name a few), some patients still need a full-time carer in extreme cases. Such intrusive care can often be detrimental for the independence and the feelings of self-worth of stroke survivors.
So why not let a robot help in the rehabilitation process? For most people, it is easy and natural to think about a voluntary action, such as moving a limb to reach an object, but this can be a challenging process for a stroke patient due to the neuronal nature of the injury. Researchers at Rice University, University of Houston, and TIRR Memorial Hermann have developed a brain–machine interface system connected to a robot with the aim of helping with the rehabilitation of stroke patients’ upper limbs.
It is fascinating to think that an interface system could interpret a patient’s thoughts into action using an exoskeleton. The exoskeleton is designed to be wrapped around the patient’s arm and covers the patient from the fingers to the elbow. The following video demonstrates how a patient uses Myomo, a personal robotic device, to regain mobility in their arm.
After Stroke | Robot Therapy | Post Stroke Arm Recovery
When it comes to rehabilitation related to nervous system impairments in stroke patients, repetition of actions, movements and tasks have a key role. It is exactly through repetition that patients retain and regain control over the function of their body, therefore enhancing the damaged neuronal signaling transmissions in the brain. It is important to remember that patients have to be internally motivated to initiate a movement in order to be able to work successfully hand-in-hand with the robotic interface system. This is going to be one of the major challenges for seeing satisfactory results from the application of this new rehabilitation project.
The robotic interface system uses Electroencephalography (EEG) that translates and feeds brain wave activity from the stroke patient into electric signals for the MAHI-EXO II robot. The robot is designed to have five degrees-of-freedom providing elbow and wrist flexion-extension (a position made possible when the joint angle to a limb decreases), pronation-supination (rotation of the forearm), and radial-ulnar deviation (physiological movement of the wrist).
The device also has an increased torque output for the forearms and elbow joints in addition to a passive degree-of-freedom to give flexibility in shoulder abduction therapy. This gives the patient a greater freedom of movement of the upper body. The design is currently tested in clinical trials with patients who have suffered from a stroke or spinal cord injury.
During the clinical trial phase for this interface system, it is expected that the exoskeleton will help practice repetitive movement of limbs to retrain the brain in regaining control and strengthening the sensory pathway for upper limb movement.
A traditional rehabilitation program involves a carer assisting the patient with their movements. In comparison, the neural interface system with an exoskeleton is more promising as it directly interacts with the patient’s brain waves and further anticipates the movement of the patient’s limbs – technology that could fully engage the patient during therapy.
What Feedback will the EEG Technology Provide about the Patient’s Brain Activity and Recovery?
The purpose of using an EEG interface system is that it allows for a real-time recording to reflect the patient’s brain activity and function (i.e., showing a graphical representation of the plasticity in neural networks as a consequence of repetitive motion techniques due to intervention by the exoskeleton robot).
This robotic assistant is one of few demonstrations of how combining robot technology with additional treatments has the potential to be a common practice in the rehabilitation of stroke patients.
One of the most popular projects that are related to the brain–machine interface systems for the purpose of rehabilitating patients with spinal cord injury is the BrainGate systems. BrainGate involves placing a sensor in the area of the patient’s brain responsible for controlling limb movement. The project, which was researched by Prof John Donoghue at Brown University, has gained popularity in the media for its use on a patient suffering from Locked-in Syndrome. With the use of the brain-machine interface system, the patient was able to use a neural interface system to control a robotic arm that helped bring a flask of coffee to her mouth.
The research on neural interface systems integrated with robots is fascinating and offers a promising approach to delivering care for stroke patients. Yet, such systems need to be fine-tuned to ensure the most efficacious and safe application of exoskeletons.