The worldwide pandemic of COVID-19 has elevated our awareness of health conditions that can make us vulnerable. Stroke is definitely one of them. In the Journal of Neurology, Neurosurgery & Psychiatry, a case series reported that COVID-19 may cause ischemic stroke in younger adults who have severe reactions to the virus. For those who have survived a stroke, recovery can be daunting and residual impairments impact the simplest of tasks. Daily lives are disrupted not only for the stroke survivors but for caregivers as well. Recognizing that there are unique circumstances for stroke survivors and caregivers, the American Stroke Association is hosting a four-part podcast series titled Stroke and COVID-19.
Even in the best of times, surviving the aftermath of a stroke can be a struggle. Depending on several factors, residual effects vary like impaired speech or vision, cognitive impacts and physical deficits like drop foot syndrome or hemiplegia. Rehabilitation plays an important role in stroke recovery along with diagnostics and adaptive technology. This month we will focus on the established and new neurotechnologies that can be of aid.
A stroke occurs when the blood supply to part of the brain is suddenly interrupted or when a blood vessel in the brain bursts, spilling blood into the spaces surrounding brain cells. Brain cells die when they no longer receive oxygen and nutrients from the blood or there is sudden bleeding into or around the brain. The symptoms of a stroke include sudden numbness or weakness, especially on one side of the body; sudden confusion or trouble speaking or understanding speech; sudden trouble seeing in one or both eyes; trouble with walking, dizziness, or loss of balance and coordination; or sudden severe headache with no known cause. There are two forms of stroke: ischemic — blockage of a blood vessel supplying the brain, and hemorrhagic — bleeding into or around the brain.
Ischemic strokes, the most common type of strokes, can be treated with a drug called t-PA that dissolves blood clots obstructing blood flow to the brain. The window of opportunity to start treatments is three hours; however, allotting time for evaluation, patients need to get to the hospital within 60 minutes.
A study published in The Lancet Neurology and funded by the Bill & Melinda Gates Foundation reported that stroke is the second largest cause of death globally. There are 795,000 occurrences of stroke in the U.S. each year and approximately 7 million Americans are currently living with the effects of stroke, according to the American Heart Association. Approximately one-third of all strokes result in severe impairments; another one-third of cases result in moderate impairments. In addition, nearly 20 percent of stroke survivors develop some form of cognitive disability, often language-related.
Stroke is also the leading cause of epilepsy among older adults. More than one in 10 people who suffer from a stroke develop epilepsy, and having a stroke at a younger age appears to increase the risk. The greater the damage caused by the stroke, the more likely the development of post-stroke epilepsy. Brain damage from a stroke tends to be more extensive in younger people so they are at higher risk for developing PSE.
The economic burden of stroke has been estimated at $34 billion per year in the U.S., which includes $17 billion in hospital, physician, and rehabilitation expenses, and $13 billion in indirect costs such as lost productivity including the caregiver. The average cost per patient within the first 90 days after a stroke is $15,000 in the U.S.
Neurotechnology devices have applications both in the diagnostic assessment and in therapeutic applications to rehabilitate stroke survivors so they can recover lost functionality, as well as adaptive prosthetics to aid in daily functions. Diagnostics and brain assessment applications can help to understand the region of the brain that was damaged from the stroke and potentially aid the design of a treatment pathway. Many of these application use electroencephalogram(EEG) for diagnosis as well as brain monitoring to map the progress of rehabilitation including cognitive training and monitoring for potential seizures.
There are a variety of rehabilitation tools such as robotics, muscle stimulation and brain stimulation. Many people who have survived a stroke have some form of paralysis in the arms, hands, legs and feet. Robotic rehabilitation systems are an important tool during early recovery of arm and hand function. They can also aid in the recovery of standing and walking. Surface stimulation and sensing devices can be used in the rehabilitation of upper and lower extremities. Available mostly for arm and shoulder recovery, these systems use neuromuscular electrical stimulation to induce movement coupled with electromyography (EMG) sensors to detect voluntary muscle movement. Other rehabilitation categories include, vibration, cognitive gaming, vision restoration exercises and muscle stimulation cycling. Some systems are commercially available in stroke rehabilitations centers, independent neuro-gym facilities and some home-based therapy.
In the case when voluntary recovery has slowed or plateaued, a category of neural prosthetic applications can aid in daily functions such as eating, dressing, or walking. There are also several commercial companies offering external muscle stimulation systems to regain function of the arm and shoulder as well as others focusing on stimulation of the foot to overcome drop foot syndrome, a common condition of stroke survivors. Some stroke survivors have impairments in swallowing and breathing. Surface, minimally invasive and implanted neurotechnology systems can provide daily assistance to help avoid a feeding tube or the use of a ventilator. These systems can be used as a prosthesis or as a rehabilitation tool depending on the function of the end-user.
Brain stimulation along with exercises or rehabilitation techniques are currently under clinical trial investigation. Some stimulation devices are available commercially. Transcranial Magnetic Stimulation (TMS) is a treatment using magnetic stimulation of brain structures and networks impacted by the stroke. This can be coupled with range of motion or rehabilitation exercises to help regain function. Transcranial direct current stimulation (tDCS) is an emerging brain stimulation technique that can be applied with traditional stroke rehabilitation techniques. These brain stimulation modalities are commercially available but has yet to be meet the scientific rigor to be clinically adopted as a specific rehabilitation aid.
To this end there are several neurotechnology applications that are in various stages of clinical investigation. Below is a highlight of a some of these efforts with exciting potential:
MicroTransponder is a company that is exploring the use of vagus nerve stimulation coupled with compensatory upper extremity rehabilitation exercises. The focus is to regain voluntary function in the hands and arms of stroke survivors. The Vivistim system is an implanted device used with synchronized stimulation to the vagus nerve in order to induce neural plasticity in the brain during the rehabilitation process.
Several research institutions and clinical facilities in the U.S. and Europe are investigating the use of transcranial magnetic stimulation as a possible form of stroke rehabilitation. Several research institutions are investigating the use of transcranial magnetic stimulation to induce responses inspecific regions of the brain coupled with rehabilitation techniques such as robotic/virtual-reality training systems that use a hand exoskeleton and a library of therapeutic video games. Brain and muscle interaction are mapped during various normal reaching and grasping activities with physical objects and tasks in virtual video environments.
NeuroDevice Group is a European company that is developing a home-based therapeutic device to treat aphasia, a common communication condition among stroke survivors. Their non-invasive device uses transcranial electrical stimulation of the brain used with speech exercises to improve articulation, fluency and intonation.
In 2019, the study results investigating the use of repetitive upper limb sensory stimulation of the hand was released. Called the PULSE-I study, investigators in the UK recruited 40 stroke survivors with upper extremity arm impairments for a single-blinded, stratified, randomized controlled feasibility study. Participants either received RSS with usual care or simply received usual care over a 2 week period. The results revealed that RSS may improved arm function by tapping into the body’s sensorimotor recovery system immediately following the acute phase of recovery.
Research developments published in 2019 may change the course of stroke rehabilitation. Neurotechnology-based therapies, including brain-machine interfaces, robotics, and brain stimulation, will lead to the largest treatment effects and success if they are tailored to the needs of individual patients, and used in combination, says the authors from the Wyss Center for Bio and Neuroengineering, EPFL, Scuola Superiore Sant’Anna, University of Geneva Faculty of Medicine, and Clinique Romande de Réadaptation. The paper, published in the journal Brain, calls for longitudinal clinical studies to show the rehabilitation benefits of individual therapies as well as the use of multiple complementary therapies used in combination over long time periods.
These are just a few examples of the recent efforts to development neurotechnologies to improve the quality of life for those who have survived a stroke. There are varied technologies for assessment, treatment and rehabilitation. Neurotech Network offers free resources and a directory of devices specifically for Stroke. Check out our Stroke resource page here.
The content for this article was provided by Neurotech Network. The source of references include the World Health Organization, American Stroke Association, the Journal of Neurology, Neurosurgery & Psychiatry and Lancet Neurology.
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