Researchers have developed an app called FAST AI to detect the most common stroke symptoms — facial asymmetry, arm weakness and speech changes — using machine learning algorithms. The preliminary findings will be presented next week at the American Heart Association’s International Stroke Conference.
“Our goal is very simple. We want to detect stroke at baseline,” said Radoslav I. Raychev, the study’s lead author and a vascular neurologist at the University of California, Los Angeles.
The app is not yet ready for public use, and it’s unclear when it will be available or who it will be marketed to.
Ultimately, Raychev said, the goal is to move beyond the app to other devices or platforms.
“When someone is video chatting, or when they’re talking to ‘a virtual assistant like Alexa,’ or when they’re driving their autonomous driving vehicle, we want to be able to have that passive monitoring to capture the patient’s symptoms if the stroke happens ,” he explained.
Using the app as an educational tool
Neurologists from four major metropolitan stroke centers in Bulgaria tested the app on nearly 270 patients with a confirmed diagnosis of acute stroke.
Using video recordings and device sensors, the app was able to identify facial asymmetry with more than 97 percent accuracy and arm weakness with more than 72 percent accuracy, according to the abstract, which has been peer-reviewed but not yet published in a medical journal.
Since the initial research phase, the app has been tested on hundreds of other patients, Raychev said. It is also designed to detect abnormal speech, but that function has not yet been tested in patients, he said.
Experts said a smartphone app that could help detect stroke symptoms is a great idea. But, they said, the app should be used to educate people about the signs and motivate them to call 911, not as a diagnostic tool.
Some experts were concerned that a false negative result could discourage some people from seeking urgent medical care, for example, which could have devastating consequences.
“This is an exciting and interesting opportunity to see how we can use AI technology to gain more information about stroke symptoms,” said Andrew Russman, chief of the stroke program and medical director of the Cleveland Clinic’s Comprehensive Stroke Center.
“But by no means should this be viewed as a method of deciding whether someone should call 911 or deciding whether someone definitely has stroke symptoms. It is just one piece of information that sounds interesting at the moment, but has no actual application yet.”
Early detection is crucial for strokes
Stroke, which occurs when a blood clot blocks blood flow to the brain or when a vessel in the brain bursts, is the fifth leading cause of death and a leading cause of long-term disability in the United States.
Time is critical in diagnosing the condition and initiating treatment protocols, said Matthew Potts, surgical director of the Comprehensive Stroke Center at Northwestern Memorial Hospital. “When blood is cut off to the brain, neurons die every minute,” he said.
“Clot-busting” drugs can break up clots during the first few hours of an ischemic stroke, which accounts for 87 percent of strokes, preventing or minimizing brain damage.
But these drugs, such as Alteplase IV r-tPA, must be given within 4.5 hours of the onset of an ischemic stroke. In some cases, the clot can be removed during a thrombectomy, a procedure to manually remove it from an artery.
Hemorrhagic stroke may be treated with medications or require surgical intervention.
The prognosis depends on the area of the brain and the amount of tissue affected, but timing is key and, in some cases, quick action can prevent damage, experts say.
Even in transient ischemic attacks, or TIAs, where the blood clot is temporary and does not cause permanent harm, they can be a warning sign that the patient is at risk for future strokes. That’s why stroke patients — and those around them — need to be aware of the symptoms.
More women than men have a stroke, but many don’t realize the risk
Common warning signs of a stroke
The acronym FAST is used to teach people the most common warning signs of a stroke.
- “F” is for droopy face: The face may droop to one side, especially if the person is smiling.
- “A” is for arm weakness: When both arms are raised, one arm may begin to float down.
- “S” is for speech problems: the person may slur words.
- “T” is for time: If anyone experiences any of these symptoms, call an ambulance immediately.
There are also other symptoms, which an app might have a hard time detecting, that can signal a stroke, Russman said. Stroke patients may experience sudden and severe headaches, confusion, loss of vision in one or both eyes, numbness or tingling on one side of their body, or difficulty walking due to dizziness or loss of balance or coordination.
Greg Albers, director of the Stanford Stroke Center at Stanford Medical Center, said stroke symptoms can be disabling.
“The type of vision you lose from a stroke, for example, is usually half your field of view,” he said. “If you’re running into things because you can’t see, waving your hand in front of your eyes, and a lot of vision is missing, that’s very concerning.”
“Symptoms come on very abruptly,” he added.
Other times, however, the symptoms are mild and patients may not take them as seriously and seek medical attention, which could leave them with permanent deficits, experts said.
Albers acknowledged that it can be difficult to determine if someone is having a stroke, which is one reason people should have “a low threshold” for calling 911 when symptoms suggest a stroke.
Even in the emergency room, he said, medical professionals must perform brain scans and other tests before making a definitive diagnosis and starting treatment, because a patient who has a hemorrhagic stroke must be given a blood clot-busting drug — which blocks an artery in the brain. leaking or rupturing – could result in “a disaster”.
“They’re going to bleed more,” he explained.
Experts said the goal of smartphone technology that can detect stroke symptoms should be to get stroke patients to the ER faster.
“We want people to make the mistake of coming to the hospital, not make the mistake of staying home,” said Matthew Fink, chief of neurology at Weill Cornell Medical Center and NewYork-Presbyterian Hospital.
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