March 6, 2013
Simple Portable Device Can Diagnose Stroke With High Accuracy
Brett Smith for redOrbit.com - Your Universe Online
A team of American scientists has developed a new device capable of reading a person´s head and eye movements that can determine if continuous and severe dizziness is being caused by a stroke.
Because it is difficult to quickly diagnose if a person´s dizziness, vomiting and sensations of vertigo are being caused by a stroke, there are about 4 million stroke-related emergency room visits annually in the United States. However, these symptoms can also be associated with a fairly benign inner ear condition. To determine if the cause of these symptoms are in fact signs of a stroke, most doctors choose to rely on brain imaging, an expensive and often inaccurate tool for diagnosing stroke.
"Using this [newly developed] device can directly predict who has had a stroke and who has not," said study coauthor Dr. David Newman-Toker, an associate professor of neurology at the Johns Hopkins University (JHU) School of Medicine. The published paper appears in the journal Stroke.
"We're spending hundreds of millions of dollars a year on expensive stroke work-ups that are unnecessary, and probably missing the chance to save tens of thousands of lives because we aren't properly diagnosing their dizziness or vertigo as stroke symptoms," Newman-Toker said in a statement.
In some cases, specialists have been known to use an extremely accurate bedside clinical test based on examining a patient´s head and eye movements to diagnose a stroke. According to Newman-Toker, in the hands of a capable doctor the test is "nearly perfect, and even better than immediate MRI."
To develop the device, researchers performed the same test using a small, portable device capable of detecting minute eye movements that could be difficult for even the most experienced physicians to notice. An accelerometer on the device measured the patient´s head movements and the device´s software interpreted 12 volunteers´ eye positions based on movements and views of the pupil. After being tested by the device, the test subject underwent MRI scans that would eventually confirm all 12 diagnoses given by the experimental device.
According to the authors, the new device could be used to prevent the misdiagnosis of up to 100,000 strokes a year. The faster and cheaper test could also lead to earlier stroke diagnosis and more efficient triage decisions if patients do make it into a hospital.
The device could help to cut down on the waste that plagues healthcare systems in the developed world. Newman-Toker said head CT scans are ordered for roughly 40 percent of patients who come to the hospital with stroke-like symptoms. However, those scans are often inaccurate — missing more than 80 percent of strokes that occur in the brainstem and cerebellum.
As a side note, Newman-Toker said that MRI is the more definitive test for diagnosing a stroke, although it isn't readily available in some emergency departments. MRI scans also cost around four times the price of a CT scan.
Most importantly, the device could prevent overlooked strokes, which lead to roughly 20,000 to 30,000 preventable deaths or disabilities a year. Newman-Toker said the technology could someday be integrated into a smartphone, which would enable wider access to an accurate stroke diagnosis.