Goggle Device Helps Distinguish Between Vertigo and Stroke

Co-authors Georgios Mantokoudis, left, and Ali Tehrani demonstrate the video eye-movement device. (Johns Hopkins University)

Medical researchers at Johns Hopkins University in Baltimore, with colleagues at the universities of Illinois and Michigan, tested a device resembling a pair of swim goggles to tell if a patient experiencing severe, continuous dizziness is having a stroke or a more benign condition. The findings of the team led by professor of neurology and otolaryngology David Newman-Toker appear online in the journal Stroke (paid subscription required).

Newman-Toker and colleagues addressed a diagnostic problem facing emergency clinicans when a patient reports a long bout of disabling dizziness, which could be a symptom of a stroke. He estimates that of the 4 million emergency room visits in the U.S. for dizziness or vertigo each year, at least half a million patients are at high risk for stroke. The most common causes for continuous dizziness are benign inner ear conditions, but Newman-Toker says many emergency room doctors find it difficult to tell the difference between the benign conditions and something more serious, such as a stroke.

Normally, clinicans use three eye movement tests that act as a stress test for balance. One of those tests, a horizontal head impulse test, is considered an accurate predictor of stroke. Patients are asked to look at a target on the wall and keep their eyes on the target as doctors move the patients’ heads from side to side.

The test, notes Newman-Toker, requires a specialist to determine if a patient is making the fast corrective eye adjustments that would indicate a benign form of dizziness as opposed to a stroke. The small, portable device in this study makes the same test, but uses video technology to capture minute eye movements that would be difficult even for many physicians to catch.

The device resembles a pair of swim goggles worn by the patient. The goggles are connected to a small video camera and accelerometer that send continuous images of the eye to a laptop computer. The computer has software that interprets eye position based on movements and views of the pupil, while the accelerometer measures the speed of the movement of the head. The system is made by medical device manufacturer GN Otometrics to assess balance, but is as yet not approved for use in the U.S. (The company loaned a device to the team, but was otherwise not involved in the study.)

The researchers enrolled 12 patients at Johns Hopkins University medical center and University of Illinois hospital in Peoria in a proof-of-concept study to test the diagnostic accuracy of the test. The patients all had new cases of persistent dizziness, and the video device diagnosed six of the patients with a stroke and six with a more benign condition, such as vertigo. The patients then underwent MRIs which confirmed the original diagnosis in all 12 cases.

“We’re spending hundreds of millions of dollars a year on expensive stroke work-ups that are unnecessary,” says Newman-Toker, “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.” If the test is confirmed in larger studies, Newman-Toker believes the test could serve the same function as an electrocardiogram to rule out heart attack in patients with chest pain.

Read more:

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• Student Start-Up Company Develops Stroke Rehab App for iPad
• NIH Grant to Fund Translational Research on Blood Clotting

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