Dizziness is responsible for nearly 3 million emergency room visits every year in the United States. In most of the cases, the dizziness is caused by a benign inner ear problem, or is the result of short-lived discomfort or distress, including anxiety, depression, or certain phobias. However, approximately 4% of patients that present to the emergency room complaining of dizziness are experiencing a stroke or transient ischemic attack. Since more than half of patients with dizziness who are experiencing a stroke show no other symptoms, misdiagnosis is frequent and common. Now, a study published in the journal Stroke reports that a simple one-minute bedside eye exam could be more effective in diagnosing stroke than Magnetic Resonance Imaging (MRI).

“Time is brain” in the treatment of stroke. If a quick and accurate diagnosis is not made, patients can experience serious complications, including permanent disability or death. Typical stroke symptoms include dizziness, one-sided weakness, numbness, and speech problems. The gold standard for stroke diagnosis is an MRI, but these are costly, time-consuming exams, and the wait time may be several hours in some cases, potentially leading to loss of brain function and limiting treatment options. Now, researchers have shown that three simple eye-movement tests are more accurate than an MRI, anyway. The study included 101 patients complaining of severe dizziness; all had at least one risk factor for stroke. More than half presented to the emergency room for treatment, while others were already admitted in the hospital. The eye movement test accurately diagnosed all of the strokes and all but one of the inner-ear conditions, while MRI misdiagnosed 12% of the strokes.

Patients were assessed and evaluated by neuroimaging within 72 hours of the onset of dizziness. The three-step eye exam is known as HINTS (Head-Impulse-Nystagmus-Test-of-Skew) and evaluates (1) the ability of the patient to keep the eyes stable as the head is rotated rapidly side-to-side, (2) the jerkiness of eye movements as the patient follows the doctor’s finger left and right, and (3) the vertical misalignment of the eyes. Patients also underwent an MRI. If the eye movement tests indicated a stroke, but the MRI did not, patients received a follow-up MRI. Overall, the HINTS exam was 100% sensitive and 96% specific for stroke, correctly diagnosing all 69 ischemic strokes and 24 out of 25 inner ear problems among the study population. The initial MRI scan misdiagnosed 8 of the 69 stroke patients, but these were confirmed with repeat scans.

The current study is limited by its small size and restricted population, but the results are promising. While the health care system searches for ways to contain costs but improve quality of care, a quick and easy -– and basically free — eye exam could prove useful in diagnosing stroke victims, especially when costly MRI’s could fail to diagnose stroke in a timely matter. More research is needed before the results of this latest study can be generalized to a larger population, but it is possible that physicians could move back to an age of simple, straightforward bedside diagnosis and stop relying on expensive diagnostic equipment.

References

Newman-Toker, D., & Pronovost, P. (2009). Diagnostic Errors–The Next Frontier for Patient Safety JAMA: The Journal of the American Medical Association, 301 (10), 1060-1062 DOI: 10.1001/jama.2009.249

Kruschinski, C., & Hummers-Pradier, E. (2008). Diagnosing Dizziness in the Emergency and Primary Care Settings Mayo Clinic Proceedings, 83 (11), 1297-1298 DOI: 10.4065/83.11.1297-a

Newman-Toker, D., Kattah, J., Alvernia, J., & Wang, D. (2008). Normal head impulse test differentiates acute cerebellar strokes from vestibular neuritis Neurology, 70 (Iss 24, Part 2), 2378-2385 DOI: 10.1212/01.wnl.0000314685.01433.0d

Kattah, J., Talkad, A., Wang, D., Hsieh, Y., & Newman-Toker, D. (2009). HINTS to Diagnose Stroke in the Acute Vestibular Syndrome. Three-Step Bedside Oculomotor Examination More Sensitive Than Early MRI Diffusion-Weighted Imaging Stroke DOI: 10.1161/STROKEAHA.109.551234