As everyone knows by now, when someone experiences a stroke “time lost is brain lost.” But before treatment can begin, it is critical to confirm that the patient isn’t experiencing stroke-like symptoms from another, less life threatening condition. CT scans are usually performed as soon as possible to diagnose a stroke, but they’re not definitive, while MRI suffers from high cost and the fact that many clinics simply don’t have one available for emergency use. A team from Johns Hopkins Medicine has developed a considerably cheaper solution that so far has performed just as well as MRI exams in identifying stroke in a small pilot study.
Strokes have unique symptoms, some of which can be spotted in eye movements of those afflicted. Yet, visual tests have been very subjective, requiring a physician to detect slight irregularities in the ocular movement. The new system from Hopkins uses special glasses to track the eyeballs while a clinician performs head impulse testing (rotating the patient’s head while he looks at a stationary object). It is to be used specifically in patients presenting with dizziness/vertigo to differentiate between stroke and benign causes of the same symptoms. The researchers dub the technique as “ECG for the eyes,” being a fast and relatively easy parallel to how cardiac events are currently detected.
From the study abstract in Stroke:
Methods—Proof-of-concept study (August 2011 to June 2012). We recruited adult emergency department patients with acute vestibular syndrome defined as new, persistent vertigo/dizziness, nystagmus, and (1) nausea/vomiting, (2) head motion intolerance, or (3) new gait unsteadiness. We recorded eye movements, including quantitative horizontal head impulse testing of vestibulo-ocular-reflex function. Two masked vestibular experts rated vestibular findings, which were compared with final radiographic gold-standard diagnoses. Masked neuroimaging raters determined stroke or no stroke using magnetic resonance imaging of the brain with diffusion-weighted imaging obtained 48 hours to 7 days after symptom onset.
Results—We enrolled 12 consecutive patients who underwent confirmatory magnetic resonance imaging. Mean age was 61 years (range 30–73), and 10 were men. Expert-rated video-oculography–based head impulse test, nystagmus, test-ofskew examination was 100% accurate (6 strokes, 6 peripheral vestibular).
Study abstract in journal Stroke: Quantitative Video-Oculography to Help Diagnose Stroke in Acute Vertigo and Dizziness