Do you remember as little kids when we liked to spin round and round very fast so that when we stopped, we’d stagger around in a state of delicious dizziness? As adults, though, feeling dizzy is not fun. In fact, dizziness is responsible for millions of visits to hospital emergency departments each year. While most cases are likely caused by benign inner-ear balance problems, about 4% are signals of cardiovascular disease such as stroke or Transient Ischemic Attack (TIA – a condition that often warns of impending stroke in the coming days or weeks).
About half of these dizzy patients who are experiencing strokes show none of the classic stroke symptoms like one-sided weakness, numbness or speech problems. In fact, some estimates put the number of misdiagnoses as high as one-third, losing the chance for quick and effective stroke treatment.
Just as the rule for getting immediate help during a heart attack is: Time is muscle” – in stroke circles, doctors say: “Time is brain”.
“We know that time is brain, so when patients having a stroke are misdiagnosed and sent home by mistake, the consequences can be really serious, including death or permanent disability,” says neurologist Dr. Jorge C. Kattah at OSF St. Francis Medical Center, who co-led a recent Johns Hopkins study on eye movement tests to diagnose strokes.
The study of eye movement tests was suggested by previous research showing that people experiencing a stroke have eye-movement alterations that correlate with stroke damage to various brain areas. These changes are distinct from eye-movement alterations seen with benign ear diseases.
Some patients, for example, can’t immediately adjust their eye position if their heads are quickly turned to the side, or they experience jerky eye movements as they try to focus on a doctor’s finger when looking to either side.
Researchers wondered whether testing eye movements in dizzy patients might help them sort out which ones were having a stroke from those with other problems. They found that three simple eye tests were often more accurate in diagnosing strokes than the more commonly used but expensive MRI test.