Diagnosing a Stroke May Need an Eye Test, Not an MRI

A Johns Hopkins neurologist, Dr Newman-Toker, has made an interesting discovery about diagnosing stroke in people presenting with dizziness.  Many strokes are pretty obvious – paralysis or weakness of one or both limbs on one side of the body, speech difficulty, etc. – but some patients may complain of severe dizziness and little else (at least originally).  Dizziness, of course, is a common medical problem that sends many people to the ER.  Most cases are due to relatively harmless inner-ear balance problems (acute vestibular syndrome), but 4% may be a sign of a stroke or transient ischemic attack (TIA) affecting the vertebrobasilar artery.  People with stroke have altered eye movements that depend on the part of the brain affected, but which are distinct from those seen with inner-ear diseases.  This led Dr Newman-Toker to undertake his study, results of which are published online in the journal Stroke. 

One hundred and one patients with the vestibular syndrome (vertigo, nausea, vomiting, dizziness, gait impairment) with at least one stroke risk factor (high blood pressure, high cholesterol, irregular heart beat) were enrolled.  They underwent eye exams that included: (1) ability to keep eyes stable as head is rotated rapidly to either side, (2) jerking eye movements during tracking a moving finger from left to right & vice versa, and (3) checking eye alignment as horizontal or tilted.  All the patients then had an MRI scan; if their eye tests were suggestive of a stroke but their MRI was negative, they had a second MRI.

Finally, 69 patients were diagnosed with stroke, and 25 with inner-ear conditions (the remainder had other neurological conditions).  The eye movement tests had correctly identified all the stroke victims, and 24 of the 25 with inner-ear conditions.  On the other hand, the MRI scans were initially negative in 8 of the stroke patients, but then correctly diagnosed with the second MRIs.

These findings need to be verified in larger studies, in people with less intense dizziness, etc.  However, if they prove to be reproducible they may lead to the use of a speedy examination to replace the need for an MRI, and an earlier diagnosis of stroke, so that treatment can be started sooner.  So, an important and successful “proof of principle” study, I would say.