A New Take on Two Effects of Stroke
Date: June 1, 2009
It’s one thing to survive a stroke. Recovering afterwards is another matter.
To improve the odds that patients can emerge from stroke with both mind and body intact, neurologists Argye Hillis and Rebecca Gottesman have been focusing on two sometimes subtle indicators and/or consequences of stroke: aphasia and hemispatial neglect. Though the two disorders have vastly different manifestations—aphasia affects written and verbal language cognition, while hemispatial neglect “erases” visual fields on one side of the body—what they share is the potential to severely affect a stroke patient’s quality of life.
Hillis, who was a speech pathologist before becoming a neurologist, says aphasia is an acquired language impairment due to some kind of neurologic brain damage. Most commonly caused by stroke, aphasia short-circuits the brain’s language center, leaving some people painfully aware that they can’t find the correct words to express their thoughts (Broca’s aphasia). Others, with Wernicke’s aphasia, have no grasp of their cognitive difficulties. “They think they’ve asked you to bring them some coffee,” says Hillis, “when they actually said bring me a pillow.”
Hemispatial neglect is no less confounding. “Some people with right hemisphere stroke tend to ignore things on their left,” says Hillis. “So they don’t eat food off the left side of their plate, they don’t brush the left side of their hair, they don’t shave the left side of their face. They have absolutely no recognition they’re doing this. You can even say, Look to the left; have you missed anything? And they’ll say, Nope, I think I got everything.”
Hillis and Gottesman see early testing for aphasia and hemispatial neglect as being vital to better overall stroke care. Such tests are generally not part of conventional assessment of stroke risk; physicians instead tend to focus on motor and muscular issues such as slurred speech, partial paralysis and limb weakness. Yet Gottesman notes that the additional testing is quick and easy.
“I found,” she says, “that when you add two simple tests of hemi-spatial neglect, one looking at visual fields, the other crossing out lines on a page—if people are neglecting, they won’t cross out all the lines—you can calculate their error rate and add that to the current NIH stroke scale [a rating of stroke severity]. “I also found that that the combination was a better predictor of the actual stroke volume, as measured by MRI, and functional outcomes than the NIH stroke scale alone.”
Gottesman hopes that such studies will convince the National Institutes of Health to give more weight to cognitive issues when evaluating stroke outcomes.
While both aphasia and hemispatial neglect respond to various forms of language and ocular therapies, and often somewhat resolve as the brain constructs new neural pathways, the most promising treatment is to bring blood flow back to affected areas. This is where neurosurgeon Judy Huang comes in. By testing for aphasia and hemispatial neglect, which can occur from mini-strokes or transient ischemic attacks (TIAs), Hopkins neurologists can bring Huang into the picture before disaster occurs.
“If my colleagues see patients who have symptoms and they’re found to be good candidates for surgery—the source of their TIA is a blockage in a carotid artery—they know to call me and I’ll do a carotid endarterectomy,” says Huang.
The surgery, which scrapes plaques and potential clots from the artery, greatly reduces the chance of a larger stroke occurring, while the suddenly increased blood flow may lessen or alleviate aphasia and hemispatial neglect. “If all goes well,” says Huang, “the patient can go home the next day.”The greatest challenge with the current robot, Richmon explains, is the rigidity of its arms, which makes it difficult to maneuver around the corners and narrow passages between the mouth and the tumor site. To overcome that obstacle, Richmon and his collaborators are developing bendable, snakelike arms as an alternative.
Even without yet having perfected such modifications, Richmon says, “we’ve been able to use the existing robot to reach tumors that otherwise would have required large incisions. Our goal is to come up with even better approaches, and we would like to be one of the first centers that really pushes this to the forefront in the United States."