Calgary Herald

‘Mini strokes’ do lasting damage

Brain injury not detected in normal scans


Although “mini strokes” are thought to be short-lived — symptoms may only last a few hours — new Canadian-led research suggests the damage to the brain could be long-lasting.

Scientists at UBC’s Brain Research Centre are using deep-brain stimulatio­n to peer into the brains of people who have experience­d temporary numbness or vision changes — and finding far more damage than previously thought.

The research suggests mini-strokes, formally referred to as transient ischemic attacks (TIAs), are anything but. An episode of sudden numbness, vision loss or difficulty speaking, a TIA’s symptoms disappear within 24 hours.

But in a study published Thursday in Stroke — the journal of the American Heart Associatio­n — neuroscien­tist Lara Boyd and her colleagues revealed that people who suffer TIAs suffer lasting damage to their brains not detected by convention­al brain scans.

“The assumption has been made that these attacks are temporary and, because the overt symptoms go away, that there is no lasting damage,” said Boyd, noting that when you do an MRI, “more often than not,” you don’t see anything.

Boyd and her colleagues used transcrani­al magnetic stimulatio­n — a device used to help heal the brains of stroke victims with pulses of energy — to create patterns of excitation that exposed the damaged areas deep within the brains of 13 patients who had experience­d a TIA sometime within the previous 30 days.

The researcher­s then compared the responses from the affected side of the brain with those from the unaffected side.

“It is much harder to elicit a response from the affected side of the brain and that is a hallmark of brain damage,” Boyd explained.

“It’s eerily similar to what you see after an actual stroke.”

The researcher­s believe the effects of a TIA are not transient at all. “We aren’t sure if the brain ever recovers,” said Boyd.

People who suffer a TIA are also at much higher risk of stroke within 30 to 60 days of their episode, and those with the most damage, as measured by the asymmetric responses of their brain hemisphere­s, are likely at highest risk.

The researcher­s hope to use their technique to identify patients with the most damage from such ministroke­s in order to begin aggressive treatment in the hopes of heading off a major stroke.

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