An astonishingly simple, easy-to-do intervention may help stroke victims — perhaps even slowing or stopping the resulting destruction of brain tissue that causes disability. What is it? Gentle stroking, light touch, soft music or other forms of sensory stimulation… it’s really that basic!

This intriguing discovery involved tickling the whiskers of rats while they were having strokes, and it falls into the “really surprising” category because the benefit was far more dramatic than what researchers expected.

Here’s the backstory: At the University of California-Irvine, scientists studying the brain’s self-repair mechanism (plasticity) induced stroke in rats to test the effect of sensory stimulation. The researchers tied off a brain artery in a rat to bring on a stroke and then tickled its whiskers. To the researchers’ amazement, this ended up preventing the stroke altogether! How? Imaging revealed that the sensory stimulation provided by stroking the whisker prompted the blocked blood to find new pathwaysinto the cerebral cortex, the part of the brain affected by the stroke.

Tickling Boosts Blood Flow

While it’s true that the normal, healthy brain responds to an external signal with increased blood flow, the researchers never anticipated that this would happen when the sole source of blood was cut off at the base of the artery, I was told by study coauthor Melissa Davis, BS — she and the other author, Chris Lay, BS, are graduate student researchers in the department of neurobiology and behavior. But that’s exactly what tickling the rats’ whiskers accomplished. Some of the nearby arteries simply expanded to accommodate additional blood, while others rerouted blood via collateral vessels (tiny stems of blood vessels that are fused together, present in both rats and humans). Sometimes the blood even flowed backward from the blockage to reach important parts of the brain through a different route!

There are some caveats: This worked only when the whiskers were tickled within an hour or two of the onset of the stroke — if more than three hours had passed since the stroke began, it actually made the stroke worse. This time limit is consistent with what happens when strokes in people are treated with tPA (tissue plasminogen activator), Davis pointed out. And it’s not yet known whether this sort of stimulation would be safe for a person who has had a hemorrhagic stroke (caused by a broken blood vessel in the brain rather than a blockage, which accounts for about 15% of all strokes) since it might increase bleeding or have another as yet unknown neurological effect.

How Does This Help?

How might this finding help men and women who have strokes? Davis pointed out that early stroke symptoms generally provide information about the part of the brain that is being affected — whether the visual center, auditory or motor control. So if a person has suffered a stroke in the auditory cortex (where sound is recognized), it may be that playing music will bring more blood to that part of the brain, possibly rescuing it from blood deprivation and potential damage. This is as yet theoretical, but the research team is already studying the practical applications. The day may not be far off when instead of keeping a stroke patient quiet, as is currently the standard practice, health-care professionals will instead lightly pat the person’s hands and face… sing… play cartoons… or provide other forms of sensory stimulation to keep fresh blood flowing in the victim’s brain.