Editors' ChoiceStroke

Something to Smile About in Stroke?

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Science Translational Medicine  02 Apr 2014:
Vol. 6, Issue 230, pp. 230ec61
DOI: 10.1126/scitranslmed.3009043

Sudden facial drooping or an uneven smile often indicates the onset of an acute ischemic stroke. Researchers are now investigating using the same neurons that allow us to smile as a new emergency treatment for stroke. Their approach is based on a documented increase in brain blood flow caused by dilation of cerebral arteries after electrical stimulation of autonomic branches of the facial nerve.

To test this approach, Borsody et al. used a noninvasive magnetic stimulator in a canine model of acute stroke involving blockade of a major cerebral artery. Their goal was to reduce the size of the stroke by dilating blood vessels, providing collateral blood flow to the affected area. Thirty min after stroke onset, the investigators applied 5 min of magnetic stimulation to the geniculate ganglion region of the facial nerve on the affected side. Brain blood flow and cell metabolism were then measured by using contrast magnetic resonance imaging and spectroscopy. The researchers also evaluated the safety of this approach in a canine model of brain hemorrhage. The investigators compared facial nerve stimulation with a sham control and found that with stimulation, there was increased brain blood flow for up to 90 min in the area affected by the stroke. The amount of brain tissue injured by the stroke also decreased. In addition, magnetic stimulation preserved brain cell metabolism and was not associated with increased bleeding.

These exciting new results are tempered by the knowledge that extensive collateral blood flow is already present in their canine model, and the study lacks important functional neurological outcome measures. Nonetheless, the investigators have begun to translate their approach by creating a prototype for testing in humans. Perhaps one day soon, smiling can be used not only to diagnose but also to fight back against the devastating consequences of ischemic stroke.

M. K. Borsody et al., Effects of noninvasive facial nerve stimulation in the dog middle cerebral artery occlusion model of ischemic stroke. Stroke 45, 1102–1107 (2014). [Abstract]

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