bleedingstrokeStem cell injections into the brain may improve some cognitive functions in people who haven’t recovered months or years after a clot-caused stroke, according to a study presented at the American Stroke Association’s International Stroke Conference 2015.

In a preliminary study, 18 patients who had sustained moderate or severe ischemic strokes and remained paralyzed on one side six to 60 months later (average 22 months) received stem cell injections. Patients received 2.5, 5 or 10 million adult bone marrow cells engineered to secrete factors previously shown to protect neurons in animal models.

In tests performed six and 12 months after the injections, some patients showed improvement in some verbal learning tasks. Results differed depending on the location of the stroke. These results should prompt further investigations of cognitive function in studies of stem cell therapy for stroke recovery, researchers said.