While it was a very small study, and it's early days, research from Stanford University suggests that stem cells injected directly into the brain could help patients recover from strokes. Every year, about 800,000 Americans experience a stroke. It's the leading cause of disability and about 130,000 of those who suffer a stroke will die from it. Most of the recovery that a stroke patient experiences will happen in the first six months, so medical professionals have not been hopeful for patients who are still dealing with significant impairments after that point.
The study at Stanford only included 18 patients but all of them experienced significant motor improvement in the first month after having stem cells injected directly into the brain via a small hole drilled into the skull. Researchers believe that the stem cells are reducing inflammation and also secreting chemicals that activate brain cells surrounding the damaged parts of the brain, so those areas can take over function from the circuits in the brain that no longer work. Giving the brain a new level of plasticity essentially makes it function as a younger brain, making new connections. This new level of function can result in recovery from the debilitating effects of a stroke in some patients.