More than 750,000 Americans experience stroke per year, figures from the U.S. Centers for Disease Control and Prevention (CDC) show.

Although many manage to survive, survivors often end up losing motor function and can no longer walk. Results of a new trial, however, offer stroke patients facing serious long-term disability hope for recovery.

In the new study published in the journal Stroke on June 2, Gary Steinberg, from Stanford University School of Medicine, and colleagues injected adult stem cells into the brains of 18 stroke patients with significant motor deficits for at least six months.

Doctors drilled a small hole through the patient's' skull, through which neurosurgeons injected modified stem cells directly into the areas of the brain near the site of the stroke.

Although the study is still in its early stages, the results were promising. There appears to be no blood abnormalities or other significant side effects after the treatment.

The experimental stem cell test also had speedy effect. The participants experienced significant motor control recovery within the month of the procedure.

The treatment did not only improve the participants' speech and arm movements. Patients who have been relying on the wheelchair for a long time even managed to walk again.

"After injecting stem cells directly into the brain of chronic stroke patients, we were blown away," Steinberg said. "Within days some were lifting their arms over their head. Lifting their legs off their bed. Walking, when they hadn't in months or years. The results were very exciting."

The mobility of the patients improved in the first three months, and these gains were maintained after one year. The improvements were also independent of the age of the patients or the severity of their condition at the start of the trial.

"We see that patients' recovery is sustained for greater than one year and, in some cases now, more than two years," Steinberg said. "Older people tend not to respond to treatment as well, but here we see 70-year-olds recovering substantially."

It is believed that the brain does not recover once it is injured, but the researchers were able to jump-start the damaged brain circuits, and this could potentially revolutionize concepts of what happens after a stroke, traumatic brain injury and neurodegenerative disorders.