In a first, doctors say electrodes implanted in the brain of a 13-year-old with severe autism alleviated the boy’s behaviors and allowed him to speak for the first time.

The approach has only been tested on one person, but the German research team that treated the boy said the results reported this month in the journal Frontiers in Human Neuroscience could lead to a better understanding of what’s going on in the brains of those with autism.

Prior to receiving the experimental treatment, the boy who is now 14 and is diagnosed with autism and intellectual disability, engaged in serious, life-threatening self-injurious behaviors, researchers said.

Despite trying various medications, he was nonverbal, unable to interact socially with anyone other than his parents and brother, could not make eye contact and did not sleep more than an hour-and-a-half at a time before waking up to scream, the study indicates. So harmful were the boy’s behaviors that near-permanent restraints were employed to keep him from injuring himself.

Doctors at the University of Cologne in Germany report that they implanted electrodes deep in the boy’s brain, ultimately finding success by stimulating the amygdala area, which is known to affect memory and emotion.

Following the treatment, the boy’s parents reported that his behaviors decreased in frequency and severity, he was able to sleep better and he began enjoying activities like car rides and trying new foods which were previously impossible. What’s more, after six months the boy started saying single words like “papa” and “mama” for the first time.

When the stimulation stopped for four weeks because the battery in the device ran out, the symptoms became more severe again before improving when the battery power was renewed.

“For the first time, we demonstrate that (deep brain stimulation) in the latter structure has the potential to markedly reduce (self-injurious behavior), and also to improve features pertinent to the autistic syndrome, such as deficits in social contacts, affect-modulation and speech, fear and anxiety as well as sleep disorders,” the researchers wrote.

Further study is needed to understand exactly how stimulation from the electrodes is affecting the brain, researchers said.