Mobility aids such as rollators, walkers, and wheelchairs help those with disabilities navigate the world more easily. But for those who have lost most muscle control, they’re still not enough.

That’s why scientists from Duke University are trying to develop a wheelchair that can be controlled by the user’s thoughts. They’ve tested the concept by implanting two rhesus monkeys with intracranial implants and seating them in robotic wheelchairs. The monkeys soon learned to use their thoughts to navigate the wheelchair around the room in order to reach grapes that the scientists put there as rewards. The more time the monkeys spent using the mind controlled wheelchair, the faster and more efficient they became.

This device could change the lives of those unable to use a joystick or other methods currently used to pilot wheelchairs. The device works by picking up electrical pulses emitted by the brain in the area responsible for movement, and translating these impulses into directional movement of the robotic wheelchair. Though other methods of measuring brain waves, such as EEGs, are less invasive they’re also less precise. The intracranial implant would give users much better control of their chair.

Neurobiologist Miguel Nicolelis said that his team first hopes to “expand the experiment by recording more neuronal signals to continue to increase the accuracy” of the mind controlled wheelchair, and then begin human trials.