April is Parkinson’s Disease Awareness Month, and a group of engineering students at Rice University have announced the creation of an iPhone app designed to keep Parkinson’s patients moving.

Specifically, the app targets a common Parkinson’s symptom known as “freezing.” It happens when people with Parkinson’s are walking: Though their brains are signaling their legs to move, the legs don’t respond, causing people to be stuck in place temporarily.

In those cases, audio or visual cues, such as a light projected slightly ahead of the person’s position, can help to stimulate the body to start walking again.

The most common assistive technology device currently is a walking cane with an attachment that produces a laser line in front of the walker every time the cane contacts the ground. The laser cue encourages the person to take the next step.

But the laser lines can be difficult to see outdoors. And audio cues, such as beeping to encourage movement, can be disruptive because the sound volume can’t always be adjusted.

The phone app created by Rice University students projects a picture of a circle or other object onto the ground to encourage its user to take another step. The app can also provide auditory cues, or can give a vibrating cue.

This system takes advantage of the fact that so many people have smartphones, and that they’re easily portable. Rice students also created a lanyard to hold the phone, for Parkinson’s patients who have difficulty holding a phone in their hands. Students wanted a solution that was discreet and that people with Parkinson’s would feel comfortable using in public.

The students worked with the Houston Area Parkinson Society to recruit volunteers to test the app.

Dan Burke, one of the bioengineering students who developed the app, said in a news announcement for the app, “Our goal right now is to prove that the concept of augmented reality can be used in a therapeutic context while maintaining the user-friendly nature of smartphones.”

Another bioengineering student involved in the project, Keshav Rao, said, “The patients we’ve talked to are a little on the milder end and are still able to walk, but each one of them has started to see instances of freezing, whether it be just for a few seconds or on the order of minutes. They’ve each talked about the mental gymnastics they go through to be able to move their feet again. They’re very interested in anything that can reduce that burden.”