“Gait-freezing” is a common symptom of advanced Parkinson’s disease. It occurs when foot movement pauses while the upper body keeps moving. The pause can be for just a few seconds or several minutes. Researchers have discovered that intentional foot movement — when a patient consciously looks at and steps over a mark or object on the ground — is not affected by gait-freezing as the movement is controlled by a different region of the brain. Last year we wrote about work at the University of Twente with laser-pointers on shoes to guide steps when Parkinson’s patients focus on the light.

Bioengineering students at Rice University have developed a smartphone app that guides Parkinson’s patients with when they gait-freeze by using augmented reality (AR). Based on the same concept as U Twente’s laser-pointer shoes, the Rice smartphone app employs visual cues to prompt the patient to take the next step. When the patient’s gait freezes, they point the phone at the floor or ground, and the app places the image of a block, circle, or some other object where the next step should land. In addition to the visual cue, the app can also trigger a sound or vibration, combining vision, hearing, and touch to guide the person to the next step. To help patients with hand tremors, the students also designed a lanyard case to make the phone easier to handle.

The greatest advantage of the Rice students’ app is its low cost. Other devices on the market based on the same principle range from $200 to $3,000, according to Jeremy David, one of the students involved with the project. In a world where many people look at smartphones while they walk, the AR app has the added advantage of being discrete in that it is less noticeable than someone walking with laser-pointing shoes or cane.