Devices: Ninja walker

October 7, 2014 by Thomas Walden Levy

A prototype Demilune walker in its fully extended (left) and quarter-circle (right) configurations.Falling is the leading cause of injury among people over 65. According to the Centers for Disease Control and Prevention, more than 2.3 million senior citizens end up in the emergency room each year. To reduce the toll for those using walking aids, a team of bioengineering undergraduates — Andrea Dickey, Noah Goldman, Geonyoung Kim and Robin Parrish — teamed up in their senior capstone course, taught by bioengineering professor Amy Herr, to design a versatile new walker.


The students talked with patients injured in falls, along with medical clinicians and gerontology specialists like Janice Schwartz, UCSF medical school professor and visiting research scientist at the Jewish Home of San Francisco, who originally presented the problem to the class. The students learned that conventional two-wheeled walkers and four-wheeled rollators are too large and unwieldy for use in narrow hallways and smaller bathrooms. As a result, they are frequently left behind when needed most, leaving elderly users vulnerable to falls.

The team behind the Demilune walker: Geonyoung Kim, Andrea Dickey, Robin Parrish and Noah Goldman. (Photo by Kap Stann)Solution

The team designed a curved two-position walker that is made with conventional materials, like aluminum tubing and plastic wheels, but is unconventional in appearance and operation. Fully extended, its semi-circular shape functions as effectively as a typical rectangular-shaped walker. In its smaller, quarter-circle configuration, the walker’s petite footprint allows it to function more like a rolling cane. Users grasp it with one hand held at their side, rather than in front. This allows them to continue using the walker to safely navigate through tight spaces.


Last spring, the team joined Free Ventures, a student-run startup incubator on campus. Since then, the students have all graduated, formed a company, called Demilune, and have filed for a provisional patent. In July, they received a second place honor in the undergraduate design competition at the Seventh World Congress of Biomechanics.

Their overriding goal is a walker that eases access to cramped hallways and bathrooms, so that the number of older people injured or killed by falls can be greatly reduced. “We hope to give back the elderly their own homes,” says Kim. “It’s very restrictive to have your home be a place that’s difficult or even dangerous to get around in.”