In 2018, Tomek Finn took his father Nigel to see a physiotherapist. Nigel suffered from vascular dementia, which can present with symptoms similar to Parkinson’s disease, a progressive neurological disorder characterized by motor symptoms such as tremor, stiffness and problems with balance. He lost the ability to walk.
The physical therapist told Finn about cue markers – colored lines on the floor that can lend a hand Parkinson’s patients overcome walking difficulties. Finn wasn’t convinced. He didn’t understand how a few lines on the floor could lend a hand his father. But when they got home, he set up some colorful exercise bands in the kitchen and watched in amazement as his dad easily marched back and forth on them.
This technique, called external cues, involves using visual, auditory or tactile cues – colored tape on the ground, playing a metronome or physical vibrations – to engage neural pathways not involved in the disease. “It can help people focus and take the first step and overcome freezing,” says Claire Bale, deputy director of research at Parkinson’s UK, a British research and support charity.
Although Finn – who worked in London in marketing and video production – was impressed with the effectiveness of this plain intervention, he found it too plain to be actually helpful. However, augmented reality glasses like Magic Leap were just starting to hit the market, so David wondered if they would be able to project virtual lines on the ground to act as clues. To try to make this vision a reality, he founded the startup Strolll.
According to Jorgen Ellis, two years later Strolll had no staff and had about £50 in the bank. Ellis, a Novel Zealander with experience in furniture start-ups, came to the UK looking for his next venture and wanted to get involved in something he was passionate about. His grandfather had suffered from Parkinson’s disease for over a decade, and when he met Finn through mutual contact, he immediately saw the potential of this technology. He joined the team as CEO and started by trying to demonstrate that AR-based guidance was scientifically sound.
Ellis and Finn soon found a group of scientists at VU University in Amsterdam, led by Melvyn Roerdink, who were working on something similar. Stroll acquired their intellectual property and, with Roerdink on board as chief innovation officer, began developing and testing the technology, now called Reality DTx.
Instead of physical wristbands like Finn, Strollla’s AR software simulates colored lines on the floor in front of the user, with each line disappearing as they are removed. A clinical trial (supported by Stroll) confirmed that the signaling technology was feasible and showed promising results.
It can also lend a hand with rehabilitation exercises amid a shortage of physical therapists: the software includes AR games like whack-a-mole and basketball, but designed with functional movements in mind to lend a hand people with Parkinson’s disease. Mark Ross, who was diagnosed with Parkinson’s disease eight years ago at the age of 36 and is now Stroll’s head of brand and artistic strategy, says the games can lend a hand overcome apathy and depression, which are also symptoms of the disease. “You may know you need to exercise… but it won’t help you get out of your chair,” she says. So the fact that it’s a game makes doing the exercises that much more appealing.
The Magic Leap headset that runs the software costs around £3,000 ($3,800), and Stroll charges more than £300 a month for his services – but Ellis says it’s more cost-effective than 30 half-hour live physiotherapy sessions. The company’s ultimate goal is to be “the most widely used rehabilitation software in the world,” Ellis says. They even have a specific timeline in mind: 7 million minutes of rehabilitation with the Stroll device per week by Novel Year’s Eve 2029. Ellis hopes that by then, Strolll could be used to treat all kinds of neurological conditions, from stroke to multiple sclerosis. According to him, there are “almost limitless possibilities.”
The article was published in the January/February 2025 issue WIRED Magazine UK.