Featuring Sherida Ligtvoet

The Internship

By chance, Sherida Ligtvoet joined Manometric over three months ago. The 23-year-old mechatronics student—a combination of electrical engineering, mechanical engineering, and ICT—was looking for an internship and checked the vacancies posted by companies on the Hague University of Applied Sciences website.

She quickly started working on a project where the Mano-X 3D scanner, already familiar to many hand therapists, acquired an additional function: instantly measuring the position of the joints in the hands to monitor the progress of treatment. This involves measuring the angles of the fingers and wrist in both open and closed positions, which together can amount to 36 measurements. “The idea came from a therapist who some time ago said: can’t you make something that reduces the time we need to spend measuring a hand with a goniometer? Because it’s currently done by hand and that just takes a lot of time.”

30,000 Photos

“I initially spent time here exploring what possibilities there were and eventually found 29 software programs on the internet. Whether they could actually do it and be accurate was the second question. After a selection process, I came down to three tools that I started testing and eventually, we settled on one program. It determines the skeleton based on the photo of the hand and a dataset of 30,000 photos. All joint points of the skeleton were manually determined in all the photos of that dataset, so the program can make an estimation based on the dataset.”

“If you take multiple photos simultaneously from different angles and combine them—exactly what the Mano-X does—you must be able to accurately determine the angle of the joints. For this, I have written a special program. We plan to continue testing it in the coming months. Where is the program strong and where does it falter? For instance, I found it struggled with hands that have a lot of pigmentation. Not in terms of dark skin, but with pigmentation spots that many older people have. And it’s extremely important that the program measures accurately even then. However, by applying a number of filters, it seems to be working well now.”

“We will also ask several hand therapists exactly what they want. Do they always measure the entire hand or just a part of it? Do they always measure all the joints? And what do they expect from a measurement with a scanner? Based on what they indicate, we will determine exactly what we need to make.”

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Thirty Seconds

The addition of the measurement function can save therapists significant time. On average, manually measuring the angles of the joints takes about five minutes. According to current tests, the scanner should be able to make the measurements in about thirty seconds. “If you extend that to the entire process of rehabilitation, it really saves a lot of time that you can then spend exercising the hand or other parts of the treatment.”

But the project probably doesn’t end there. The Mano-X scanner is a substantial device that creates a 3D model of the hand based on 64 photos. According to Sherida, determining the angles of the joints probably requires less data. One idea is to work with R&D to explore the possibilities of combining the Mano-X scan with imaging via your own iPhone. “Then you might be able to do measurements at home, for instance.”

Another idea is to develop an app for rehabilitation games together with software engineers. These would entice the patient to actually start and continue doing the prescribed exercises at home. This remains one of the challenging aspects of rehabilitation: doing all the exercises even outside of therapy sessions, especially when things are getting better.

But for now, she will primarily continue her research: finding out what works and what therapists need. What will this lead to? She will find out, she says: “If I’ve learned one thing here, it’s that your assumptions often don’t hold up!”

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