01 Jul 2011
By Angeline Neo
Walking is such an easy, natural movement that few of us give it a second thought. But before 25-year old Janice Ng is able to take a few steps, she has to mentally map the distance she wants to go first, even if it’s just to cross the room. Every step is deliberate, never random.
Ms Ng has cerebral palsy, a walking and motion disorder caused by damage to the motor control centres of the developing brain. Cerebral palsy may affect one limb, all four, or a combination, making movements abrupt, jerky, uncontrolled and uncoordinated. In Ms Ng’s case, she suffers from “toe-walking” – a condition where her heel and toes don’t rest flat on the ground when she is standing, resulting in her being balanced precariously on her toes. When walking, her feet aren’t able to perform the full range of movements that most people are able to. Not surprisingly, she is prone to tripping and falling.
A brace, known as an ankle foot orthosis, worn on the lower leg and foot to support the ankle, can help people like Ms Ng walk more normally by holding the foot and ankle in the correct position. However, conventional devices can be rigid, preventing the “up-down motion in a natural walking movement”, said Ms Celia Tan, Senior Principal Physiotherapist, Singapore General Hospital (SGH), and Deputy Director of its Allied Health Division.
To address this shortcoming, SGH physiotherapists and a team of Ngee Ann Polytechnic final-year mechanical engineering students worked together to develop an improved device, one which has a moveable ankle joint and a spring at the back. According to Ms Dawn Tan, Principal Physiotherapist, SGH, the device “enables the patient to lift the foot, clear it off the ground and land on his heel”.
The result is a more natural walk and easier mobility. The device gives patients better control of their ankles, which are often weak because muscles in the area lack exercise. With improved control, patients have a lower risk of tripping or falling.
The project, a winner at SingHealth’s Allied Health Innovative Practice Award 2010, was among the many innovations churned out by Ngee Ann Polytechnic’s aspiring engineers. Under an SGH-Ngee Ann Polytechnic programme, in place since 2004, final-year students and hospital staff work to develop devices to improve care and therapy for patients. In the last seven years that Ms Celia Tan has helmed the programme, the hospital has patented three new devices.
“The arrangement allows us to combine our medical experience with the technical expertise that the students have acquired. We give the ideas, they build the prototypes and, together, we create something that is currently unavailable in the market, or construct a better device that can be more efficient in aiding patients’ therapy,” she said.
Building a prototype for a medical device usually takes about nine months. During this time, Ms Tan or a therapist works closely with each group of four to six students. The students sometimes visit the hospital to see therapists at work and speak to patients to understand their requirements.
It took the team 18 months and two attempts to build the improved leg brace. The first model was bulky with a side-loaded spring – functional but not perfect. With fine-tuning, a second prototype was produced – this time, it was lighter, more wearable and effective. It is still undergoing changes, and the team is looking next at ensuring a proper fit.
“If the fit is not right, the patient may suffer blisters and discomfort, which may deter him from using the brace, and stop him from benefiting from proper physiotherapy. An improper fit will also affect control of the ankle, causing more trips or falls,” said Ms Tan.
The foot brace brings hope to patients like Ms Ng, who is testing the device. “I’m actually starting to make a little progress and walk better. I know once we get the fit right, it will help me tackle the problems I have. I hope that in the long run, I won’t have to hunch and can have a proper, upright posture when I walk,” she said.
Ms Ng, who will graduate from university this year, said: “People always tell me that after I graduate, I should get a desk job. But I love to meet and talk to people. I want to move around and see new places. With this leg brace, I’ll be able to move around and experience things I’ve never tried before.”
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