Engineering news
The robotic garment is designed to help users walk without ‘freezing’, one of the most common and debilitating symptoms of the disease. It was developed by researchers at the Harvard John A Paulson School of Engineering and Applied Sciences (SEAS) and the Boston University Sargent College of Health & Rehabilitation Sciences in Massachusetts.
Worn around the hips and thighs, the device gives a gentle push to the hips as the leg swings, helping the patient achieve a longer stride.
When people with Parkinson’s freeze, they suddenly lose the ability to move their feet, often mid-stride, resulting in a series of stuttering steps that get shorter until they stop altogether. These episodes are one of the biggest contributors to falls.
The symptom is treated with a range of pharmacological, surgical and behavioural therapies – “none of which are particularly effective”, the researchers said. Their work demonstrates the potential of soft robotics to treat the frustrating and potentially dangerous symptom instead. It could allow people living with the disease to regain not only their mobility but their independence, they said.
In tests, the device completely eliminated a participant’s freezing while walking indoors, allowing them to walk faster and further than they could without the device’s help.
“We found that just a small amount of mechanical assistance from our soft robotic apparel delivered instantaneous effects and consistently improved walking across a range of conditions,” said Professor Conor Walsh from SEAS, co-corresponding author of the study.
The team spent six months working with a 73-year-old man with Parkinson’s, who – despite using both surgical and pharmacologic treatments – endured substantial and incapacitating freezing episodes more than 10-times a day, causing him to fall frequently. These episodes prevented him from walking around his community and forced him to rely on a scooter to get around.
In previous research, Professor Walsh and his team demonstrated that a soft, wearable device could be used to augment hip flexion and assist in swinging the leg forward, providing an efficient approach to reducing energy expenditure during walking in healthy individuals.
In the new work, the team used the same approach to address freezing. The wearable device uses cable-driven actuators and sensors worn around the waist and thighs. Using motion data collected by the sensors, algorithms estimate the phase of the gait and generate assistive forces in tandem with muscle movement.
The effect was instantaneous, the researchers said. Without any special training, the patient was able to walk without freezing indoors, and with only occasional episodes outdoors. He was also able to walk and talk without freezing, a rarity without the device.
“The suit helps me take longer steps,” the participant said. “When it is not active, I notice I drag my feet much more. It has really helped me, and I feel it is a positive step forward. It could help me to walk longer and maintain the quality of my life.”
The device could also be used to better understand the mechanisms of gait freezing, which is poorly understood.
“Because we don’t really understand freezing, we don’t really know why this approach works so well,” said Professor Terry Ellis from Boston University. “This work suggests the potential benefits of a ’bottom-up’ rather than ’top-down’ solution to treating gait freezing. We see that restoring almost-normal biomechanics alters the peripheral dynamics of gait and may influence the central processing of gait control.”
The work was published in Nature Medicine.
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