New walking aid prevents “freezing” in Parkinson’s disease

Video: How a Parkinson’s patient benefited from the device. © Harvard SEAS

It starts with tripping steps and then there is a complete blockage when walking. The frustrating and dangerous “freezing” that occurs when Parkinson’s patients move can apparently be prevented by a gentle pull at the right moment: Researchers have developed and successfully tested a wearable robotic system that can enable those affected to walk fluently again and thus improve their quality of life .

More than nine million people worldwide are affected: In Parkinson’s disease, certain nerve cells in the brain in which the neurotransmitter dopamine is produced die. This leads to the typical symptoms of the neurodegenerative disease. In addition to the well-known muscle tremors and other motor disorders, patients often suffer from a characteristic impairment when walking: They suddenly lose control of the leg movement, which leads to increasingly shorter walking steps, which ultimately lead to a standstill.

This so-called freezing is a particularly frustrating and problematic consequence of the disease. The instability associated with the blockages often leads to falls. This can severely limit the mobility and independence of Parkinson’s patients. Previous approaches to treating freezing with medications, behavioral therapies or even surgical interventions have been unsuccessful and problematic. But the new concept from the research team led by Jinsoo Kim from Harvard University in Boston could now effectively and practically support Parkinson’s patients when running. It is a wearable robotic technology that emerged from previous developments to support mobility disabilities, such as stroke patients.

Mechanical support does the trick

“Our approach to preventing freezing in Parkinson’s patients is based on collaboration between engineers, rehabilitation scientists, physical therapists, biomechanists and clothing designers,” says co-senior author Conor Walsh of Harvard University.

New walking aid prevents “freezing” in Parkinson’s diseaseThe device consists of a main element that is attached to the waist area via shoulder straps. Inside there are sensors and two motors, each connected via a drawstring to cuffs that are worn over the thighs. Based on the movement data recorded by the sensors, a calculation unit in the device determines the wearer’s respective gait phase and triggers appropriate support: parallel to the muscle movement, a slight force is exerted on the thighs via the tension straps, which supports normal movement behavior when walking.

“We found that even a small amount of mechanical assistance from our wearable robotic system can lead to significant improvements,” says Walsh. This became apparent during the application-related development and testing of the device: the team was supported by a 73-year-old Parkinson’s patient. He suffered from frequent difficulty walking, which had often led to falls. But as it turned out, the device was ultimately able to help him regain more freedom of movement. After optimizing the settings, the effect was immediate, the scientists report: without special training, the patient was able to walk indoors without blockage, and problematic freezing only rarely occurred during outdoor walks. He could also walk and converse with someone at the same time, which previously typically resulted in freezing.

Promising test success

“Our team was excited to see the positive impact of the technology on our study participant’s walking,” says Kim. The Parkinson’s patient himself explains: “The device helps me take longer steps, and when it’s not active, I notice that I drag my feet a lot more. “The concept can actually help me walk longer distances and improve my quality of life,” said the study participant. However, the researchers emphasize that further development work is now necessary before a finished product can benefit Parkinson’s patients. “The study represents a milestone in the development of technology-based solutions for the treatment of gait freezing,” the researchers write.

According to them, the concept could also help to better understand the mechanisms of walking impairment, which remain unclear. Co-senior author Terry Ellis from Boston University says: “We don’t actually know exactly why our approach works so surprisingly well. “It is possible that the support of normal biomechanics influences the central processing of gait control,” says the scientist.

Source: Harvard John A. Paulson School of Engineering and Applied Sciences, specialist article: Nature Medicine, doi: 10.1038/s41591-023-02731-8

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