Walking aids prevent 'freezing' in Parkinson's disease

Video: How a Parkinson's patient benefited from the device. © Harvard Seas

It starts with stumbling steps and then complete blockage when walking. Apparently, the frustrating and dangerous “freezing” that occurs when Parkinson's patients move can be prevented by gentle tugging at the right moment: researchers have developed and successfully tested a wearable robotic system that could enable sufferers to walk fluently again and thus improve their quality. from life .

More than nine million people are affected worldwide: In Parkinson's disease, some of the nerve cells in the brain in which the neurotransmitter dopamine is produced die. This leads to the typical symptoms of neurodegenerative disease. In addition to the well-known muscle tremors and other motor disturbances, patients often experience a characteristic weakness when walking: they suddenly lose control of leg movement, resulting in increasingly shorter walking steps, eventually leading to a complete stop.

This so-called freezing is a particularly frustrating and problematic consequence of the disease. Instability associated with occlusion often leads to falls. This can severely limit Parkinson's patients' ability to move and be independent. Previous methods of treating freezing with medications, behavioral therapies, or even surgical interventions were unsuccessful and caused problems. But a new concept developed by a research team led by Jinsoo Kim from Harvard University in Boston can now effectively and practically support Parkinson's patients when running. It is a wearable robotic technology that emerged from previous developments to support people with mobility impairments, such as stroke patients.

Mechanical support does the trick

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

The device consists of a main component that is attached to the waist area via shoulder straps. Inside are sensors and two actuators, each connected via a strap to cuffs worn over the thighs. Based on the movement data recorded by the sensors, the calculation unit of the device determines the wearer's gait phase and triggers the appropriate support: in parallel with the muscle movement, a slight force is exerted on the thighs via the tension bands, supporting natural movement behavior when walking.

“We've found that even a small amount of mechanical assistance from our wearable robotic system can lead to significant improvements,” Walsh says. This became clear during the development of the device and testing related to the application: the team was supported by a 73-year-old Parkinson's patient. He had frequent difficulty walking, which often led to falls. But as it turns out, the device was eventually able to help him regain more freedom of movement. After optimizing the settings, the effect was immediate, the scientists reported: without special training, the patient was able to walk indoors without blocking, and the problem of freezing rarely occurred during outdoor walking. He can also walk and talk to someone at the same time, which previously caused him to freeze.

Promising test success

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

According to them, this concept could also help to better understand the mechanisms of walking impairment, which are still unclear. “We don't know exactly why our approach works so surprisingly well,” says co-author Terry Ellis of Boston University. “It is possible that supporting natural biomechanics affects central processing to control gait,” says the scientist.

Source: John Paulson School of Engineering and Applied Sciences at Harvard University, specialized article: Nature Medicine, doi: 10.1038/s41591-023-02731-8

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