Research reveals why walking ‘freezes’ in Parkinson’s disease

Monday, September 12, 2022 (HealthDay News) — Researchers think they’ve found out why Causes Parkinson’s disease A person’s limbs become so stiff that at times they can feel frozen in place.

Using a robotic chair equipped with sensors, the research team linked leg muscle activation in Parkinson’s patients to a region of brain It is called the sub nucleus.

This oval-shaped brain region is involved in movement regulation, and data from the chair shows it controls the beginning, end, and volume of a person’s leg movements, according to research published Sept. Translational Medicine Sciences .

“Our results helped reveal clear changes in brain activity associated with leg movements,” said senior researcher Eduardo Martin Moraud, a small principal investigator at the University of Lausanne in Switzerland.

“We can confirm that the same alterations underlie the coding of walking states—for example, changes between standing, walking, turning, avoiding obstacles or going up stairs—and walking deficits such as freezing walking,” Murad said.

Parkinson’s disease is a degenerative disorder in Nervous system Which mainly affect the body’s motor functions.

Parkinson’s patients have trouble regulating the volume and speed of their movements, according to the Parkinson’s Foundation. They struggle to start or stop movements, connect different movements to accomplish a task such as standing up, or finish one movement before they start the next.

The hypothalamic nucleus is part of the basal ganglia, a network of brain structures known to control many aspects of the body’s motor system, said Dr. James Liao, a neurologist at the Cleveland Clinic who reviewed the findings.

“This study is the first to convincingly demonstrate that the basal ganglia powerfully control leg movements,” Liao said. “The significance is that this links basal ganglia dysfunction with the altered gait deficits of Parkinson’s disease.”

To research the effect of Parkinson’s disease on walking, researchers built a robotic chair in which anyone can voluntarily extend their leg from the knee or the chair can do so for them.

The researchers recruited 18 patients with Parkinson’s disease who had severe motor fluctuations and problems with gait and balance. Each patient was implanted with electrodes that can track electrical signals from their hypothalamic nuclei and also provide deep brain stimulation to that area of ​​the brain.

Impulses from the hypothalamic nucleus were tracked while the patients used the chair and later as they stood and walked.

“The fact that all of these aspects of walking are encoded in that region of the brain makes us believe that they contribute to walking function and dysfunction, which makes it an interesting area for treatments and/or for predicting problems before they arise,” Murad said. “We can take advantage of this understanding to design real-time decoding algorithms that can predict these aspects of walking in real time, using only brain signals.”

In fact, researchers have created several computer algorithms that distinguish brain signals for regular steps from those that occur in patients with impaired walking. The team was also able to identify episodes of freezing in patients while performing short walking tests.

“The authors showed that periods of freezing walking can be predicted from recorded neural activity,” Liao said. “Accurate predictions will allow the development of algorithms for change [deep brain stimulation] Patterns in response to periods of freezing, shortening, or even eliminating gait. “

Morwood said these findings could help guide future technologies aimed at improving the mobility of Parkinson’s patients.

“There are high hopes that the next generation of deep brain stimulation therapies, which will work in a closed loop – meaning that they will deliver electrical stimulation in an intelligent and precise way, based on feedback on what each patient needs – may better help alleviate gait and balance deficits.”

“However, closed-loop protocols hinge on signals that can help control the delivery of stimulus in real time. Our results open up such possibilities,” he added.

Dr. Michael Okun, national medical advisor for the Parkinson’s Foundation, agreed.

“Understanding the brain networks that underlie walking in Parkinson’s disease will be important for the future development of treatments,” Okun said. “The main question for this research team is whether the information they collected is sufficient to drive a neurocompensatory system to improve walking ability for Parkinson’s disease.”

more information

The Parkinson’s Foundation has more about the walking and movement difficulties associated with Parkinson’s disease.