According to a new study by scientists at the Southwest National Primate Research Center (SNPRC) at Texas Biomedical Research Institute, marmosets can mimic the sleep disturbances, changes in circadian rhythm and cognitive impairment in people with Parkinson’s disease.

This is a significant development since an effective animal model that can emulate both the motor and non-motor symptoms of Parkinson’s gives scientists a better chance of understanding the processes responsible for changes in the brain caused by the disease.

Parkinson’s disease affects one million people in the United States and 10 million people worldwide. With the aging population, the incidence of the neurodegenerative disorder is on the rise. Each year, 60,000 people are diagnosed with Parkinson’s in the U.S. alone. The hallmark symptoms include tremors, slow movements, balance problems and rigid or stiff muscles. However, non-motor symptoms—including disorders of the sleep-wake cycle and problems thinking clearly—can be just as difficult for patients to handle.

During the study, the researchers tracked marmosets using devices around their necks similar to popular human fitness tracking devices. They wanted to see if the marmosets with induced classic Parkinson’s motor symptoms could also serve as an effective model for non-motor symptoms. In addition, scientists videotaped the animals to monitor their ability to perform certain tasks and how those abilities were impacted over time by the disease.

As it turned out, the marmosets did exhibit both motor and non-motor symptoms similar to those experienced by humans with the disease.

“Most of the early studies in Parkinson’s have been conducted with rodents,” explained lead author and Associate Scientist Marcel Daadi, PhD, leader of the Regenerative Medicine and Aging Unit at the SNPRC. “But there are some complex aspects of this disease you simply cannot investigate using rodents in a way that is relevant to human patients.”

“This study is a great first step,” Dr. Daadi continued. “More studies are needed to expand on these non-motor symptoms in marmosets in the longer-term, and perhaps, include other nonhuman primates at the SNPRC like macaques and baboons.”