Exercise Found to Improve Nonmotor Symptoms of Parkinson Disease

All types of exercise can improve non-motor symptoms, such as cognitive function, in patients suffering from Parkinson disease (PD), according to a study that appeared earlier this year in the Journal of Parkinson’s Disease.

"The potential of exercise to improve motor and non-motor symptoms is promising and may help to decelerate disease progression in individuals affected by PD," said the study’s lead researcher, Tim Stuckenschneider, MA, in a statement.

In 2016, the Lancet reported that the number of individuals affected by PD is rising worldwide, in part due to an aging population. PD significantly impacts quality of life among individuals with the disorder, their caregivers, and their relatives. The disease also greatly contributes to rising healthcare costs. As many as 57% of patients with PD experience mild cognitive impairment within 5 years of diagnosis. The majority of PD patients who survive 10 or more years eventually develop dementia.

While previous studies have found that exercise could improve motor symptoms of PD, the effect that it could have on non-motor symptoms remains shrouded in ambiguity. "Physical exercise is generally associated with increased cognitive function in older adults, but the effects in individuals suffering from PD are not known," Stuckenschneider said.

Researchers conducted a comprehensive literature review to compile evidence supporting the concept that multiple types of exercise, including resistance training, aerobics, and coordination training could affect domain-specific cognitive function in PD patients.

Researchers examined parallel-group randomized controlled trials published before March 2018. Out of 2000 publications, 11 studies were determined to meet inclusion criteria and contain findings relevant to the review. Data from a total of 508 PD patients, with disease severities ranging from stages 1 to 4 on the Hoehn & Yahr scale, were examined.

• In 4 studies, positive effects of exercise on memory, executive function, and global cognitive function were found with no negative effects on any cognitive domain.
• In 5 studies, a significant between-group effect size (ES) was identified for tests of specific cognitive domains. Aerobic exercise was found to have a positive effect on memory and executive function. A combination of resistance and coordination exercise was found to have a positive effect on global cognitive function.
• In 2 trials, researchers found a significant ES for patients that underwent coordination training, which led to improved executive function compared to control participants who did not exercise.

Researchers determined that all modes of exercise could improve cognitive function in individuals with PD. However, they were unable to determine which exercise mode was the most effective as varying types had different effects on cognitive function. Aerobic exercise was found to most successfully improve memory.

"Exercise therapy needs to be, and often already is, an essential part of therapy in individuals with PD. However, it is mostly used to treat motor symptoms," Stuckenschneider said. "As part of a holistic therapy, the potential of exercise to maintain or improve non-motor symptoms such as cognitive function in individuals with PD needs to be acknowledged, and the most effective treatment options need to be defined. This will not only help practitioners to recommend specific exercise programs, but also ultimately improve the quality of life of the individual."

PD progresses slowly and affects movement, muscle control, and balance. While it was originally believed to be a movement disorder, it is currently known as a heterogeneous multisystem disorder, considering non-motor symptoms of the disease have been shown to have a severe, negative impact on quality of life.

Researchers suggest further studies that directly compare the effects of different modes of exercise on cognitive function are need as the number of high-quality studies that explore the topic remain limited.

“Our work shows that ‘exercise is medicine’ and should routinely be recommended for people with Parkinson’s disease to help combat both the physical and cognitive challenges of the disease,” Stuckenschneider concluded.

Reference

Stuckenschneider T, Askew CD, Menêses AL, Baake R, Weber J, Schneider S. The effect of different exercise modes on domain-specific cognitive function in patients suffering from Parkinson’s disease: a systematic review of randomized controlled trials. J Parkinsons Dis. 2019;9(1):73-95. doi: 10.3233/JPD-181484.