Do gastrointestinal symptoms predict mental problems in Parkinson’s disease?

This study investigated the association between gastrointestinal symptoms and cognitive (thinking and reasoning) impairment (CI) in patients with Parkinson's disease (PD). Researchers suggested that gastrointestinal symptoms predicted CI outcomes in newly diagnosed patients with PD. 

PD is a chronic disease that affects brain cells. These cells lose their ability to control body functions such as movement. However, the disease can also cause CI which consists of the loss of mental skills such as forgetfulness and slow thinking. CI progresses slowly but has very harmful effects. 80% of patients have PD-associated dementia within 15-20 years. 

Prior studies showed that in PD the communication between gut and brain changes in newly diagnosed patients. These changes might lead to disease progression and CI. However, no studies to date have examined the association between gastrointestinal symptoms and CI in PD. 

This study included information about 423 newly diagnosed patients with PD. It included patients without CI, mild CI, and PD related dementia. The rate of gastrointestinal symptoms was measured. These patients were followed-up for up to 5 years. 

Patients with more severe gastrointestinal symptoms tended to have poorer outcomes in talking, seeing, learning and memory. Also, more frequent gastrointestinal symptoms were associated with poorer cognitive performance. 

This study concluded that gastrointestinal symptoms might be a marker of CI in newly diagnosed patients with Parkinson's disease. 

Gastrointestinal symptoms can occur earlier than movement symptoms in PD. Also, they can be influenced by what a person eats. More studies are necessary to evaluate the connection between gastrointestinal symptoms and cognitive impairment in PD.