Two recent studies indicate that those with Parkinson's disease, who often feel socially isolated, have difficulty recognizing emotions expressed by other people through facial movement and their voices.

In the first study, published recently in Neuropsychology. researchers reviewed data from nearly 1,300 participants that showed there was a strong connection between the disease and the inability to recognize emotions, particularly negative ones. The second study focused on the affect of deep brain stimulation, a common treatment for people living with Parkinson's, on the recognition of fear and sadness shown in facial expressions.

"Having Parkinson's predisposes an individual to errors in emotion recognition," said Heather Gray, one of the researchers who worked on the first study, which was conducted at Harvard Medical School and Tufts University. "The research in France," – a reference to the second study at Centre Hospitalier Universitaire de Rennes – "along with previous studies, indicates that deep brain stimulation produces an even more severe deficit."

The Feinstein Institute for Medical Research within the North Shore-LIJ Health System has numerous clinical trials focusing on Parkinson's disease. One trial is studying the impact of the nutritional supplements folic acid and L-methylfolate on the progression of Parkinson's in patients who have an antibody that affects how folate works on the brain.