Parkinson’s may change the way emotions manifest in body: Study
Sensations shift to different areas in Parkinson's patients
Parkinson’s disease may change the way basic emotions — such as anger, disgust, fear, happiness, sadness, and surprise — are felt in the body, a study suggests, opening up new perspectives into the disease’s nonmotor symptoms and how they’re managed.
“The results of our study raise many interesting questions about the role of emotions in the symptoms of Parkinson’s disease,” principal investigator Juho Joutsa, MD, PhD, professor of neurology at the University of Turku in Finland, said in a university press release.
The study, “Bodily Maps of Symptoms and Emotions in Parkinson’s Disease,” was published as a brief report in Movement Disorders.
While Parkinson’s is best known for its motor symptoms, it also brings about a range of nonmotor symptoms, from mood changes and sleep problems to cognitive decline, including trouble remembering and thinking, which can impact emotional well-being.
Emotions produce physical responses — such as a racing heartbeat or surging blood pressure — that shape the way people act. It’s been suggested that people with Parkinson’s may have trouble understanding social cues and how emotions make them feel.
Mapping emotions on the body
Joutsa’s team, from the University of Turku and Turku University Hospital, studied whether emotions produce the same physical responses in people with Parkinson’s as they do in healthy individuals by creating body images of emotional reactions, which they called bodily emotion maps.
The study looked at 380 people with Parkinson’s and 79 healthy individuals who served as controls. The mean age for both groups was 67. While the Parkinson’s group had more men and lower education levels, this didn’t influence the results, the researchers noted.
First, patients were asked to describe the body areas where they were experiencing motor and sensory symptoms (clumsiness, stiffness, tremor, numbness, and pain) and bodily sensations associated with basic emotions (anger, disgust, fear, happiness, sadness, surprise, and neutral) by coloring in an outline of a human figure shown on a computer screen.
Clumsiness mapped primarily to the distal limbs, stiffness to the trunk and limbs, and tremor to the hands. “The bodily maps of … motor symptoms matched well with clinical localization of these symptoms,” the team wrote.
Unlike motor symptoms, which were experienced in different areas of the body by Parkinson’s patients than by controls, numbness and pain mapped to the same areas in both groups. However, bodily patterns were more widespread in Parkinson’s than in controls.
To study how patients experience emotions compared with controls, the researchers asked the participants to think carefully about their responses to anger, disgust, fear, happiness, sadness, surprise, or a neutral emotion, and then separately color in the areas of the body where they would feel a loss or an increase of sensation. The body outline mapping emotions didn’t separate the front side from the back, “because emotions are typically localized inside the body rather than superficially,” the researchers wrote.
Anger sensation reduced, shifted in Parkinson’s patients
Compared with controls, patients described no or less intense emotional responses, possibly because of a dysfunction of the autonomic nervous system — the network of nerves that control automatic bodily functions such as heart rate and blood pressure — often seen in Parkinson’s.
This difference was most pronounced in the sensation of anger, which for controls was focused in the chest area, while in Parkinson’s patients it was reduced and shifted to the abdominal region as the disease progressed.
The team noted that none of the emotion-related sensations was “associated with levodopa equivalent daily dose,” a measurement that standardizes the effectiveness of various Parkinson’s medications.
In addition to anger, patients localized the sensations of disgust, fear, and surprise to different areas compared with controls. Bodily patterns of happiness and sadness were less widespread in patients than in controls, suggesting Parkinson’s changes how emotions are felt in the body.
“The non-motor symptoms of Parkinson’s disease have a significant impact on the patients’ quality of life,” said researcher Kalle Niemi, MD, who led the study. “The results of our study highlight yet another non-motor phenomenon.”
While the clinical relevance of the results has yet to be determined, the team suggests bodily emotion mapping could be used to study other neurological diseases. “Extending our research method to other diseases offers new possibilities for neurology research,” Joutsa said.
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