People with Parkinson Disease Demonstrate Greater Delay Discounting

Delay discounting, or the perceived value depreciation of a reward over the time it takes to earn it, is steeper in people with Parkinson disease compared with healthy controls, according to a systematic review and meta-analysis published in Behavioural Brain Research.

“Delay discounting is well captured by the expression of the Italian playwright Carlo Goldoni, who in his masterpiece La Locandiera (1752) wrote that it is ‘Better an egg today, than a hen tomorrow,’ which afterwards became a popular proverb,” researchers explained in the study introduction.

Over the past decade, abnormal delay discounting has been reported in several conditions, including Alzheimer disease, autism spectrum disorders, and Parkinson disease. To investigate delay discounting in Parkinson disease more comprehensively, researchers conducted a systematic review and meta-analysis of 21 studies, all of which included at least 1 group of participants with Parkinson disease. The meta-analysis is believed to be the first on delay discounting in Parkinson disease.

In people with Parkinson disease both on and off dopaminergic medication, the meta-analysis found steeper delay discounting than in healthy control subjects, according to the study. 

“These results confirm altered delay discounting in Parkinson disease and suggest an independent influence of the dopaminergic medication and the clinical condition itself,” wrote corresponding author Paola Pennisi, PhD, of the University of Messina Department of Adult and Childhood Human Pathology in Italy, and coauthors.

Reference:
Pennisi P, Salehinejad MA, Corso AM, Merlo EM, Avenanti A, Vicario CM. Delay discounting in Parkinson’s disease: a systematic review and meta-analysis. Behav Brain Res. 2023;436:114101. doi:10.1016/j.bbr.2022.114101