AUTHOR=Stoyanova-Piroth Galina , Milanov Ivan , Stambolieva Katerina 

TITLE=Association between pain threshold and manifested pain assessed using a PD-specific pain scale in Parkinson's disease

JOURNAL=Frontiers in Neurology

VOLUME=Volume 15 - 2024

YEAR=2024

URL=https://www.frontiersin.org/journals/neurology/articles/10.3389/fneur.2024.1420696

DOI=10.3389/fneur.2024.1420696

ISSN=1664-2295

ABSTRACT=Background: The neurodegenerative process in Parkinson's disease (PD) affects both dopaminergic and non-dopaminergic structures, which determines the wide range of motor and non-motor symptoms, including different types of pain. Diverse mechanisms contribute to pain in PD. Abnormal nociceptive processing is considered a distinctive feature of the disease.Objective: In the present study, we use a validated PD-specific pain assessment tool to investigate the self-reported pain in PD patients and to analyze the association with the objective pain threshold.Methods: The RIII component of the nociceptive flexor reflex was assessed in 35 patients with PD and compared to 40 healthy controls. Self-reported pain was measured using the KPPS-BG.A correlation analysis was used to investigate the relationship between the objective nociceptive threshold and PD-pain as assessed by KPPS-BG.Results: PD patients had a significantly lower RIII threshold than control individuals (mean value 6.24 ± SD 1.39 vs 10.33 ± 1.64), when assessed in off. A statistically significant (p<0.05) fair negative Spearman's correlation was observed between the decreased spinal nociceptive threshold and fluctuation-related pain (-0.31). Domain 4 "Nocturnal pain" (-0.21) and KPPS-BG total score (-0.21) showed a weak negative correlation. A negligible positive correlation was found between domain 6 "Discolouration; edema/swelling" and RIII threshold. A higher MDS-UPDRS III score and modified H&Y stage are associated with a decreased nociceptive flexor reflex threshold.The results of the present study demonstrate the important role of increased spinal