Clinical Pain and Neuropsychological Functioning in Parkinson's Disease: Are They Related?

Central Pain in Parkinson's Disease: Behavioral and Cognitive Characteristics

Introduction

Pain is a major nonmotor symptom of Parkinson's disease (PD), and central parkinsonian pain is the core feature of the putative Park pain subtype of PD. This study aimed to explore the cognitive and behavioral profile of PD patients with central parkinsonian pain. Material and Methods. A structured interview was used to identify and characterize pain in a cohort of 260 consecutive PD patients. The Ford classification of pain was applied. The Dementia Rating Scale-2 (DRS-2) and the Impulse Control Disorders in Parkinson's Disease Short Form (QUIP-S) were administered, and patients' smoking habits were recorded. The Unified Parkinson's Disease Rating Scale (UPDRS) was used to assess motor and nonmotor symptoms in off and on conditions.

Results

One hundred and eighty-eight patients (68%) reported pain; and in 41 (22%) of them, the pain was classified as central parkinsonian pain. PD patients with central parkinsonian pain had better cognitive performance in DRS-2 Initiation/Perseveration and Conceptualization subscales but reported more other compulsive behaviors (e.g., hobbyism, punding, and walkabout) and had more current smoking habits than those without pain or with non-central parkinsonian pain. Multiple logistic regression analyses revealed that the DRS-2 Conceptualization subscale, other compulsive behaviors, and smoking habits remained statistically associated with central parkinsonian pain even when other significant covariates were considered. Only patients with pain, regardless of type, had a gambling disorder. Discussion. The study results provide further evidence that pain revealed that patients with central parkinsonian pain are more likely to present compulsive or addictive behaviors, despite having more preserved cognitive performance. Patients with central parkinsonian pain appear to have a distinct phenotype of PD.

Pain Severity and Interference in Different Parkinson's Disease Cognitive Phenotypes

INTRODUCTION

Chronic pain is prevalent in idiopathic Parkinson's disease (PD) with many individuals also experiencing cognitive deficits negatively impacting everyday life.

METHODS

In this study, we examine differences in pain severity and interference between 113 nondemented individuals with idiopathic PD who were statistically classified as having low executive function (n=24), low memory function (n=35), no cognitive deficits (n=54). The individuals with PD were also compared to matched non-PD controls (n=64).

RESULTS

PD participants with low executive function reported significantly higher pain interference (p<0.05), despite reporting similar pain severity levels compared to other phenotypes. These differences remained statistically significant, even after accounting for important confounders such as anxiety and depression (p<0.05).

DISCUSSION

Pain interference in those with lower executive function may represent a target for psychosocial interventions for individuals with pain and PD.