In a cross-sectional cohort of 344 PD patients, cognitive impairment (56.4%) was associated with higher overall pain severity and specific pain subtypes (chronic, central, visceral, off-period dystonia, radicular), with MMSE scores correlating with chronic, radicular, and visceral pain.

Although not mechanistic, the study identifies clinically measurable pain phenotypes linked to cognitive decline that could help stratify patients, prioritize symptom-targeted interventions, and refine inclusion criteria for trials addressing cognition or pain in Parkinson's disease.

PURPOSE: To investigate the impact of different pain subtypes on cognitive function in patients with Parkinson's disease (PD). PATIENTS AND METHODS: A total of 344 patients with PD were enrolled in this cross-sectional study, comprising 187 males (54.4%) and 157 females (45.6%), with ages ranging from 32 to 84 years old. Demographic and clinical data were collected, including age, disease duration, levodopa equivalent daily dose (LEDD), and scores on the Unified Parkinson's Disease Rating Scale part III (UPDRS-III), Hoehn and Yahr (H&Y) scale, Pittsburgh Sleep Quality Index (PSQI), King's Parkinson's Disease Pain Scale (KPPS), Visual Analogue Scale (VAS), Mini-Mental State Examination (MMSE), Activities of Daily Living (ADL) scale, Hamilton Depression Rating Scale (HAMD), and Hamilton Anxiety Rating Scale (HAMA). RESULTS: Cognitive impairment was present in 56.4% of patients with PD. Compared with those with normal cognition, patients with cognitive impairment were older, had a later age at onset, more severe motor symptoms, higher levels of anxiety and depression, and greater pain severity. Specifically, they reported more chronic pain, central pain, visceral pain, "off" period dystonia, discoloration/swelling, and generalized lower abdominal pain (p < 0.05). Moreover, MMSE scores were positively correlated with chronic pain, radicular pain, and visceral pain (p < 0.05). CONCLUSION: Cognitive impairment in PD is closely associated with pain severity, with certain pain subtypes exerting a stronger influence on cognition.