The new Parkinson's disease pain classification system (PD-PCS)

Background: Chronic pain is a common non-motor symptom in patients with Parkinson's disease (PD).

Objective: To facilitate the diagnosis of pain in PD, we developed a new classification system the Parkinson's disease pain classification system (PD-PCS) and translated the corresponding validated questionnaire into German.

Methods: A causal relationship of the respective pain syndrome with PD can be determined by four questions before assigning it hierarchically into one of three pain categories (neuropathic, nociceptive and nociplastic).

Results: In the initial validation study 77% of the patients (122/159) had PD-associated pain comprising 87 (55%) with nociceptive, 36 (22%) with nociplastic and 24 (16%) with neuropathic pain. The study revealed a high validity of the questionnaire and a moderate intrarater and interrater reliability. The questionnaire has been adapted into German and employed in 30 patients.

Conclusions: The PD-PCS questionnaire is a valid and reliable tool to determine the relationship of a pain syndrome with PD before classifying it according to the underlying category, facilitating further diagnostics and treatment.