Background: Pain fluctuations are a characteristic phenomenon in advanced Parkinson's disease (PD), but their temporal association with motor and non-motor symptom (NMS) fluctuations remains largely enigmatic. Moreover, data on their importance for disease severity perception and health-related quality-of-life (hr-QoL) is limited.
Objective: To dissect pain fluctuations with respect to pain type and frequency patterns, and their association with motor and non-motor fluctuations.
Methods: Prospective observational cohort study in advanced PD assessing symptom fluctuations by simultaneous hourly ratings using the PD Home diary (Off, On, Dyskinetic state), a pain diary (assessing 9 pain types) and a non-motor diary (10 key NMS) based on validated instruments.
Results: Forty-seven out of 55 eligible participants with fluctuating PD (51% men, median age 65, median disease duration 10 years) had sufficient datasets (>95% of hours) from 2 consecutive days. Pain was reported in 35% of waking hours with clear circadian rhythm peaking in early morning Off periods and clustering during motor Off state (49% of Off state hours with pain). Main NMS co-fluctuating with pain were "Fatigue" and "Inner Restlessness". Simultaneous assessment of global disease severity by participants revealed that pain was associated with worse disease severity only in motor On and Dyskinetic state but not in Off state, which translated into significant correlations of daily pain times with hr-QoL only during motor On and Dyskinetic state.
Conclusions: Aside from treating motor Off periods, specific recognition of pain particularly during motor On and Dyskinetic state comprises an important aspect for disease management in advanced PD.
Keywords: PD home diary; Parkinson’s disease; diary; dyskinesia; fatigue; motor fluctuations; non-motor fluctuations; pain.
Oscillations of the frequency and severity of pain over the day (also called pain fluctuations) are common in advanced Parkinson’s disease (PD). However, their relationship with oscillations of motor and other non-motor symptoms remains unclear. Moreover, only very little data exists on how pain impacts disease severity perception and quality of life for the patients. The present study thus aimed to better understand pain fluctuations and their association with motor and non-motor symptoms in advanced PD. We conducted a prospective observational cohort study in advanced PD patients. Participants rated their symptoms hourly on two consecutive days using three diaries: the PD Home diary (for motor fluctuations), a pain diary (assessing several pain types), and a non-motor diary covering 10 key non-motor symptoms. Pain occurred during 35% of waking hours with a clear circadian rhythm peaking in the early morning and clustering during motor “Off” states as characterized by pronounced motor symptoms. The main non-motor symptoms associated with pain were “Fatigue” and “Inner Restlessness.” Interestingly, pain severity correlated with health-related quality of life only during motor “On” state (defined as a state with good mobility and motor function) and “Dyskinetic” state characterized by the occurrence of involuntary movements, but not during motor “Off” periods. In conclusion, in managing advanced PD, recognizing pain during motor “On” and Dyskinetic states is crucial beyond just addressing motor “Off” periods. This understanding can significantly impact disease management and improve patients’ quality of life.