Pain in Parkinson's disease

© 2018 Dr Simon SungPain is a common and disabling symptom in people with Parkinson's disease, but the pathophysiological mechanisms underlying this phenomenon remain poorly understood. Through the use of systematic review, meta-analysis techniques, functional magnetic resonance imaging and psychophysical methods for testing pain sensitivity, this thesis demonstrated that Parkinson’s disease patients had altered central nociceptive processing – characterised by an aberrant increase in brain nociceptive activity to innocuous pressure – and that that this phenomenon likely contributes to the development of clinical pain. The brain pathways that have undergone nociceptive sensitisation predominantly subserve the affective and cognitive domains of pain rather than the sensory discriminative aspects, and may have arisen as a consequence of chronic pulsatile levodopa administration These findings have significant implications on both management and future research directions on pain in Parkinson’s disease. In particular, management of clinical pain in Parkinson’s disease should involve strategies designed to prevent and reverse dopamine-induced sensitisation and utilise treatments that deal more with affective and cognitive dimensions of pain rather than dealing with pain intensity, while future research should focus on identifying the root cause of sensitised nociceptive response in Parkinson’s disease patients and on developing techniques to better disengage this aberrant response