Sensory Symptoms and Sensorimotor Distortion in Parkinson’s Disease

Parkinson’s disease (PD) is, with good reason, conventionally considered a movement disorder. James Parkinson declared “the senses…uninjured” in the first paragraph of his monograph. However many patients with PD do experience unpleasant sensations, and for some these sensory symptoms are the biggest problem. The first half of this chapter focuses on these unpleasant somatic sensations occurring independent of or out of proportion to the cardinal motor symptoms. Vision and smell are not addressed, and pain as an extreme of dysesthesia is considered only to a limited extent. In the second half, attention is given to kinesthesia, which appears to be defective in PD. This is not a symptom as such, as patients are not conscious of it, but distortions of input and processing of interoceptive information may contribute to bradykinesia, dyskinesias, and postural instability, among other parkinsonian signs.