Pilomotor function is impaired in patients with Parkinson's disease: A study of the adrenergic axon-reflex response and autonomic functions

•We studied pilomotor function in Parkinson's disease using axon-reflex analysis.•Pilomotor axon-reflex responsiveness is reduced in early stages of Parkinson's disease.•Pilomotor dysfunction correlates with severity of autonomic symptoms.•Sudomotor and vasomotor function are similarly impaired.•Pilomotor axon-reflex responsiveness might be a useful disease marker.