Table 1.

Documented associations and suggested links between non-motor symptoms (associated with prodromal Parkinson’ disease) and the onset of motor Parkinson's disease.

 Strong to moderate evidenceOlfactory disorders

  • hyposmia6

Sleep disorders

  • rapid eye movement sleep behaviour disorder7

  • excessive daytime sleepiness8

Bowel dysfuction

  • constipation9

  • defecatory dysfunction9,10

Mood disorders

  • major depression11

  • anxiety12

Weak evidenceAutonomic dysfunction

  • erectile dysfunction13

  • urinary dysfunction14

  • orthostatic hypotension15

  • cardiac insufficiencies16

Personality/behaviour-related disorders

  • apathy17

  • anhedonia17

  • cognitive disorders17

Miscellaneous

  • fatigue18

  • pain19

  • sense of imbalance20

  • weight loss21

  • colour vision22