The patients' perception of prodromal symptoms before the initial diagnosis of Parkinson's disease

Before the occurrence of motor symptoms permits the clinical diagnosis of Parkinson's disease (PD), about or even more than 50% of the dopaminergic neurons of the substantia nigra have degenerated. This time be called the prodromal phase of PD.

To evaluate the time span from onset of first prodromal symptoms to the initial diagnosis of PD as well as the order of symptom occurrence.

Retrospective study of 93 consecutively interviewed PD patients without dementia and 93 sex and age matched controls free of neurodegenerative disorders. A standardized in-house telephone worksheet assessing 19 nonmotor and six early motor signs was used.

A total of 98.8% of all patients interviewed reported to have experienced prodromal symptoms prior to receiving the initial diagnosis of PD. Patients noticed an average of 7.6 different symptoms during this time interval. The mean time span between the recalled onset of any one symptom and PD diagnosis was 10.2 years. In both groups, the course of prodromal sign onset was associated with early neuropathological disease stages proposed by Braak.

These retrospectively gathered data confirm the existence of a long prodromal phase for PD that is consistent with neuropathological staging. A standardized questionnaire assessing such early symptoms may be helpful in identifying subjects at high risk for PD while they are still in the prodromal phase of the disorder.