Using Canadian Primary Care Sentinel Surveillance Network data to examine depression in patients with a diagnosis of Parkinson disease: a retrospective cohort study

Prevalence of functional (psychogenic) parkinsonism in two Swiss movement disorders clinics and review of the literature

BACKGROUND

Functional parkinsonism (FP) is considered rare but no studies have looked at its frequency. Case series have described high rates of comorbidity with Parkinson's disease (PD), suggesting a possible association between these conditions.

OBJECTIVES

To study the prevalence, epidemiology and clinical features of FP and its association with PD.

METHODS

We conducted a cross-sectional population-based prevalence study as well as a chart review of cases who received a diagnosis of FP over a 10-year-period in two movement disorder clinics in Switzerland. Epidemiological data regarding FP features were collected. The co-occurrence of PD, psychiatric disorders and other functional disorders were recorded. Clinical differences between FP and FP+PD groups are presented and discussed in light of a literature review.

RESULTS

The crude prevalence of FP was 0.64 per 100,000 in our population. FP represented 0.24% of patients with parkinsonism. Among 12 FP cases, female gender predominance (87%), mean age of onset of 45.5(±13.3 Standard deviation SD) years and prolonged diagnostic delay (mean 59±75 SD months) was found. Six patients had an additional diagnosis of PD, 83% of depression and 66% of other functional neurological disorder. In four patients with FP+PD, FP preceded PD by 6 to 56months.

CONCLUSIONS

These results suggest that FP should be considered in the differential diagnosis of patients presenting with parkinsonism. The high rate of co-occurrence with PD emphasizes the importance of long-term follow up of these patients. The observation that FP often precedes PD should be verified in prospective studies.

Correction: Using Canadian Primary Care Sentinel Surveillance Network data to examine depression in patients with a diagnosis of Parkinson disease: a retrospective cohort study

[This corrects the article on p. E417 in vol. 4.].