Wissel BD, et al. - This study entailed an identification of the demographic and clinical features of Parkinson's disease (PD) associated with functional neurological features. Based on the observations it was reported that a subtype of PD with functional neurological features was familial in one-fourth of cases. It exhibited a connection with more psychiatric than motor disability and greater use of diagnostic and healthcare resources compared to those without functional features. Data displayed that functional manifestations could be prodromal to PD in one-third of patients.

Methods

• Data was extracted via a standardised form from electronic records of 53 PD patients with associated functional neurological disorders (PD-FND) across 8 movement disorders centres in the USA, Canada and Europe.
• Eligible candidates were matched for age, gender and disease duration to PD patients without functional features (PD-only).
• A comparison was performed between both groups after adjusting for clustering effect with the aid of Logistic regression analysis.

Results

• In 34% of cases, the functional symptoms preceded or co-occurred with PD onset, nearly always in the most affected body side.
• In contrast with PD-only subjects, PD-FND appeared to be predominantly female (68%), exhibited longer delay to PD diagnosis, greater prevalence of dyskinesia (42% vs 18%; P=0.023), worse depression and anxiety (P=0.033 and 0.025, respectively), higher levodopa-equivalent daily dose (972±701 vs 741±559 mg; P=0.029) and lower motor severity (P=0.019).
• Additionally, subjects demonstrated greater healthcare resource utilization and a higher use of [(123)I]FP-CIT SPECT.
• These patients also displayed a greater tendency of having had a pre-existing psychiatric disorder (P=0.008) and a family history of PD (P=0.036).