Postural instability and neuropsychiatric disturbance in the overlapping phenotype of essential tremor and Parkinson's Disease

Abstract

Objectives: The aim of this study was to perform a comparative analysis of postural and neuropsychiatric features in patients with essential tremor (ET), various Parkinson's disease (PD) phenotypes, and the phenotype of combined ET and PD (ET-PD).

Methods: 169 PD patients with early (1.0-2.0) and 111 PD patients with advanced (2.5-3.0) stages based on the Hoehn and Yahr scale, 55 patients with ET and 26 patients with ET-PD were enrolled in the study. Motor and non-motor symptoms of patients with PD, ET and ET-PD were studied using standardized scales and stabilometry.

Results: Patients with ETPD had milder manifestations of parkinsonism compared to PD patients at the same stages of the disease. Patients in the advanced PD group showed more pronounced posture and balance impairment compared to all other groups assessed by standardized walking and balance scales. No difference using scales for postural assessment was found between ETPD, ET and early stage PD. Using stabilometry, we discovered that indexes of stabilometric parameters were lower in ETPD patients compared to ET and advanced PD, although no difference between ETPD and early PD was found. PD patients in early stages had lower results in most of the indexes compared to ET.

Conclusion: Here, we conducted for the first time a stabilometric examination of ET-PD patients, which could be helpful in differential diagnosis. This analysis helps expand understanding of the clinical manifestations of PD, ET and ET-PD.

Keywords: Comorbidity; Essential tremor; Gait; Parkinson’s disease; Stabilometry.