Early balance impairment in Parkinson’s Disease: Evidence from Robot-assisted axial rotations

• Published in: Clinical neurophysiology 2021-10, Vol.132 (10), p.2422-2430
• Main Authors: Zampogna, Alessandro, Mileti, Ilaria, Martelli, Francesca, Paoloni, Marco, Del Prete, Zaccaria, Palermo, Eduardo, Suppa, Antonio
• Format: Article
• Language: English
• Subjects: Balance; Parkinson's disease; Posturography; Reactive postural responses
• ISSN: 1388-2457; 1872-8952
• DOI: 10.1016/j.clinph.2021.06.023

•Patients with Parkinson’s disease manifest abnormal reactive postural responses to axial rotations.•Abnormal reactive postural responses to axial rotations are unresponsive to L-Dopa in Parkinson’s disease.•Patients with Parkinson’s disease without clinically overt postural instability present subclinical balance impairment. Early postural instability (PI) is a red flag for the diagnosis of Parkinson’s disease (PD). Several patients, however, fall within the first three years of disease, particularly when turning. We investigated whether PD patients, without clinically overt PI, manifest abnormal reactive postural responses to ecological perturbations resembling turning. Fifteen healthy subjects and 20 patients without clinically overt PI, under and not under L-Dopa, underwent dynamic posturography during axial rotations around the longitudinal axis, provided by a robotic mechatronic platform. We measured reactive postural responses, including body displacement and reciprocal movements of the head, trunk, and pelvis, by using a network of three wearable inertial sensors. Patients showed higher body displacement of the head, trunk and pelvis, and lower joint movements at the lumbo-sacral junction than controls. Conversely, movements at the cranio-cervical junction were normal in PD. L-Dopa left reactive postural responses unchanged. Patients with PD without clinically overt PI manifest abnormal reactive postural responses to axial rotations, unresponsive to L-Dopa. The biomechanical model resulting from our experimental approach supports novel pathophysiological hypotheses of abnormal axial rotations in PD. PD patients without clinically overt PI present subclinical balance impairment during axial rotations, unresponsive to L-Dopa.