Abnormal center of mass feedback responses during balance: A potential biomarker of falls in Parkinson’s disease

• Published in: PloS one Vol. 16; no. 5; p. e0252119
• Main Authors: McKay, J. Lucas, Lang, Kimberly C., Bong, Sistania M., Hackney, Madeleine E., Factor, Stewart A., Ting, Lena H.
• Format: Journal Article
• Language: English
• Published: San Francisco Public Library of Science 27.05.2021; Public Library of Science (PLoS)
• Subjects: Aging; Analysis; Balance; Bioinformatics; Biology and Life Sciences; Biomarkers; Biomedical engineering; Body mass; Center of mass; Complications and side effects; Disorders; Division; Editing; Falls; Falls (Accidents); Feedback; Funding; Geriatrics; Health care facilities; Informatics; Medicine; Medicine and Health Sciences; Motor task performance; Movement disorders; Muscle contraction; Muscle function; Muscles; Nervous system; Neurodegenerative diseases; Neurology; Older people; Parkinson's disease; People and Places; Perturbation; Physical Sciences; Physiological aspects; Rehabilitation; Research and Analysis Methods; Research facilities; Reviews; Risk factors; Sensorimotor integration; Sensorimotor system; Social Sciences; Transformations; United States; Atlanta Georgia; United States > US; Georgia
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0252119

Although Parkinson disease (PD) causes profound balance impairments, we know very little about how PD impacts the sensorimotor networks we rely on for automatically maintaining balance control. In young healthy people and animals, muscles are activated in a precise temporal and spatial organization when the center of body mass (CoM) is unexpectedly moved that is largely automatic and determined by feedback of CoM motion. Here, we show that PD alters the sensitivity of the sensorimotor feedback transformation. Importantly, sensorimotor feedback transformations for balance in PD remain temporally precise, but become spatially diffuse by recruiting additional muscle activity in antagonist muscles during balance responses. The abnormal antagonist muscle activity remains precisely time-locked to sensorimotor feedback signals encoding undesirable motion of the body in space. Further, among people with PD, the sensitivity of abnormal antagonist muscle activity to CoM motion varies directly with the number of recent falls. Our work shows that in people with PD, sensorimotor feedback transformations for balance are intact but disinhibited in antagonist muscles, likely contributing to balance deficits and falls.