Sensory Re-weighting for Postural Control in Parkinson’s Disease

• Published in: Frontiers in human neuroscience Vol. 13; p. 126
• Main Authors: Feller, Kelly J., Peterka, Robert J., Horak, Fay B.
• Format: Journal Article
• Language: English
• Published: Switzerland Frontiers Research Foundation 17.04.2019; Frontiers Media S.A
• Subjects: Age; balance; Basal ganglia; computational model; Disease; Dopamine; Dopamine receptors; feedback; Information processing; Levodopa; Motor task performance; Movement disorders; Neurodegenerative diseases; Neuroscience; Neurosciences; Parkinson's disease; Posture; Principal components analysis; Proprioception; Sensory integration; Visual stimuli; Oregon; United States > US; feedback; computational model; sensory integration; basal ganglia; balance; Parkinson’s disease
• ISSN: 1662-5161; 1662-5161
• DOI: 10.3389/fnhum.2019.00126

Postural instability in Parkinson's disease (PD) is characterized by impaired postural responses to transient perturbations, increased postural sway in stance and difficulty transitioning between tasks. In addition, some studies suggest that loss of dopamine in the basal ganglia due to PD results in difficulty in using proprioceptive information for motor control. Here, we quantify the ability of subjects with PD and age-matched control subjects to use and re-weight sensory information for postural control during steady-state conditions of continuous rotations of the stance surface or visual surround. We measure the postural sway of subjects in response to a pseudorandom, surface-tilt stimulus with eyes closed, and in response to a pseudorandom, visual-tilt stimulus. We use a feedback control model of the postural control system to interpret our results, focusing on sensory weighting as a function of stimulus amplitude. We find that subjects with PD can re-weight their dependence upon sensory information in response to changes in surface- or visual-stimulus amplitude. Specifically, subjects with PD behaved like age-matched control subjects by decreasing proprioceptive contribution to stance control with increasing surface-tilt amplitude and decreasing visual contribution with increasing visual-tilt amplitude. However, subjects with PD do not decrease their reliance on proprioception as much as age-matched controls for small increases in surface-stimulus amplitudes. Levodopa medication did not affect sensory re-weighting behaviors for postural control. The impairment in PD subject's ability to respond differently to small changes in surface rotation amplitudes is consistent with an increased threshold for perceiving proprioceptive signals, which may result from decreased signal-to-noise in the dopaminergic pathways associated with sensory processing and/or sensory integration.