Effects of Parkinson's disease on proprioceptive control of posture and reaching while standing

Abstract

Although previous studies have shown pointing errors and abnormal multijoint coordination in seated subjects with PD who cannot view their arm, the extent to which subjects with PD have problems using proprioception to coordinate equilibrium maintenance and goal-oriented task execution has not been adequately investigated. If a common motor program controls voluntary arm pointing movements and the accompanying postural adjustments, then impairments of proprioceptive integration in subjects with PD should have similar effects on pointing and body center of mass (CoM) control with eyes closed. Ten standing subjects with PD (OFF-medication) and 10 age-matched control subjects pointed to a target with their eyes closed and open. Although pointing accuracy was not significantly different between groups, body CoM displacements were reduced in subjects with PD, but not in controls, when eyes were closed. In addition, with eyes closed, PD subjects showed reduced temporal coupling between pointing and CoM velocity profiles and reduced spatial coupling between pointing and CoM endpoints. This poor coupling with eyes closed could be related to the PD subjects' increased jerkiness of CoM displacements. The different effects of eye closure between control and PD subjects on the CoM displacements, but not pointing accuracy, are consistent with separate motor programs for the pointing and postural components of this task. Furthermore, the decoupling between the two movement components in subjects with PD when they could not use vision, suggests that the basal ganglia are involved in the integration of proprioceptive information for posture-movement coordination. KeywordsMotor control; Pointing; Posture; Whole body; Basal ganglia; Complex movement Patients with severe Parkinson's disease (PD) have problems maintaining balance and coordinating complex goal-directed movements. Previous studies have shown that postural adjustments that accompany voluntary movements are bradykinetic (i.e. slow and weak) in Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. NIH Public Access Author ManuscriptNeuroscience. Author manuscript; available in PMC 2010 November 30. Horak et al. 1992;Gantchev et al. 1996;Frank et al. 2000;Rocchi et al. 2006). Subjects with PD also have smaller than normal limits of stability when asked to lean to their maximum limits (Mancini et al. 2008). Undershooting intended targets for arm pointing, locomotion, and stepping by subjects with PD with eyes closed has been hypothesized to be due to an underestimation of the motor command because of difficulty integrating propr...

The interaction of postural and voluntary strategies for stability in Parkinson's disease

“…Individuals with PD do not promptly adjust the magnitude of their postural responses based on their initial posture (Horak et al 1999;Rocchi et al 2006), direction of perturbation (Chong et al 1999a), instructional set (Chong et al 1999a(Chong et al , 1999b(Chong et al , 2000, or prior experience (Chong et al 1999a(Chong et al , 2000De Nunzio et al 2007). Of particular interest for the present study, individuals with PD have been found to be impaired at integrating control of postural stability with the goal of voluntary tasks such as step initiation (Burleigh-Jacobs et al 1997;Gantchev et al 1996;Rocchi et al 2006), trunk bending (Alexandrov et al 1998), and pointing to a target (Tagliabue et al 2009). Tagliabue et al (2009) showed that as the stability constraint imposed by a pointing task increases, functional integration between the voluntary and postural tasks decreases in individuals with PD.…”

“…Of particular interest for the present study, individuals with PD have been found to be impaired at integrating control of postural stability with the goal of voluntary tasks such as step initiation (Burleigh-Jacobs et al 1997;Gantchev et al 1996;Rocchi et al 2006), trunk bending (Alexandrov et al 1998), and pointing to a target (Tagliabue et al 2009). Tagliabue et al (2009) showed that as the stability constraint imposed by a pointing task increases, functional integration between the voluntary and postural tasks decreases in individuals with PD. The high stability constraint condition led to poorer control of the center of body mass (CoM) in subjects with PD, whereas performance on the voluntary task was unaffected (Tagliabue et al 2009).…”

“…Tagliabue et al (2009) showed that as the stability constraint imposed by a pointing task increases, functional integration between the voluntary and postural tasks decreases in individuals with PD. The high stability constraint condition led to poorer control of the center of body mass (CoM) in subjects with PD, whereas performance on the voluntary task was unaffected (Tagliabue et al 2009).…”

The Effect of Standing Posture-enhancing Exercise on Parkinson’s Disease Patients’ Turning Around Motion

“…This result was similar our study. It was indicated good posture was closely related performing functional movement 21,22) . Parkinson's disease patients performing a balance of visual surround and low-extremity strength training programs improved their equilibrium and strength.…”

Effect of different modes of therapy on vestibular and balance dysfunction in Parkinson’s disease

“…As previously reported by many authors, organization protocols are useful for the assessment of postural control under various sensory conditions and generally accepted as a reliable paradigm of measuring the capacity of the central nervous system to prioritize and reintegrate sensory information. 32,43 Tagliabue et al 40 reported that these patients showed a breakdown in the temporal coordination between postural adjustments and arm reaching during whole body reaching to a target when closing their eyes. Abnormal postural coordination when vision was obscured is consistent with impaired proprioceptive mapping compensated by the use of vision.…”