Direction-specific postural instability in subjects with Parkinson's disease (original) (raw)
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Postural Muscle Responses to Multidirectional Translations in Patients With Parkinson's Disease
Journal of Neurophysiology, 2003
The postural adaptation impairments of patients with Parkinson's disease (PD) suggest that the basal ganglia may be important for quickly modifying muscle activation patterns when the direction of perturbation or stance conditions suddenly change. It is unknown whether their particular instability to backward postural perturbations is due to specific abnormalities of parkinsonian postural muscle synergies in that direction, not present in other directions. In the present study, we test this hypothesis by comparing the patterns of leg and trunk muscle activation in13 subjects with PD and 13 control subjects in response to 8 randomly-presented directions of horizontal surface translations while standing with either narrow or wide stance.
2018
1 Institute of Physiotherapy, Department of Medicine and Health Sciences, Jan Kochanowski University of Kielce, Kielce, Poland. 2 Department of Histology and Embryology Medical University in Lublin, Lublin, Poland. 3 Department of Emergency Medicine and Disaster, Collegium Medicum in Bydgoszcz, Bydgoszcz, Poland. 4 Nicolaus Copernicus University in Toruń, Toruń, Poland. 5 Department of Physical Education and Sport, Academy of Physical Education in Krakow, Krakow, Poland.
ANALYSIS OF POSTURAL CONTROL STRATEGIES IN PARKINSON'S DISEASE
The evaluation of impairment degree in Parkinson's disease (PD) patients is normally based on symptomatic evaluation scales, such as UPDRS, which are only qualitative and lack quantitative precision. However, it is very difficult to prepare a proper scale for PD patients always suitable and quickly executable in relation to the variety of symptom of this disease. Many scales are applied only to single settings, for example to daily activities or to motor or psychic impairments related to PD. The symptoms shown by the PD patient are different depending on static or dynamic situations. Investigation of corrective responses to small and short perturbations of upright standing, such as force pulses applied to the sternum, might contribute to unveil the mechanisms underlying the neural control of posture. The contributions of the motor components can be divided into 3 classes: (1) muscular, (2) reflex and anticipatory. Manoeuvres based on pushing force pulses applied to the sternum are often used clinically: in fact, they are part of a popular test of functionality of postural control (Tinetti's performance test). One of the long-term goals of our researche is to understand the spinal and supraspinal mechanisms that mediate the control of standing posture, and how they change under pathological conditions (spasticity, Parkinsonian rigidity, ageing, etc), by the use of electromyographic and posturographic responses. In the context of the present paper, we investigated the interaction among the various compensatory mechanisms activated in response to perturbations of standing posture (expected or unexpected, with and without vision): central, reflex and intrinsic (i.e., due to muscle mechanical properties) based on posturographic and electromyographic data.
Postural Control in Individuals with Parkinson’s Disease
Physiotherapy [Working Title]
Parkinson's disease is the second most common neurodegenerative disorder in the elderly population. It is a complex, progressive, multisystem disease associated with motor and nonmotor impairments. Postural instability is a crucial component of functional mobility, often overlooked by both clinicians and patients with Parkinson's disease. It is a refractory drug complication for which rehabilitation is the most effective nonpharmacological aid. However, many interventions are based on empirical experience. Improving knowledge on the pathophysiology of postural control disorders is crucial to understand the multifaceted components affected and thus design specific rehabilitation protocols. This chapter intends to offer a comprehensive overview of the current knowledge on this topic starting from the pathophysiology of postural control disorders occurring in various ecological conditions to the most innovative multidisciplinary rehabilitation approaches.
Motricidade, 2015
Postural sway variability was evaluated in Parkinson's disease (PD) patients at different stages of disease. Twenty PD patients were grouped into two groups (unilateral, 14; bilateral, 6) according to disease severity. The results showed no significant differences in postural sway variability between the groups (p ≥ 0.05). Postural sway variability was higher in the antero-posterior direction and with the eyes closed. Significant differences between the unilateral and bilateral groups were observed in clinical tests (UP-DRS, Berg Balance Scale, and retropulsion test; p ≤ 0.05, all). Postural sway variability was unaffected by disease severity, indicating that neurological mechanisms for postural control still function at advanced stages of disease. Postural sway instability appears to occur in the antero-posterior direction to compensate for the stooped posture. The eyes-closed condition during upright stance appears to be challenging for PD patients because of the associated sensory integration deficit. Finally, objective measures such as postural sway variability may be more reliable than clinical tests to evaluate changes in balance control in PD patients.
The Interaction of Postural and Voluntary Strategies for Stability in Parkinson's Disease
This study assessed the effects of stability constraints of a voluntary task on postural responses to an external perturbation in subjects with Parkinson's disease (PD) and healthy elderly participants. Eleven subjects with PD and 12 control subjects were perturbed with backward surface translations while standing and performing two versions of a voluntary task: holding a tray with a cylinder placed with the flat side down (low constraint - LC) or with the rolling, round side down (high constraint - HC). Participants performed alternating blocks of low and high constraint trials. Parkinson's disease participants accomplished the voluntary task as well as controls, showing slower tray velocity in the high, compared with the low, constraint condition. However, the latency of postural responses was longer in the high constraint condition only for control subjects. Control subjects presented different patterns of hip-shoulder coordination as a function of task constraint whereas PD subjects had a relatively invariant pattern. Initiating the experiment with the high constraint task led to (a) decreased postural stability in PD subjects only, and (b) reduced peak hip flexion in control subjects only. These results suggest that Parkinson's disease impairs the capacity to adapt postural responses to constraints imposed by a voluntary task.
Postural Instability in Parkinson’s Disease: A Review
Brain Sciences
Parkinson’s disease (PD) is a heterogeneous progressive neurodegenerative disorder, which typically affects older adults; it is predicted that by 2030 about 3% of the world population above 65 years of age is likely to be affected. At present, the diagnosis of PD is clinical, subjective, nonspecific, and often inadequate. There is a need to quantify the PD factors for an objective disease assessment. Among the various factors, postural instability (PI) is unresponsive to the existing treatment strategies resulting in morbidity. In this work, we review the physiology and pathophysiology of postural balance that is essential to treat PI among PD patients. Specifically, we discuss some of the reported factors for an early PI diagnosis, including age, nervous system lesions, genetic mutations, abnormal proprioception, impaired reflexes, and altered biomechanics. Though the contributing factors to PI have been identified, how their quantification to grade PI severity in a patient can hel...
Postural inflexibility in parkinsonian subjects
Journal of the Neurological Sciences, 1992
In order to identify the types of postural deficits seen in parkinsonian patients with postural instability, we compared the performance of parkinsonian subjects with young and old control subjects in 3 aspects of postural control: (1) the use of sensory information for postural orientation, (2) the coordination of postural movement patterns in response to surface displacements, and (3) the flexible modification of postural response patterns to changes in support conditions. Parkinsonian subjects had very small sway, even under altered sensory conditions. Postural response lateneies to displacements were also normal. Postural instability was associated with abnormal patterns of postural responses including excessive antagonist activity and inflexibility in adapting to changing support conditions. Some parkinsonian subjects appeared to have difficulty sequencing motor programs for postural correction. The parkinsonian subjects appeared stiffer since the rate-of-change of sway in response to displacements was reduced. Levodopa improved postural coordination but not the flexible adaptation to changing support conditions.
Adaptation of vibration-induced postural sway in individuals with Parkinson's disease
Gait & Posture, 2002
Postural control requires accurate integration of visual, vestibular, cutaneous, and proprioceptive sensory information. Previous research suggests that patients with Parkinson's disease (PD) may have difficulty with this integration process, particularly involving incongruent visual information. The purpose of this study was to determine whether PD patients also show difficulty in adaptation to erroneous proprioceptive information. Postural reactions to soleus muscle vibration were explored in 8 PD patients, 8 healthy elderly, and 8 young adults. Postural sway was recorded using an electromagnetic motion analysis system in four conditions (2 vision ×2 vibration) with four trials in each condition to test subjects' adaptation to the vibrator stimulus. The results showed that PD patients did adapt to the vibration across trials, similar to those of both control groups. It was concluded that PD patients in the early stages of the disease could override inaccurate proprioceptive inputs, relying more on true vestibular and/or visual information. These results suggest that the basal ganglia are not critical for this adaptation process in postural control.
Preparatory postural adjustments in parkinsonian patients with postural instability
The Canadian journal of neurological sciences. Le journal canadien des sciences neurologiques, 1995
Postural instability is a common problem in patients with Parkinson's disease. This paper reports results of a study undertaken to investigate some of the possible mechanisms responsible for this instability. Preparatory postural adjustments associated with a lateral leg raising task were studied in five parkinsonian patients and four age-matched controls. Recordings included ground reaction forces, kinematics, and surface EMG activity from multiple leg muscles. In normal subjects there was a well-defined sequence of events preceding the onset of leg elevation, beginning with a transfer of centre of foot pressure (CP), initially toward the moving leg and then back to the support side, followed by displacement of the trunk toward the support side. In the more severely affected parkinsonian patients, the amplitude of the initial displacement of CP was markedly reduced. The interval between the earliest force changes and the onset of leg elevation was prolonged and the relative tim...