Effects of deep brain stimulation and levodopa on postural sway in Parkinson's disease.

Department of Electronics, Computer Science and Systems, University of Bologna, Bologna, Italy.
Journal of Neurology Neurosurgery & Psychiatry (Impact Factor: 6.81). 10/2002; 73(3):267-74.
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To quantify postural sway in subjects with Parkinson's disease and elderly controls, and determine the effects of Parkinson's disease, deep brain stimulation, levodopa, and their interactions on postural control during quiet stance.
Centre of foot pressure (CoP) displacement under each foot was measured during three 60 s trials of quiet stance with eyes open in 11 controls and six patients with Parkinson's disease. Subjects with Parkinson's disease were tested in four treatment conditions: off both deep brain stimulation and levodopa (off condition); on deep brain stimulation; on levodopa; and on both deep brain stimulation and levodopa. The variables extracted from CoP included: root mean square distance (rms), mean velocity, 95% power frequency (f(95%)), area of the 95% confidence ellipse (ellipse area), direction of its major axis (mdir), and postural asymmetry between the feet.
rms and area of postural sway were larger than normal in subjects with Parkinson's disease in the off condition, increased further with levodopa, and significantly decreased with deep brain stimulation. Mean velocity and f(95%) were also larger than normal but were restored to normal by all treatments, especially by deep brain stimulation. The combined effect of deep brain stimulation and levodopa resulted in a postural sway that was an average of the effect of each treatment individually. Levodopa increased sway more in the mediolateral than in the anterior-posterior direction. Subjects with Parkinson's disease had asymmetrical mean velocity and f(95%) between the feet, and this asymmetry increased with levodopa but decreased with deep brain stimulation. The f(95%) of the CoP correlated with tremor, posture, and gait subcomponents of the unified Parkinson's disease rating scale.
Subjects with Parkinson's disease have abnormal postural sway in stance. Treatment with levodopa increases postural sway abnormalities, whereas treatment with deep brain stimulation improves postural sway. Quantitative evaluation of static posturography may be a useful adjunct to clinical measures in patients with Parkinson's disease.

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Available from: Lorenzo Chiari, Oct 09, 2015
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    • "The uses of dopaminergic drugs or deep brain stimulation do not provide significant improvements of BD, probably due to a neuropathological process spreading towards nondopaminergic pathways [3]. Moreover, previous studies have demonstrated that treatment with levodopa increases postural sway in patients with advanced PD [4]. BD is characterized by alterations of postural control strategies during standing tasks responding to an unexpected destabilizing perturbation or performing voluntary movements [5]. "
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    ABSTRACT: Balance dysfunction (BD) in Parkinson’s disease (PD) is a disabling symptom, difficult to treat and predisposing to falls. The dopaminergic drugs or deep brain stimulation does not always provide significant improvements of BD and rehabilitative approaches have also failed to restore this condition. In this study, we investigated the suitability of quantitative posturographic indicators to early identify patients that could develop disabling BD. Parkinsonian patients not complaining of a subjective BD and controls were tested using a posturographic platform (PP) with open eyes (OE) and performing a simple cognitive task [counting (OEC)]. We found that patients show higher values of total standard deviation (SD) of body sway and along the medio-lateral (ML) axis during OE condition. Furthermore, total and ML SD of body sway during OE condition and total SD of body sway with OEC were higher than controls also in a subgroup of patients with normal Berg Balance Scale. We conclude that BD in Parkinsonian patients can be discovered before its appearance using a PP and that these data may allow developing specific rehabilitative treatment to prevent or delay their onset.
    Parkinson's Disease 04/2015; 2015(10). DOI:10.1155/2015/520128 · 2.01 Impact Factor
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    • "However, this apparent paradox might be consistent with the postural inflexibility observed by Horak et al. (1992). On the other hand, as noted by Rocchi et al. (2002), there is no agreement among researchers on the specific features of sway in quiet standing that characterize Parkinson's disease, although the term " abnormal " is frequently used to describe such patterns, with the implicit assumption that abnormal sway means excessive sway. In any case, the issue of physiological versus pathological sway size should be carefully reexamined in the context of optimal motor variability (Stergiou et al. 2006). "
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    ABSTRACT: The time course of the center of pressure (CoP) during human quiet standing, corresponding to body sway, is a stochastic process, influenced by a variety of features of the underlying neuro-musculo-skeletal system, such as postural stability and flexibility. Due to complexity of the process, sway patterns have been characterized in an empirical way by a number of indices, such as sway size and mean sway velocity. Here, we describe a statistical approach with the aim of estimating "universal" indices, namely parameters that are independent of individual body characteristics and thus are not "hidden" by the presence of individual, daily, and circadian variations of sway; in this manner it is possible to characterize the common aspects of sway dynamics across healthy young adults, in the assumption that they might reflect underlying neural control during quiet standing. Such universal indices are identified by analyzing intra and inter-subject variability of various indices, after sorting out individual-specific indices that contribute to individual discriminations. It is shown that the universal indices characterize mainly slow components of sway, such as scaling exponents of power-law behavior at a low-frequency regime. On the other hand, most of the individual-specific indices contributing to the individual discriminations exhibit significant correlation with body parameters, and they can be associated with fast oscillatory components of sway. These results are consistent with a mechanistic hypothesis claiming that the slow and the fast components of sway are associated, respectively, with neural control and biomechanics, supporting our assumption that the universal characteristics of postural sway might represent neural control strategies during quiet standing. © 2015 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of the American Physiological Society and The Physiological Society.
    03/2015; 3(3). DOI:10.14814/phy2.12329
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    • "Background Many posturography studies investigated the effects of specific diagnosis modes on balance and postural control. A mode that received considerable attention is the possible effect of posture movement on signal control in different types of posturography.[16] The effect of exercise has to be investigated with the posture movement in posturography . "
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    ABSTRACT: A signal transformation system of posture movement for the stable state was designed in order to measure the bio-physical signal. To estimate the subject in a stable state on the basis of the bio-physical signal in the posture movement, the conditions of vision, vestibular, somatosensory apparatus and the central nervous system (CNS) were detected. Based on the vision condition, there was a greater average variation (Vi-alpha(AVG-MAX) and Vi-alpha(AVG-MIN)) in position with eyes closed and eyes opened (PC and PO), which was 27.11 +/- 6.36 units. The vestibular condition showed a slightly larger average variation (Ve-alpha(AVG-MAX) and Ve-alpha(AVG-MIN)) in the body position with PC and PO, which was 6.60 +/- 1.65 units. The somatosensory condition demonstrated a lower average variation (So-alpha(AVG-MAX) and So-alpha(AVG-MIN)) in position with PC and PO that amounted to 3.653 +/- 2.424 units. The CNS condition was confirmed to indicate very little average variation (C-alpha(AVG-MAX) and C-alpha(AVG-MIN)) in body position with PC and PO that was at 0.401 +/- 0.56 units. As the model depends on the bio-physical transformation system of posture movement, the average values of these perturbations were computed (0.01-2 Hz, range of Fourier frequency). The system consists of a data algorithm, an acquisition system, a data signal processing unit and a network system for the evaluated stability.
    Biotechnology & Biotechnological Equipment 11/2014; 28(sup1):S21-S27. DOI:10.1080/13102818.2014.949042 · 0.30 Impact Factor
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