Use of Stabilometric Platform and Evaluation of Methods for Further Measurments – A Pilot Study

Abstract

The ability to maintain the body's position over its base of support (BOS), whether this base is stationary or noviny, is called balance. Controlling postural sway while standing still is called static balance. However, it is impossible to stand absolutely motionless (21,25). Even when people stand still on both feet, the body sways over its base of support. Postural sway is determined by measuring the location and amount of changes that occurs in the position of the total vertical force vector projected onto a horizontal plane. These measurements determine where the average center of pressure (COP) is located and how much variability of this location occurs during the measurement.Generally, we may state that the way of loading both lower extremities, while standing on stabilometric platform (SP), is in each and every case very individual and influenced by anthropometric variables, such as i.e. height, weight, distribution of the liquids and fats in the body, sometimes also by asymmetric parameters of the body, and at last but not least by former therapeutic and surgery interventions (3).Postural stability (PS) of different subjects has been compared by means of body sway measurements. A common quantitative index of body sway is obtained by observing the subject standing still on a force plate and measuring the length of the trajectory of the COP over the surface of the plate during a specified period of time.The use of a force plate for the determination of COP is being accepted as a method to evaluate postural balance. Unfortunately, there is no generally accepted standard situation under which the tests are carried out, and this makes it difficult to compare our results with those published elsewhere.Lafond, Duarte and Prince (14) use besides their posturographic measurements also other biomechanical variables such as Center of Mass (COM) and Gravity Line Projection (GLP), while standing still projects the COM in the COP. In the present study we considered only the COP. Purposes of the studyThe purpose of this study was to extend experiences with practical issues, such as the reliability of stabilometric measurements, when using stabilometric platforms. For this reason it seems to be useful to treat the following points: 1. a) to estimate variance in error (because we suppose that the measurement error will remain the same during further measurements) in order to evaluate whether the first two tests of standing could be recognized as parallel. b) to estimate the variance in error and the intrasession reliability. 2. to see how many records can be taken per day with respect to healthy older adults and which measures should be taken regarding the surroundings. 139ORIGINAL ARTICLE Summary: Posture in a still stance has been quantified by changes in the center of pressure (COP), in both anterior-posterior (A/P) and medial-lateral (M/L) directions and measured on a single force platform (Bertec PRO VEC 5.0). The purpose of this study was to estimate the variance in error and the intrasession test-retest reliabilit...

Measuring the Balance Control System – Review

“…The general trend is to prefer higher values of reliability coefficient, even when its estimation is kept unpublished. Therefore, it is difficult to say the given reliability coefficients are not only real but really repeatable (24). The importance to assess the repeatability and reliability of stabilometric measurements is evident especially for the reason that if measures of COP are to be used for the diagnosis of pathological population and /or monitoring rehabilitation progress, then the summary measures that are used to quantify changes in COP must not only be stable but also reliable.…”

“…As we reported already in Acta Medica 2007 (24) Fleiss (14) offered opinion about acceptable reliability for tests, proposing guide as folows: -over 0.79 as high -0.40-0.79 moderate -less -poor But the other authors suggested a more rigorous acceptable coefficient of reliability for tests, i.e. Kelley (30) recommanded a minimum of 0.94, Weiner and Stewart (59) suggested 0.85, unfortunatelly they did not indicate how their reliability was measured, so we were not able to make an equivalent measurement, nor the approximation of reliability, reported as well in Acta Medica in 2007 (24). We may state that the range of body sway may increase with every trial i. e. due to fatigue.…”

“…If more than one-third of adults over 65 fall each year (20) and these falls are seen as the primary cause of death and injury among this population, we see the necessity of monitoring of PS in the elderly. Objective measurements were proposed by stabilometric methods (SM) with standardized tests of standing (9,24,28,29,49,53,57,61). The purpose of this review is to report about the stabilization and its measurements that is seen in the related literature destinated to balance control and it's quantification.…”

What Is the Role Body Sway Deviation and Body Sway Velocity Play in Postural Stability in Older Adults?

“…Test A -Double Narrow Stance Eyes Open (DNSEO) known as well as parallel narrow or Romberg stance EO (15,16,22 …”

“…A stabilometric platform is often used to measure BS through Centre of Pressure (COP) recording which is further divided into several indicators. These indicators include: Anterior/Posterior Body Sway Deviation (A/P BSD), Medial/ Lateral Body Sway Deviation (M/L BSD), Anterior/Posterior Body Sway Velocity (A/P BSV), Medial/Lateral Body Sway Velocity (M/L BSV) and Total Body Sway Area (TBSA), are considered as a reliable measure of BS (12,16,21,22).…”