Quantification of Static and Dynamic Balance While Maintaining and Changing Body Position

Abstract

The International Classifi cation of Functioning, Disability, and Health (ICF) provides a comprehensive framework for classifying function. Among the mobility activities of the ICF are those that require the maintaining and changing body position, which in turn depend on static and dynamic stability (balance). This review describes subjective and objective methods that can be used within the laboratory and clinic to quantify static and dynamic balance. There are numerous valid and reliable measures now available to clinicians that quantify static and dynamic balance.T he International Classifi cation of Functioning, Disability, and Health (ICF) is a classifi cation system that encompasses the context of human health and health-related domains .1 In the ICF framework, mobility is classifi ed as an activity that includes "changing and maintaining body position." Clinicians working with older adults need measurements by which postural stability while changing and maintaining body position can be quantifi ed. The purpose of this article is to review measures commonly used to quantify static and dynamic balance and to discuss alternatives for quantifying postural stability while "changing and maintaining body position." Common laboratory measures will be discussed fi rst. LABORATORY MEASURESLaboratory equipment is usually expensive and requires space. However, laboratory equipment typically provides greater accuracy and objectivity for quantifying stability during the maintenance and alteration of body positions. The most commonly used laboratory equipment includes force plates, motion analysis systems, and computerized dynamic posturography. Force platesForce plates integrate multiple force transducers to quantify postural control via mathematical calculation of the excursion of the center of pressure (COP) from ground reaction forces. 2 During quiet standing, one needs to maintain the body's center of mass (COM) within the base of support. However, it does not mean that COP and COM move in the same manner. Horak and Nashner 3 proposed an inverted pendulum model of balance. Horak and Nashner's model demonstrated different movement patterns of COP and COM while standing quietly on a force plate. Dynamic balance, which is required for gait, is a more complex condition. To ambulate, the COM is sometimes outside the base of support and the COP needs to shift between the lower extremities. 2 The quantifi cation of dynamic balance usually combines a motion analysis system and force plates because of the complexity of the movement.Several variables can be derived from the excursions of the COP, such as the root mean square of COP amplitudes in the anteroposterior and mediolateral direction, the path length of COP, the maximum COP displacement in the anteroposterior and mediolateral direction and the mean velocity of COP. 4 The root mean square of COP is the most common calculation used in related topic articles. [5][6][7] The reliability of force plate measures under various conditions has been shown to be good to excellent...

Use of a Short Version of the Activities-specific Balance Confidence Scale in Multiple Sclerosis

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“…[5][6][7][8] Patient-reported outcome measures are inexpensive, are used to identify whether a balance problem exists, and have been proved reliable and valid in assessing a person's balance. 5,6,8 One common self-report measure used to evaluate balance confidence is the 16-question Activities-specific Balance Confidence (ABC) scale. 6,[9][10][11] Balance confidence is important to assess because lower balance confidence has been shown to predict future falls.…”

“…This research has revealed numerous valid approaches to assess balance, including force platforms, clinical assessments such as the Berg Balance Scale, and patient-reported outcome measures. [5][6][7][8] Force platforms are able to quantify small amounts of postural sway, but they are expensive and require space and data processing expertise. 5,6,8 Clinical assessments are used to evaluate the subcomponents that underlie postural control, but they may require clinical expertise to administer.…”

“…[5][6][7][8] Force platforms are able to quantify small amounts of postural sway, but they are expensive and require space and data processing expertise. 5,6,8 Clinical assessments are used to evaluate the subcomponents that underlie postural control, but they may require clinical expertise to administer. [5][6][7][8] Patient-reported outcome measures are inexpensive, are used to identify whether a balance problem exists, and have been proved reliable and valid in assessing a person's balance.…”

Reconceptualizing balance: attributes associated with balance performance

“…7 Operationally, most clinical balance tests involve the performance of multiple tasks and thus conceptually, the maintenance of balance is better characterized as an activity. 8, 9 …”