Novel postural sway task test European Journal Translational Myology - Basic Applied Myology 2013; 23 (3): 81-84 - 81 - Reliability of novel postural sway task test Milan Sedliak (1), Ján Cvečka (1), Veronika Tirpáková (1), Stefan Löfler (2,3), Nejc Šarabon (4), Helmut Kern (2,3), Dušan Hamar (1) (1) Faculty of Physical Education and Sports, Comenius University, Bratislava, Slovakia; (2) Department of Physical Medicine and Rehabilitation, Wilhelminenspital, Vienna, Austria; (3) Ludwig Boltzmann Institute of Electrical Stimulation and Physical Rehabilitation, Vienna, Austria; (4) University of Primorska, Science and Research Centre, IKARUS, Koper, Slovenia Abstract The purpose of this study was to examine the reliability of parameters obtained from a novel postural sway task test based on body movements controlled by visual feedback. Fifty-nine volunteers were divided into two groups. The first group consisted of young (n = 32, 16 females and 16 males, age: 25.2 ± 3.4 years) and the second group of elderly individuals (n = 27, 17 females and 10 males, age: 75.7 ± 6.9 years). Participants stood in parallel on a computer based stabilographic platform with the feet approximately a shoulder width apart, the toes slightly pointing outwards, the hands placed on the hips. The computer screen was placed approximately 1.5 meter from the platform at a height of subjects’ eyes. An instanta neous visual feedback of participant’s centre of pressure (COP) was given in a form of a blue cross visible on the screen. Participants were instructed to keep the blue cross driven by movements of their hips as close as possible to a predefined curve flowing on the screen. Out of the 6 parameters studied, only the average distance of COP from the curve line and the sum of the COP crossings through the curve line showed high reliability. Correlation between these two highly reliable parameters was -0.89. There was also a statistical difference (p<0.001) between young and elderly in both the average distance of COP from the curve line and the sum of the COP crossings through the curve. To conclude, the novel postural sway task provides a simple tool with relatively low time burden needed for testing. The suggested output parameters measured are highly reliable and easy to interpret. Key Words: balance, centre of pressure, postural control, task test, visual feedback European Journal Translational Myology - Basic Applied Myology 2013; 23 (3): 81-84 Maintaining an upright posture is an essential part of still standing as well as basic human locomotion types e.g., walking and running. Hence, the evaluation of postural control has been widely used in research and clinical settings in various populations, ranging from elderly patients to athletes [11,7]. One of the most widely used methods is recording the movement of the centre of pressure (COP) during still standing, so called static balance. The COP is the point of application of the resultant ground reaction force vectors. Typically, a subject is standing on a force platform, which allows recording the COP sway exerted to maintain the centre of mass (COM) as still as possible. These types of tests, which analyse the sway of COP, have been repeatedly reported to have a good reliability level (for a review see e.g., [13]). A recent report of Robinovitch et al. [12] showed that the most common reason of falls among the elderly is incorrect COM transfer during movement e.g., during standing up or stepping sideway. There are also several laboratory and field tests which examine stability while a subject voluntarily or involuntarily moves the whole or parts of their body and hence induces COM transfer. They range from tests with minimal requirement for instrumentation to computerized dynamic posturography. For instance, the Star Excursion Balance Test [5] and Functional Reach Test [4] use simple measurements of reaching distance and do not require any electric or electronic devices. Such a simplistic approach has undoubtedly many advantages, but it may, in part, compromise the value of the information obtained. On the other hand, there are complex systems like Equi Test (NeuroCom International, Clackamas, USA) selectively