Normal balance is defined as the ability to maintain the center of body mass over its base of support with minimal sway. Postural control underlying balance involves both sensory and motor processes to organize orientation input from somatosensory, visual, and vestibular system and to coordinate the action of trunk and leg muscles into discrete postural response synergies. Decreased balance in standing and walking is a common problem in the patients with head injury, stroke, vestibular dysfunction, musculoskeletal injury, and elderly and is often a challenging problem for rehabilitation of these patients.

The purpose of this study is to quantify the static and dynamic postural sway using force platform in normal persons and patients with brain lesion to obtain the baseline data for future evaluation of patients with balance deficit, and to define the characteristics of balance problem in the patients with brain lesion. For this purpose, we develop the clinical balance score system I and II. We subsequently compare the clinical balance scores with the static postural sway measured by movement of center of pressure to test the value of clinical balance scoring system. The results are as follows;

1) The static and dynamic postural sway is significantly higher in the persons at seventh decades of age than those in third or fifth decades.

2) There was no significant difference between male and female in the static and dynamic postural sway.

3) The static path sway was significantly higher when tested with eyes closed than with eyes opened.

4) In the patients with brain lesion, both static and dynamic postural sway were remarkably higher than normal persons.

5) Clinical balance score I was more correlated with static postural sway measured by movement of center of pressure than clinical balance score II.