The ability to maintain balance underlies the successful performance of most physical activities and daily life task. When balance is insuffient, rehabilitational outcomes may be much impaired. Assessment of balance is essential to the rehabilitation course.

The development of clinical technique for evaluating balance is dependent on a thorough understanding of sensory and motor process underlying normal balance control. Many measures used for describing balance were all with important limitations.

The primary objective of this study was to develop a quantitative measure of balance suitable for effective approach for clinical measurement. One approach to systematic evaluation of balance is accomplished when sensory input were altered among somatosensory, visual and vestibular for postural orientation and when divided into static and dynamic state. To provide this conditions, we designed a method 'balance index' which was tested under several different conditions that restrict visual, surface sensory input and produce inaccurate postural reaction by tilting, moving on wheel chair, standing on one leg. Timed performances for assessment criteria under each conditions were then observed in amount of sway or postural reactions for a period of 10 seconds. Quantifying include a numeric ranking of six scales for each unit test. Total score is maximally 40 ratings both in the sitting and standing balance index.

The analyzed results from examining 50 healthy adults and 20 stroke patients were that the normal range of scoring represented 38.3±0.8 in sitting, 34.5±2.7 in standing, balance index, but these values were significantly dropped in stroke patients to 27.8±13.9 in sitting, 21.0±6.9 in standing position. And a decrease in index of normal adults was first found in the aged from 50∼59 years in sitting and 40∼49 years in standing, and no difference were apparent when comparing the two sexes. Both intra- and interrater test reliabilities were high, which indicates that index seems to be a fairly constant parameters.

We suggest that this test is a useful screening tool not only offering quantitative, objective data about balance but also inexpensive, easily administered for examining sitting and standing balance in clinics.