Validity of the multi-directional reach test: a practical measure for limits of stability in older adults.

BACKGROUND Falls occur not only in the forward direction, but also to the side and backward. The purpose of this study was to develop a portable and valid tool to measure limits of stability in the anterior-posterior and medial-lateral directions. METHODS Two hundred fifty-four community-dwelling older persons were administered the Berg Balance Test (BBT), the Timed Up & Go Test (TUG), and the Multi-Directional Reach Test (MDRT). For the MDRT, subjects performed maximal reaches with the outstretched arm forward (FR), to the right (RR), to the left (LR), and leaning backward (BR), with feet flat on the floor. Reach was measured by the subject's total hand excursion along a yardstick affixed to a telescoping tripod. RESULTS Mean scores on the MDRT were FR = 8.89 +/- 3.4 in., BR = 4.64 +/- 3.07 in., RR = 6.15 +/- 2.99 in., and LR = 6.61 +/- 2.88 in. Interclass Correlation (ICC2,1) for the reaches were greater than.92. Reliability analysis (Cronbach's Alpha,.842) demonstrated that directional reaches measure similar but unique aspects of the MDRT. The MDRT demonstrated significant correlation with the BBT sum and significant inverse relationship with the scores on the TUG. Regression analysis revealed that activity level contributed to scores in the forward, right, and left direction and that fear of falling contributed to scores in the backward direction. CONCLUSION The Multi-Directional Reach Test is an inexpensive, reliable, and valid tool for measuring the limits of stability as derived by reach in four directions. Values obtained on relatively healthy community-dwelling older adults serve as norms for screening patient populations.