The Narrow Ridge Balance Test: a measure for one-leg lateral balance control.

The assessment of balance capacity for people with widely different balance abilities is an important issue in clinical practice. We propose the narrow ridge balance test as a sensitive tool to assess one-leg balance capacity. In this test, participants are asked to perform single-leg stance on ridges of gradually decreasing width (100, 80, 60, 40, 20, 10, and 4mm). An outcome measure was developed, base on time in balance in relation to the gradually decreasing ridge width. To evaluate the sensitivity and discriminating power of the test, we applied it to two groups of participants, a group of young participants (age 20-30 years) and group of healthy elderly participants (age 60-80 years). The test showed to sensitively differentiate between the two groups, showing lower scores for the elderly. Furthermore, the test appeared to identify large within-group differences. A special feature of this setup is that the difficulty of the test increases with the balance capacity of the participant. In this way, each participant is exposed to the maximally challenging task, and a broader variety of balance control mechanisms come into play. Finally, the outcome score of the new test was contrasted to conventional measures of standing balance, showing good agreement.