Beam Walking to Assess Dynamic Balance in Health and Disease: A Protocol for the 'BEAM' Multi-center Observational Study

Background: Dynamic balance keeps the vertical projection of the center of mass within the base of support while the center of mass moves. The age-related decrease in dynamic balance is a risk factor for falls. Dynamic balance tests are used to predict the risks for falls and eventual falls but the psychometric properties of most tests assessing dynamic balance are unsatisfactory and comprise no actual loss of balance while walking. Objectives: Using beam walking distance as a measure of dynamic balance, we will determine the psychometric properties, lifespan and patient reference values, the relationship with selected 'dynamic balance tests', and the accuracy of beam walking distance to predict falls. Methods: This cross-sectional observational study will examine healthy adults in 7 decades (n=432) at 4 centers. Center 5 will examine patients (n=100) diagnosed with Parkinson's disease, multiple sclerosis, stroke, and balance disorders. At Test 1, all participants will be measured for demographics, medical history, grip and leg strength, short physical performance battery, static balance on a force platform, and dynamic balance using beam walking (4m-long, 4, 8, and 12 cm wide) under single (beam walking only) and dual task conditions (beam walking while concurrently performing an arithmetic task). In addition, cognitive function (global cognition, attention, executive function, processing speed, memory) will be assessed. Patients and healthy participants age 50+ will be additionally measured for fear of falling, history of falls, miniBESTest, functional reach on a force platform, timed up and go, and reactive balance. At Test 2, 7-10 days after Test 1, healthy adults young and age 50+ (n=40) will be re-tested for reliability of beam walking performance. All participants age 50+ will be re-called to report fear of falling and fall history 6 and 12 months after Test 1. Conclusion: The investigators expect to find that beam walking performance vis-à-vis the traditionally used balance outcomes predicts more accurately fall risks and falls.