Trunk sway measures of postural stability during clinical balance tests: effects of age

The major disadvantage of current clinical tests that screen for balance disorders is a reliance on an examiner's subjective assessment of equilibrium control. To overcome this disadvantage we investigated, using quantified measures of trunk sway, age-related differences of normal subjects for commonly used clinical balance tests. Three age groups were tested: young (15-25 years; n = 48), middle-aged (45-55 years; n = 50) and elderly (65-75 years; n = 49). Each subject performed a series of fourteen tasks similar to those included in the Tinetti and Clinical Test of Sensory Interaction in Balance protocols. The test battery comprised stance and gait tasks performed under normal, altered visual (eyes closed), and altered proprioceptive (foam support surface) conditions. Quantification of trunk sway was performed using a system that measured trunk angular velocity and position in the roll (lateral) and pitch (fore-aft) planes at the level of the lower back. Ranges of sway amplitude and velocity were examined for age-differences with ANOVA techniques. A comparison between age groups showed several differences. Elderly subjects were distinguished from both middle-aged and young subjects by the range of trunk angular sway and angular velocity because both were greater in roll and pitch planes for stance and stance-related tasks (tandem walking). The most significant age group differences (F = 30, p