A computer implemented system and method for performing a quantitative balance assessment on a subject are described. The method comprises instructing the subject to perform an assessment task with at least a first kinematic sensor mounted on the subject's head; collecting kinematic sensor measurements, comparing the measurements to a threshold value; summing the total number of kinematic sensor measurements that exceed the threshold value to generate a numerical score indicative of the subject's postural stability. The system makes use of only kinematic data collected from the wireless sensors to quantify BESS, and generate a BESS score, without any other physiological variables such as forward sway.