Balance involves maintenance of a stable position at rest; stabilizing voluntary movement; and reacting to external movements. Good balance means making immediate postural adjustments that shift the center of gravity to the center of support. TBI can impair balance while sitting, standing or walking to a mild, moderate or severe extent on a temporary or permanent basis. When severe, imbalance can reduce a patient’s capacity to live alone and perform essential daily activities. Milder disturbances may limit sports, recreation and leisure. Patients with severe TBI almost always require balance and gait training during rehabilitation.