Balance abilities in individuals with moderate and severe traumatic brain injury.

Balance characteristics, latency, amplitude, and symmetry were measured in 23 moderate and 23 severe traumatic brain-injured (TBI) patients. Patients received two graded forward and two graded backward linear perturbations. Although within normal limits, latency was high. Patients were able to appropriately grade force in relation to the size of the perturbation. Standing posture prior to and during perturbation was recorded by the amount of force generation through each lower extremity. Some individuals used an asymmetrical balance response following perturbations, whereas others shifted to a more symmetrical weight-bearing balance response. TBI patients may be prone to instability due to a combination of long latency of onset of the balance response coupled with asymmetrical stance patterns during recovery from an unexpected linear perturbation.