Anticipatory and Compensatory Postural Responses during Perturbed Standing in Individuals with Traumatic Brain Injury.

Anticipatory postural adjustments (APA) and compensatory postural adjustments (CPA) are neuromuscular responses generated to stabilize the body and achieve balance during perturbations. The impaired sensory integration after a traumatic brain injury (TBI) can limit the ability to perceive perturbations and potentially affect the ability to generate APA and CPA responses. The main objective of this investigation is to explore the existence of APA and CPA generation in tibialis anterior (TA) and gastrocnemius (GAST) muscles during base of support perturbations in healthy controls (HC) as well as individuals with TBI. The secondary objective is to explore the effectiveness of a novel computerized biofeedback based intervention (CBBI) at improving APA and CPA responses in individuals with TBI. We observed that all three groups - HC (n=5), TBI-control (n=5), and TBI-Intervention (n=4) showed the presence of only CPA responses for the TA muscle, however, these responses were longer and variable for both TBI groups, compared to the short and consistent responses of the HC group. The GAST was involved in both APA and CPA for all groups. After the 4-week CBBI period, the TBI-I group showed increased APA responses for both TA and GAST. Further, the TBI-I group showed reduced CPA responses for both TA and GAST after the intervention. The elevated and longer CPA responses of TA and GAST and lower APA responses of GAST could suggest impaired postural control. Due to their significance and potential link to the balance dysfunction, these mechanisms need to be studied comprehensively in larger samples in order to effectively optimize the rehabilitation approaches for improving balance and avoiding falls in individuals with TBI.