Tracking recovery of vestibular function in individuals with blast-induced head trauma using vestibular-visual-cognitive interaction tests.

Background And Purpose: Traumatic brain injury secondary to blast exposure is a significant international concern and a growing rehabilitation issue. Our objective was to determine whether a novel battery of vestibular-visual-cognitive interaction tests provides objective data to document functioning, and the changes in functioning associated with vestibular physical therapy (VPT) treatment, in individuals with blast-induced balance disorder.

Methods: Eighty-two individuals with blast-induced mild traumatic brain injury were evaluated at baseline using a set of vestibular-visual-cognitive tests. Testing was repeated at 4-week intervals after beginning VPT. The tests included static visual acuity, perception time, target acquisition, target following (TF), dynamic visual acuity (DVA), and gaze stabilization tests. The VPT program consisted of exercise procedures that targeted the vestibulo-ocular reflex, cervico-ocular reflex, and depth perception. Somatosensory balance exercises, dynamic gait, and aerobic function exercises were also included. Participants attended VPT twice weekly for 1-hour appointments and were instructed to perform the exercises at home on other days. Mean test values were determined and compared with normative values previously collected in our laboratory from individuals without vestibular dysfunction.

Results: Mean participant pre-VPT measures for perception time and target acquisition were similar to normative values, and there was no significant change in these measures. Initially, TF and DVA scores were below normative levels but returned to normative levels after 8 weeks of VPT. Gaze stabilization scores were below normative levels pre-VPT but improved by the time of the week 8 evaluation.

Conclusions: This battery of vestibular-visual-cognitive tests seems to be reasonable to establish initial status and to evaluate participant progress associated with participation in VPT. Our data suggest meaningful improvement in TF and DVA after 8 weeks of treatment. A treatment period of 12 weeks or longer may be required for gaze stabilization scores to return to normative values.