Previous mild traumatic brain injury and postural-control dynamics.

CONTEXT Postural control and cognitive function are adversely affected by acute mild traumatic brain injury (mTBI). Whether postural-control deficits persist beyond the acute stage in individuals with a history of mTBI is unclear. OBJECTIVE To determine if postural-control deficits persist in individuals with a history of mTBI. DESIGN Retrospective cross-sectional study. SETTING University research laboratory. PATIENTS OR OTHER PARTICIPANTS As part of an ongoing investigation examining cognitive and motor deficits associated with mTBI, 224 individuals participated in the study. Of these, 62 participants self-reported at least 1 previous physician-diagnosed mTBI. INTERVENTION(S) Postural control was assessed using the NeuroCom Sensory Organization Test (SOT) postural-assessment battery. MAIN OUTCOME MEASURE(S) The SOT postural assessment yields 4 indices of postural control: a composite balance score, a visual ratio score, a somatosensory score, and a vestibular score. Postural dynamics were also examined by calculating approximate entropy of center-of-pressure excursions in the anteroposterior and mediolateral axis for each test condition. RESULTS Minimal differences in the SOT indices were noted among individuals with and without a history of previous mTBI (P > .05). In the group with a history of mTBI, anteroposterior postural irregularity decreased as postural difficulty increased. In contrast, the group without a history of mTBI displayed increased postural irregularity in the mediolateral direction. CONCLUSIONS Individuals with a history of mTBI exhibited altered postural dynamics compared with individuals without a history of mTBI. These findings support the notion that changes in cerebral functioning that affect postural control may persist long after acute injury resolution.