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.