Balance and vestibular function.

Balance impairment is the most common motor symptom across the spectrum of severity of traumatic brain injury [1]. The severity of the balance dysfunction is dependent upon the extent and location of the injury to the brain and surrounding structures. The ability to maintain balance is determined by input from visual, vestibular, sematosensory, cognitive, and emotional systems, as well as the ability to organize information from these functions for the proper motor output. It is common to have multiple system involvement after traumatic brain injury due to the nature of the injury. In addition, balance may also be affected due to other injuries incurred during the initial traumatic event such as fractures or peripheral nerve injuries. Medications used to manage medical issues may also contribute to problems with balance and can delay recovery from the injury. Horak, Wrisley and Frank [2] developed a balance evaluation tool that organizes postural control systems in to six categories for diagnostic and treatment purposes: