Nightly administration of a unique, sublingual (under the tongue) formulation of tizanidine, a known anti-spasticity medication, has been shown in a previous study to improve sleep and next-day functioning in CP (cerebral palsy) patients. It is hypothesized that this improvement in sleep efficiency (i.e.,fewer wake episodes, longer time asleep, etc.) with resulting improvement in quality-of-life (i.e.,improvements in next-day functioning, cognition and movement) may also be seen in a similar patient population, i.e., children with traumatic brain injury (TBI).