Patients who completed the 12-week double blind protocol may enter this 26-week, open-label extension. This extension will give patients who complete the study an opportunity to receive treatment with open-label rivastigmine 3-12 mg/day and further evaluation for the cognitive deficits related to traumatic brain injury. This extension will enable further evaluation of patients, as well as analyses to be conducted examining response to treatments in the original drug and placebo groups.