Inclusion Criteria:

• Traumatic brain injury confirmed by available brain imaging (CT or MRI) and be at least 52 weeks post injury
• Neuropsychologic disturbances indicated by: impaired memory (reduction of below 1 standard deviation (SD) of the mean on the California Verbal Learning Test (CVLT) and impaired executive function (reduction of below 1 standard deviation (SD) of the mean on the Verbal Memory Learning Test (VLMT) and Tower of London Test (ToL) and impaired attention (reduction of below 1 standard deviation (SD) of the mean on the Test Battery for Attentional Performance (TAP)
• Be required to have had sufficient education to read, write, and effectively communicate
• Be cooperative, able to ingest oral medication, and able to complete all aspects of the study and capable of doing so, either alone or with the aid of a responsible caregiver according to the investigator's judgement

Exclusion Criteria:

• A current diagnosis of cerebrovascular disease, any primary neurodegenerative disorder, or any other causes of neuropsychologic disturbances
• A current diagnosis of active, uncontrolled seizure disorder or major depression, or any other diagnosis that may interfere with the patient's response to study medication
• An advanced, severe or unstable disease of any type that may interfere with efficacy evaluations
• Female patients with child-bearing potential who are breast-feeding, pregnant or not practicing non-hormonal contraception

Other protocol-defined inclusion/exclusion criteria may apply.