A traumatic brain injury (TBI) is often caused by an external force such as an impact to the head. It can range in severity and clinical features depending on the location of the injury. Common causes of TBIs include motor vehicle collisions, falls and violence. TBIs can result in physical, cognitive, emotional, social and behavioural changes that negatively impact a client's functional ability and limit occupational performance. No two head injury cases are the same. Occupational therapists often provide therapy treatment programs individually and tailor them to a client's needs. For example, rehabilitation may help correct inappropriate behaviours exhibited in work or home environments. Client's are evaluated using specific assessments to determine what actions are appropriate. In contrast to individual therapy treatments, an occupational therapist may run group therapy sessions for self-regulation or stress reduction. Other examples include: -provide support to maintain the ability to complete key job tasks in the workplace -help adjust and accommodate for re-entry into the community -assist clients and families with personal problems at home such as behavioural challenges, including angry or non-cooperative emotions -support the use of assistive devices and vocational rehabilitation -use a cognitive strategy called errorless learning for people with memory impairments. With errorless learning, a client learns something by doing it and does not make a mistake as he/she/they learn information or procedures Ghajar, J. (2000). Traumatic brain injury. The Lancet, 356(9233), 923-929.