"Head injury" or "traumatic head injury" means any insult to the brain not of a degenerative or congenital nature, but caused by an external physical force, that may produce a diminished or altered state of consciousness which results in impairment of cognitive abilities or physical functioning. It can also result in the disturbance of behavioral or emotional functioning. These impairments may be either temporary or permanent and cause partial or total functional disability or psychosocial maladjustment.