According to many definitions, a disability is an impairment that may be cognitive, developmental, intellectual, mental, physical, sensory, or some combination of these. Other definitions describe disability as the societal disadvantage arising from such impairments. Disability substantially affects a person’s life activities and may be present from birth or occur during a person’s lifetime.Disabilities is an umbrella term, covering impairments, activity limitations, and participation restrictions. An impairment is a problem in body function or structure; an activity limitation is a difficulty encountered by an individual in executing a task or action; while a participation restriction is a problem experienced by an individual in involvement in life situations. Disability is thus not just a health problem. It is a complex phenomenon, reflecting the interaction between features of a person’s body and features of the society in which he or she lives.