In the Nagi model, disability is defined as?

• A. Loss of normal function at the organ level.
• B. Restriction in performing a socially defined role due to impairment.
• C. Environmental factors do not affect disability.
• D. The disease state.

Answer: (B)

Disability in the Nagi model is the restriction or inability to perform socially defined roles because of an impairment. It sits downstream of impairment and functional limitation, translating a health problem into real-life participation restrictions. For example, an impairment like joint pain and reduced range of motion can lead to functional limitations in daily tasks, which then prevents someone from fulfilling work or family roles, constituting disability. This differs from an impairment (loss of organ or body function) and from the disease state itself (the pathology). Environmental factors aren’t part of the original Nagi definition of disability, though other models later broaden the view to include context.