In the Nagi disability model, pathology is defined as which?

• A. Occurs at the cellular level and interferes with the body's normal processes.
• B. Loss or abnormality at the tissue or organ level.
• C. Inability to perform a task due to impairment.
• D. Inability to perform activities at the whole-person level.

Answer: (A)

Pathology in the Nagi model is the disease process at the cellular level that disrupts normal body processes. It’s the first level of change—the underlying cellular or tissue abnormalities that set the stage for later functional problems. The option describing events at the cellular level interfering with normal processes best captures this idea. By contrast, impairment refers to a loss or abnormality in body structure or function, functional limitation to the task level due to impairment, and disability to the whole-person level of inability to perform socially defined activities.