Aphasia is best defined as:

• A. An acquired language disorder due to a neurological cause that affects receptive and expressive language across modalities and does not result from sensory, psychiatric, or intellectual disorder.
• B. A temporary confusion state due to metabolic disturbances.
• C. A motor speech disorder limited to articulation without language comprehension issues.
• D. A transient cognitive impairment due to sleep deprivation.

Answer: (A)

Aphasia arises from brain injury that disrupts language networks in the left hemisphere, leading to problems with understanding and producing language across multiple forms. It is acquired, not developmental, and its core feature is a deficit in language—affecting speaking, comprehension, reading, and writing—rather than a generic cognitive or sensory problem. It is not caused by metabolic issues, sleep deprivation, or psychiatric illness, and it is distinct from motor speech disorders that limit articulation. This combination of acquired neurological origin and widespread language impairment across modalities is why this description best defines aphasia.