Definition

Noun: A neurological disorder characterized by the inability to recognize or interpret sensory information (such as objects, sounds, or shapes) despite normally functioning senses (like vision, hearing, or touch). It is a deficit in higher-level perceptual processing.

Usage

Agnosia is a medical and psychological term. It is typically used in clinical, neurological, and academic contexts to describe a specific cognitive impairment. It is often modified by a word specifying the affected sensory modality (e.g., visual agnosia, auditory agnosia).

Examples

• The patient's visual agnosia meant she could see a key perfectly well but could not identify it as a key.
• After the stroke, he developed prosopagnosia, a type of agnosia for faces.
• The neurologist diagnosed the condition as tactile agnosia because the man could feel a coin in his hand but could not name it by touch alone.

Advanced Usage

• Associative Agnosia: A subtype where a person can perceive the shape and features of an object but cannot access its meaning or name.
  • Example: In associative visual agnosia, a patient might accurately draw a picture of a hammer but have no idea what it is used for.
• Apperceptive Agnosia: A subtype where a person cannot form a coherent perceptual whole from sensory input.
  • Example: A person with apperceptive visual agnosia might see lines and curves but be unable to recognize them as forming a letter.

Variants and Related Words

• Prosopagnosia (n): A specific type of visual agnosia involving the inability to recognize familiar faces.
• Agnosic (adj): Relating to or suffering from agnosia.
  • Example: The agnosic patient underwent extensive cognitive testing.

Synonyms

• Recognition deficit
• Perceptual disorder (Note: This is a broader term; agnosia is a specific type of perceptual disorder.)

Related Phrases and Terms

• Neurological deficit: A broader term for any impairment of nervous system function, which includes agnosia.
• Cognitive impairment: A general term for decreased mental function, of which agnosia is one possible manifestation.

Noun

1. inability to recognize objects by use of the senses