Neurology and Neurosurgery/Agnosia

Definition of Generalized Agnosia

A defect in recognition, where a patient can generally sense objects and forms, but is unable to consciously recognize and interpret the meaning of the sensory input.

Apperceptive Agnosia

Agnosia characterised by recognition failure caused by impairment in visual perception. Patients are unable to recognize objects despite having normal acuity.

Associative Agnosia

A visual Agnosia characterised by the lack of meaning associated with percepts despite the patient being able to normally perceive an object and draw it.

Auditory Agnosia

Agnosia characterised by the inability to recognize sounds despite the patient having normal auditory functioning. Auditory Agnosia is typically associated with non-speech sounds. When agnosia involves speech, it is referred to as "pure word deafness"

Ideational Agnosia

Agnosia characterised by faulty recognition and interpretation of symbols.

Landmark Agnosia

Agnosia characterized by the inability to recognize stable objects in the environment. Patients can typically describe them in detail, but are unable to describe or recognize them.

Tactile Agnosia

Agnosia characterized by the inability to recognize and interpret objects by touch.

Visual Agnosia

Agnosia characterized by the inability to recognize and interpret objects in the visual field. Visual Agnosia may also sometimes be referred to as "Optic Agnosia".