Agnosia is a rare neurological disorder where a patient is unable to recognize and identify objects, sounds, or people despite having normal sensory functions. There are two main types - apperceptive agnosia caused by deficits in early perceptual processing, and associative agnosia where recognition fails despite intact perception. Agnosia most commonly affects the visual or auditory senses. It is caused by conditions like strokes, tumors, or injuries. Diagnosis involves examinations to rule out other cognitive issues, and management focuses on treatment of the underlying cause along with rehabilitation therapy.

1. A D E W I J A Y A , M D – M A R C H 2 0 2 0
AGNOSIA

2. Introduction
 Is a rare disorder whereby a patient is unable to
recognize and identify objects, persons, or sounds
using one or more of their senses despite otherwise
normally functioning senses
 The deficit cannot be explained by memory,
attention, language problems, or unfamiliarity to the
stimuli.
 Usually, one of the sensory modalities is affected
De Renzi E. [Agnosia]. Recenti Prog Med. 1989 Dec;80(12):633-7.

3. APPERCEPTIVE ASSOCIATIVE
Failure in recognition
due to deficits in the
early stages of
perceptual processing
A failure in recognition
despite no deficit in
perception.
Associative agnosia
patients can typically
draw, match or copy
objects while
apperceptive agnosia
patients cannot.
Agnosia
Coslett HB. Sensory Agnosias. In: Gottfried JA, editor. Neurobiology of Sensation and Reward. CRC Press/Taylor & Francis; Boca Raton (FL): 2011.
De Renzi E. [Agnosia]. Recenti Prog Med. 1989 Dec;80(12):633-7.

4. Visual
TactileAuditory
Kumar, A., & Wroten, M. (2019). Agnosia.

5. Visual Agnosia
 Prosopagnosia (face)
 Simultanagnosia (dorsal vs ventral)
 Color agnosia
 Topographical agnosia (spatial information)
 Finger agnosia
 Akineptosia (motion)
 Agnostic alexia (inability to recognize words visually)
Kumar, A., & Wroten, M. (2019). Agnosia.

6. Auditory Agnosia
 Phonagnosia
 Verbal auditory agnosia or pure word deafness
 Nonverbal auditory agnosia
 Amusia
Kumar, A., & Wroten, M. (2019). Agnosia.

7. Tactile agnosia
 Amorphognosia is the inability to identify the size
and shape of objects by touch, for example, a triangle
or square.
 Anosognosia is the inability to identify distinctive
qualities like texture and weight, for example, a piece
of wood, cotton or metal.
 Tactile asymbolia is impaired recognition by touch in
the absence of amorphognosia and ahylognosia
Kumar, A., & Wroten, M. (2019). Agnosia.

8. Etiology
 Strokes
 Tumors
 Infections
 Dementia
 Hypoxia
 Toxins such as carbon monoxide poisoning
 Head injury
 Developmental disorders
 Other neurological conditions
Kumar, A., & Wroten, M. (2019). Agnosia.

9. Epidemiology
 Very rare
 Less than 1 %
 Visual agnosis is the most common
De Renzi E. [Agnosia]. Recenti Prog Med. 1989 Dec;80(12):633-7.
Coslett HB. Sensory Agnosias. In: Gottfried JA, editor. Neurobiology of Sensation and Reward. CRC Press/Taylor & Francis; Boca Raton (FL): 2011.

10. Diagnosis
 History
 Physical examination
 Memory and cognitive testings
 Neuroimaging
Kumar, A., & Wroten, M. (2019). Agnosia.

11. Management
 Treat the underlying cause
 Rehabilitation, speech, and occupational therapy
 Alternative Cues and Strategies
 Organizational Strategies:
- Provide a predictable environment and consistency
- Declutter, for example, things patients use every day
should be kept out in one place
- Label everything
Burns MS. Clinical management of agnosia. Top Stroke Rehabil. 2004 Winter;11(1):1-9.
Heutink J, Indorf DL, Cordes C. The neuropsychological rehabilitation of visual agnosia and Balint's syndrome. Neuropsychol Rehabil. 2019 Dec;29(10):1489-1508.
Trivelli C, Turnbull OH, Sala SD. Recovery of object recognition in a case of simultanagnosia. Appl Neuropsychol. 1996 Aug-Nov;3(3-4):166-73.

12. Differential Diagnosis
 Dementia, aphasia, acute confusional states
(delirium), disturbance of attention, and
unfamiliarity with stimuli.
 Also, clinicians need to confirm make sure no actual
sensory impairment such as color blindness,
cataracts, hearing loss, neuropathy, among others
Kumar, A., & Wroten, M. (2019). Agnosia.

13. Prognosis
 Few patients with agnosia regain their sensory
function.
 Most recovery occurs within the first three months
and to a variable degree may continue up to a year.
 Prognosis depends on the patient's age, etiology,
type, size and location of the area affected, the extent
of impairment, effectiveness of therapy.
Kumar, A., & Wroten, M. (2019). Agnosia.

14. THANK YOU