Anosognosia and Denial of Deficits

Question 1

What is Anosognosia?

Answer 1

is a symptom of severe mental illness experienced by some that impairs a person’s ability to understand and perceive his or her illness

-The largest reason why people with schizophrenia or bipolar disorder refuse medications or do not seek treatment
-An inability or refusal to recognise a defect or disorder that is clinically evident

Question 2

Hemi-spatial Neglect patients

Answer 2

A well-known example of anosognosia is often found in hemi-spatial neglect patients.

-The condition is usually caused by a stroke to the right parietal lobe that causes disruption of attention and spatial awareness of the left side of space
-They often behave as if the left side of the world does not exist

Question 3

Seen in many conditions following brain damage:

Answer 3

Schizophrenia- lack of insight
Aphasia- language and speech

Question 4

Prosopagnosia?

Answer 4

inability to recognise faces

-Most typically associated with hemiplegia following a right-hemisphere (RH) brain damage

Question 5

Who first introduced the term anosognosia?

Answer 5

Joseph Babinski (1914) a French-Polish neurologist, introduced the term anosognosia to describe the patients’ denial of their own paralysis.

“I want to draw attention to a mental disorder that I had the opportunity to observe in cerebral hemiplegia, which consists in the fact that patients seem unaware of, or ignore the existence of, their paralysis”.

Question 6

Anton’s syndrome

Answer 6

Denial of loss of vision (visual anosognosia)
A rare disorder following bilateral occipital lobe damage

Anton’s syndrome is a manifestation of bilateral occipital lobe damage in cortically blind patients. These patients lack insight into their disease and deny their blindness. Classically, patients with this syndrome dismiss the diagnosis and confabulate visions

Question 7

Anosognosia for hemiplegia (AHP)

Answer 7

Refers to a syndrome in which a patient typically following a stroke, fails to recognise his motor deficit

Dissociates from neglect (although often co-exists with it)

Question 8

(Adair et al.,1997)
WADA Test

Answer 8

• Initially denied left hemiparesis
• 8 continued to deny it after viewing left hand (in right space, recognised hand as their own and identified number on hand)

Question 9

(Ramachandran, 1995)
Mirror Box Experiment

Answer 9

Patient’s left hand placed in box but views via a mirror an actor’s hand

-Asked to move it up and down
-Actors hand moves- her own hand does not
-Shows no surprise

Question 10

Brain areas associated with Neglect
(Vallar, 1998)

Answer 10

Brain areas associated with anosognosia are also associated with unilateral neglect

Neglect: usually posterior parietal damage

Hemianopia: loss of vision – damage to occipital lobe

Question 11

Anosognosia without Neglect
Single case study

Answer 11

-Areas 4, 6 and 44 (pars opercularis) - all known to be involved in programming motor acts, perception of action and interpreting actions of others (imitation, mirror neurons)
-Premotor cortex has a role in the conscious monitoring of motor acts
-Broca’s area in left hemisphere

Question 12

Caloric Stimulation

Answer 12

-A test that uses differences in temperature to diagnose damage to the acoustic nerve

• Two cases with frontal tumours who showed pseudohemianopsia (visual field defect- neglect)
• Problem looking and reaching to left
• Cold water in left ear – nystagmus eye movement
• Fast phase to right, slow sweep to left
• Improved reaching to left
• Recovery of extra personal neglect

Question 13

Caloric Stimulation & Anosognosia
(Ramachandran, 1995)

Answer 13

Case BM – stated left arm not paralysed and belonged to her son (somatoparaphrenia)

-Cold water in left ear (Caloric irrigation)
-BM- after caloric irrigation: acknowledged her arm had been paralysed for past three days effects lasted 30 minutes
-Shows memory consolidation for event
-8 hours later reverted to denial and when questioned remembered irrigation, but said both arms moved
-BM recalled caloric stimulation and various other details, but not that she had acknowledged her hemiplegia

Question 14

Summary: Anosognosia

Answer 14

-Not due to sensory loss, intellectual impairment alone
-Dissociates from neglect
-Linked to right hemisphere cortical and sub-cortical regions

Motor (area 4) and premotor cortex (area 6), parietal and prefrontal cortex
-Inferior frontal gyrus, insula
-Motor learning and inhibition, Involved in body self-awareness

Anosognosia is the most common in which two diagnoses:

• Bipolar disorder and Schizophrenia