M6, T2, cognitive neuropsychology and delusions about the self

Question 1

Mirrored-self misidentification, patient FE example, big details

Answer 1

• Patient FE (Breen et al., 2000) 87 year old male
• Brief hospitalisation for temporary stroke
• After discharge occasional nocturnal hallucinations
• 12 months after when they moved house
  -> FE could not recognise his own reflection in the mirror
  -> FE thought that his reflection was someone else following him around
  -> Occurred in various places not just at home
• Tried to talk to this person and was not sure why the person did not speak back to him
• Not paranoid about the person nor did he believe the person had harmful intentions

Question 2

FE problem hemispheres and following years

Answer 2

• FE’s family tried to explain the problems with his belief
• FE listened and often agreed with them BUT, delusion persisted
• Left hemisphere functions OK -> language and verbal memory
• Right hemisphere functions impaired -> copying, drawing, visual memory
• Delusion continued for about 3 years
• FE’s cognitive function declined over 2-year follow-up period
• Finally diagnosed with dementia (uncertain aetiology)

Question 3

FE perspective of the mirror

Answer 3

• Did not have mirror agnosia, semantic knowledge mirrors intact
• Object identification of mirrors OK too
• Used mirror to shave but this was an automatic behaviour (not really looking)
• Covert behavioural evidence that is was himself in the mirror
  -> Asked if the person was bald he tilted his own head to be visible in the mirror image
• FE oriented to self, no depersonalisation
• Always the person in mirror, never a double or imposter
• Good at identifying his own things

Question 4

FE face recognition

Answer 4

• FE did have some deficits in face recognition for famous faces
  -> Did have semantic knowledge of these people
• FE good at face recognition of family members including himself
• Months after delusion onset FE developed another delusion
  -> Wife was 2 people and his son had a brother (he had son and daughter)
• General intellectual function occurred after this so no further investigation possible

Question 5

FE mirrored-self misidentification explanation via Coltheart (2007, 2010, 2011) Two Factor Theory

Answer 5

1. Patient some impairment of face recognition (first factor/deficit)
2. Right hemisphere damage or impaired function in frontal region [Right lateral prefrontal cortex] = weakened belief evaluation system (second factor/deficit)

Question 6

Reverse intermetamorphosis patient example, RZ

Answer 6

• Patient RZ (Breen et al. 2000), 40 year old woman who believed she was her father or grandfather
• Only responded to father’s name, gave his history, was his age etc.
• Schizophrenia at 23 but was well until 12 months before hospitalisation
• When looking at herself in the mirror reported seeing her father
• Reported physical characteristics that were consistent with seeing her father

Question 7

Explanation of Reverse Intermetamorphosis via Coltheart (2007, 2010, 2011) Two Factory Theory

Answer 7

1. Patient deluded about who she was perhaps due to physical changes (first factor/deficit)
2. Right hemisphere damage or impaired function in frontal region [Right lateral prefrontal cortex] = weakened belief evaluation system (second factor/deficit)

Question 8

Somatoparaphrenia, patient examples

Answer 8

• Two patients with anosognosia for motor and somatosensory neurological deficits had delusions for ownership of their left limbs (Gerstmann, 1942)
• Patient’s delusions for the side of their body contralateral to brain damage
• Brain damage -> paralysis on contralateral side of body
• Body parts belong to someone else
• Deny ownership of body parts
• Frontal lobe damage associated with right hemisphere damage

Question 9

Somatoparaphrenia. cooccurring deficits

Answer 9

• Assessed by verbal interview
• Might be sensory motor deficit or not
• May have visual field deficit or not
• Can recognise their own objects on the disowned limbs
• May improve if disowned limb is moved to attended right hand side of space
• May co-occur with unilateral spatial neglect
• Delusion due to limb paralysis and damage to right frontal region

Question 10

Somatoparaphrenia via Colthearts Two Factor Theory

Answer 10

1. Paralysis in limb creates disconnection from the body, therefore not mine (first factor/deficit)
2. Right hemisphere damage or impaired function in frontal region [Right lateral prefrontal cortex] = weakened belief evaluation system (second factor/deficit)

Question 11

Delusion of alien control, action execution

Answer 11

• Construct a motor program to execute
• During action get sensory feedback about movement
• Usually movement and feedback match

Question 12

Delusion of alien control, impaired self-monitoring

Answer 12

• expected feedback not understood OR
• expected feedback not generated OR
• comparison of movement and feedback didn’t happen

Question 13

Delusion of alien control, Coltheart Two Factor Theory

Answer 13

1. Impaired self-monitoring action and sensory feedback link (first factor/deficit)
   -> Not all cases lead to delusion of Alien control (Foruneret et al 2002)
2. Impaired right frontal lobe function [Right lateral prefrontal cortex] -> weakens belief evaluation system (second factor/deficit)