Case 3 - The Man who Fell Out of Bed

Question 1

What is anosognosia?

Answer 1

The lack of awareness or denial of a disability resulting from brain injury, e.g., loss of recognition or awareness of hemiplegia

Question 2

What is asomatognosia?

Answer 2

The inability to recognise the affected limb as one’s own, e.g., manifested by deletions or additions in body image due to a lesion in the parietal lobe

Question 3

Hemiparesis:

Answer 3

Muscle weakness on one side of the body

Question 4

Hemiplegia

Answer 4

Complete paralysis of one side of the body

Question 5

Somatoparaphrenia

Answer 5

Rejecting body parts as someone else’s

Question 6

Misoplegia

Answer 6

Hatred of a paralysed limb

Question 7

Body Integrity Identity Disorder

Answer 7

A condition where individuals desire elective amputation or paralysis of a specific limb, e.g., Historical case of an Englishman requesting leg removal against his will

Question 8

Xenomelia / “Foreign Limb Syndrome”

Answer 8

Non-acceptance of one’s own limb(s) leading to a desire for elective limb amputation or paralysis

Question 9

What are the components of the Zurich Xenomelia Scale?

Answer 9

Pure amputation desire; erotic attraction involving amputation; pretending behaviour related to amputation

Question 10

Apotemnophilia

Answer 10

Intense desire for amputation of a specific limb.

Question 11

Body dysmorphia

Answer 11

Excessive worry about a perceived defect in a body part.

Question 12

What are the two classes of explanation for ownership?

Answer 12

Prediction of outcome: reason for the inability to tickle oneself, involving the anticipation of self-produced actions.
Multisensory: involves correlating sensory inputs, matching visual, tactile and proprioceptive signals

Question 13

Sense of Body and Sense of Action in Self-Recognition

Answer 13

The role of movement in recognising one’s body and the connection between intentions and movements. For example, anticipation of events resulting from intended actions contributing to self-recognition.

Question 14

What happened in the Van den Bos et al., 2002 study?

Answer 14

Participants wearing identical gloves asked to indicate which hand was their own after each trial with various rotations. Results indicated that there were errors related to spatial matching and movement, emphasising the role of both cues in self-recognition.

Question 15

Anosognosia Brain Lesion Study (Karnarth et al., 2005)

Answer 15

Lesion subtraction analysis between groups with and without anosognosia for hemiplegia. Results showed that posterior insula was 62% more affected in anosognosia group, suggesting a role in the condition.

Question 16

Anosognosia (AHP):

Answer 16

Sub-type: AHP (Anosognosia for Hemiplegia).
Hemisphere: Right hemisphere (though Cocchini et al., 2009, presents an alternative view).
Prognosis: Generally poorer prognosis than patients without AHP.
Characteristics: Inability to dissociate verbally and behaviorally; may admit a problem but still attempt corresponding actions.
Treatment: Currently, no established treatment for AHP.

Question 17

Motor Awareness:

Answer 17

Evidence of Intact Intentions: Fotopoulou et al., 2008, study providing false feedback about movement, suggesting a role of intentions in generating illusory movements.
Motor Comparator Explanation: Video feedback resolving anosognosia, where patients reported awareness of deficits after viewing footage from a third-person perspective.

Question 18

Rubber Hand Illusion (RHI):

Answer 18

Experiment 1: Participants’ hidden hand and a rubber hand stroked synchronously, inducing a sense of ownership over the rubber hand.
Experiment 2: Testing proprioception through a “proprioceptive drift” after asynchronous and synchronous stroking.
Importance of Synchrony: Synchronized vision and touch essential for generating self-reported ownership.

Question 19

Skin Conductance Response (SCR):

Answer 19

Definition: Measure of the resistance of the skin, indicating autonomic nervous system arousal.
Armel and Ramachandran (2003) Study: SCR measured during the Rubber Hand Illusion, showing higher intensity for synchronous stimulation.

Question 20

Correlational Mechanism:

Answer 20

Bayesian Perceptual Learning: Modalities are ‘bound’ when co-occurring with high probability, such as the correlation between seen and felt touch during the Rubber Hand Illusion.

Question 21

Brain Activity and Ownership:

Answer 21

Parietal and Ventral Pre-motor Areas: Neurons code seen and felt arm position, potentially contributing to the conscious experience of ownership.
Ehrsson et al., 2004: Study involving brain activity during the Rubber Hand Illusion, suggesting involvement of premotor areas.

Question 22

BIID (Body Integrity Identity Disorder):

Answer 22

Desire for Amputation: Three times more common for the left leg than the right.
Similarity to Somatoparaphrenia: Patients can trace a precise line on the limb along which amputation is desired.
Aversive Ownership: Some patients find ownership of the limb to be vaguely aversive.

Question 23

Spatial-Temporal Integration of Touch:

Answer 23

Sensitivity and Bias: Measures in a temporal judgment task revealing attention toward the affected body part in individuals desiring leg amputation.

Question 24

Limb Apparent Motion Perception:

Answer 24

Effect of Posture: HC and amputees more likely to judge impossible movement as possible when leg bound or prosthesis absent.
BID: No effect of current body posture, as if the limb is always absent.

Question 25

Multisensory (MSI) Account of BIID:

Answer 25

Explanation: Somatosensory input is intact, but the body image is missing the limb, leading to aversion and a desire for amputation.

Question 26

Structural Changes in Right IPL:

Answer 26

Participants: Males desiring above-knee amputation.
Changes: Structural changes in the right anterior insula correlated with the strength of amputation desire.

Question 27

Multisensory Explanation Application:

Answer 27

Application: Multisensory illusions/virtual reality showing the affected limb has disappeared provide transient reduction in BIID symptoms.

Question 28

Possible Causes of Change in BIID:

Answer 28

Brain Changes: Suggest early developmental changes.
Somatic Hypervigilance: Excessive attention exacerbates the alien feeling attached to the target limb.
Conflict Between Representations: Conflict between online and offline (desired) body representation.

Question 29

Broader View:

Answer 29

Importance of Interacting: Emphasizes the importance of interacting with others, such as amputees during childhood.