W8 - Anosognosia for Motor Impairments

Question 1

What is anosognosia? =

Answer 1

1. A patient lack of knowledge of their illness or impairment
   Gnosia = knowledge, noso = impairment, a = negative prefix, thus it means having no knowledge of your impairment

Types include visual, memory and cognitive anosognosia = no knowledge that you are blind, have limited memory or cognition

Focus: anosognosia for left side motor impairments on left limb following a RH stroke

Question 2

How is anosognosia assessed?

Answer 2

1. In a structured interview, beginning with general questions about health and what happened (stroke)
2. moving towards more specific questions about the impairment, and whether you can move your left arm
   Why are you here?What happened?Any problems on the left side of your body?

Question 3

Interview assessment: What are the 3 levels of severity of Bisiach Anosognosia Scale?

binary classification groups 0-1 and 2-3

With leg limb issues, can you classify people with scores from 0 to 6

Answer 3

0 (no anosognosia) = can spontaneously report or mentioned by patient when asked about any general complaints

1 (mild) - disorder is reported only after a specific question about the strength of limb

2 (moderate) - disorder is acknowledged only after its demonstration of routine techniques of neurological examination, eg., “Can you lift both hands in the air?”

3 (severe) - no acknowledgement of the disorder can be obtained

Question 4

NEW, more used now: What are the 0-2 levels of severity in anosognosia in the Berti Anosognosia Interview?

Answer 4

Begin with general questions and narrow to abilities of the arm/leg
If patients say they can move their left arm, then ask them to reach out and touch your hand, “Have you done it?” “Are you sure?”

0 - None, patient answered correctly to the first group of questions

1 - Mild, patient acknowledges they had a stroke, but denied their arm limb impairment, but then acknowledged that they cant reach

2 - Severe, patient still claims that they had reached examiners hand, that is is moving

Question 5

What are Illusory limb movements?

What patients should be prioritised?

Answer 5

the perceptual experience that their arm is moving

Entry point to study anosognosia is to find patients with severe types

Question 6

Three Kinds of Knowledge that might be Lacking in anosognosia?

These 3 kinds of knowledge are distinct as you can find double dissociations between them

Answer 6

1. Lacking knowledge of movement failure AT THE TIME it occurs - that you failed to move at the very time you did fail to move
2. Lacking knowledge of THE IDEA OF MOTOR IMPAIRMENTS THEMSELVES themselves - seem to not know that they can’t move their arm as a possibility, so they say they can
3. Lacking knowledge of the CONSEQUENCES OF MOTOR IMPAIRMENTS for everyday activities, you do not know that you can’t do all of these bimanual things that require 2 hands, eg., shoelace tying, clapping, opening a jar, carrying a tray

Question 7

In knowledge failure 1 - lacking knowledge of movement failure AT THE TIME it occurs - what is the role of belief updating and memory?

Answer 7

1. Belief update - If you have knowledge of movement failure at the time it occurs, you will automatically update the long held belief that your arm can move, thus knowledge of motor impairments
2. Lack of memory - Unless you have the knowledge but can’t remember it, thus the updated system will be forgotten, and can develop anosognosia

Question 8

How does damage to motor system play a role in lacking knowledge of movement failure AT THE TIME it occurs?

Answer 8

Damage to the motor control system can result in the absence of any experience of movement failure

or even the illusory experience of moving when they are not

Question 9

Blakemore, 2002: What do the ‘comparators’ do in the predictive processing model of motor movements?

Answer 9

1. The circles with X are called ‘comparators’ which compare the actual state of the arm to the predicted state of movement predicted by the motor control system
2. If the predictions between actual and predicted state movement do not match, a predictor error occurs
3. When comparators detect a PE, they generate a PE signal that is sent to unconscious processing, telling the brain to alter the expectation, or consciously, allowing an individual to perceive that their ar is not working

Question 10

What were the findings in Marcel (2004) - who asked:

“Currently, do you have any problems with eating, washing, tying a knot?”

“In your present state, how well, compared with normally, can you tie a knot, open a jar, ride a bike?”

Answer 10

Out of 44 patients:

1. 22/42 overestimated ability to do daily living activities
2. 24/42 overestimated ability to do bimanual tasks
3. 12/24 failed to acknowledge the motor impairment itself

Question 11

What were the main 2 implications found in the Marcel study?

Answer 11

1. 30/42 patients acknowledged they couldn’t move their arm, but had NOT UPDATED their beliefs about the consequences of their motor impairment
2. Thus there are less patients lacking knowledge of motor impairments and double number of patients who lack knowledge of the consequences their motor impairments in everyday activities

Question 12

What 2 examples show evidence of double dissociations in the 3 areas of knowledge for anosognosia?

Answer 12

1. Anosognosia for consequences lasts longer than anosognosia for the impairment itself (eg., Marcel study), overestimate bimanual task ability while admitting you cant move your arm
2. Or anosognosia for motor impairment could last longer than anosognosia for the consequences, whereby a patient could acknowledge they have many bimanual difficulties in everyday life, but haven’t made the inference that is is caused by their arm impairment

Question 13

How could anosognosia be considered a delusion?

Answer 13

It is a “fixed belief” that they can still move their left limb, that is “not amenable to change in the light of conflicting evidence” - DSM-5

Question 14

What other delusional condition is sometimes associated with anosognosia?

Answer 14

somatoparaphrenia - where they deny that their left limb is theirs

Question 15

What distinguishes anosognosia from other delusions?

Answer 15

1. All other delusions are a new-belief and exotic delusion, they report something abnormal has occurred despite the fact that everything is normal, ie., they are not dead, their partner is not an imposter - they have incorrectly updated their belief systems
2. In anosognosia, the delusion is a CONTINUED and commonplace belief

• but something abnormal has occurred, ie., arm stopped working,
• Held onto the long-lasting and normal belief that you could move your arm, and failure to update the new reality

Question 16

What kind of error of belief updating has occurred in anosognosia vs other delusions?

Answer 16

Others = It is a distinction between error of commission (changed beliefs wrongly)

Anosognosia = an error of omission (failed to change beliefs), asks Is anosognosia the only continued belief delusion?

Question 17

Why does the 2-Factor Account of Anosognosia as a delusion solely use the second step of the 2-Factor Theory of Delusions?

Answer 17

In anosognosia the delusional idea stems from the fact that this belief has been true until the brain injury

there is no need to postulate a neuropsychological impairment that will prompt this delusional idea, as the delusional idea “i can move my arm” has always been there

Thus - anosognosia is a continued belief delusion as they believed they can move their arm for many decades

Question 18

What is the 2-Factor Account of Anosognosia with the second step of the 2-Factor Theory of delusions (belief evaluation)

Answer 18

Anosognosia = it is believed that it can be explained via 2 factors:

1. The belief has been maintained from an anomaly of experience
2. The belief has been maintained from a failure of belief evaluation

Question 19

What are some candidates / potential explanations for the factor 1: anomaly of experience in anosognosia?

All are impairments in the motor control system take away the bodily experience that is telling you that you can’t move your arm

Answer 19

3 aspects of the motor control system:

1. Motor Intention deficit
2. Impaired proprioceptive feedback
3. Damage to/abnormal functioning of a comparator to detect mismatches between actual/estimated state of movement

Question 20

In 2-Factor Step of Anosognosia, in factor 1 anomalous experience, what is Theory 1 motor intention deficit?

Answer 20

1. When you try to move, a motor program is constructed, resulting in a motor command and then normally a subsequent movement
2. Motor program is also used to predict where the arm is going to move via the predictors, there is a predicted state and a desired state of movement “I predict it will move here and I want it to move here”
3. In anosognosia, despite wanting to move their arm, it is thought that the motor program is NOT constructed, predicted movement is NOT generated, and THUS PREDICTED STATE IS ARM WILL BE STILL
4. When the arm ends up not moving, you do NOT PERCEIVE A MISMATCH between predicted and actual state of movement, and thus you don’t experience your failure to move because the predicted state did not predict that the arm would move

Question 21

What is wrong with factor 1 anomalous experience, what is Theory 1 motor intention deficit?

Answer 21

evidence shows patients are generating motor programmes for movement despite being unable to move

Question 22

In 2-Factor Step of Anosognosia, in factor 1 anomalous experience, what is Theory 2 impaired proprioceptive feedback?

Answer 22

1. Motor control system does NOT GET FEEDBACK that the arm has NOT moved (via a proprioceptive signal telling you haven’t moved)
2. If there is no signal about the arm’s location, there is no ability to compare the estimated state of movement to the actual state, so there is no detection of a mismatch, no experience of failing to move

Question 23

In 2-Factor Step of Anosognosia, in factor 1 anomalous experience, what is Theory 3 Damage to/abnormal functioning of a comparator?

Answer 23

1. The system meant to detect the mismatches between actual/estimated state of movement is damaged, so again there is no mismatch signal, no experience of failing to move

Could be that the motor controls system is a very noisy system after a stroke, so the threshold for a signal needs to be higher, simply harder to receive a mismatch signal

Question 24

What are the 2 other candidates/theories for anomaly of experience in stage 1 of two-factor theory of anosognosia?

Answer 24

1 Loss of proprioceptive experience (no knowledge of where your arm is)

2. unilateral visuospatial neglect (no attention on the left side of the body)

Question 25

Why is neglect a candidate for anomaly of experience in two-factor theory of anosognosia?

Answer 25

1. Anosognosia persisting after 3 months after a stroke is almost always accompanied with neglect 2. Vocat (2010) found patients with severe proprioceptive loss and severe neglect in first 12 days of a right hemispheric stroke were found to be significantly more likely to have anosognosia

Question 26

Why do we need a second factor (within 2nd step of delusion theory) to explain the cause of anosognosia? “It feels like [my arm] is rising, but its NOT”

Answer 26

1. There are patients with the 1st factor who do not have anosognosia 2. Even without immediate experience of movement failure, other evidence of motor impairments is available "they ignore the wealth of evidence that they are paralysed, despite accidents, new disabilities, others feedback, thus the adherence of the delusional belief requires the postulation of another factor”

Question 27

What are Second factor candidates for 'failure of belief evaluation' in 2nd step of anosognosia?

Answer 27

1. The inability to remember the evidence 2. The inability to recognise that this evidence requires to reevaluate your current belief systems 3. The inability to carry out the task of belief evaluation (even if you can remember evidence and understand you should update your beliefs, you cannot do it as it is too cognitively demanding)

Question 28

What does 'failure of belief evaluation' in 2nd step of anosognosia? - The inability to remember the evidence entail?

Answer 28

results in an inability to reject the false belief that you can move your arm if you keep forgetting the evidence Patient NS eg., left side paralysis and unilateral neglect, and anterograde amnesia for self-related information (couldn’t remember things since the accident) His amnesia prevented him to use evidence to update his beliefs about his injury

Question 29

What test was used to evaluate INABILITY TO UPDATE CURRENT BELIEFS? in 'failure of belief evaluation' in 2nd step?

Answer 29

VOCAT (2013) used a Riddle Task that required patients to guess 10 words 1. For each target word, you get 5 clues, each one is successively more informative than the last 2. The first clue is a bit ambiguous, the last one leaves no doubt about the correct answer 3. Patients have to guess word and indicate their level of confidence 4. None of these target words were related to anything to do with their motor abilities Implications proposed that the impairments to belief updating in anosognosia stemmed from problems with mismatch/error detections - which detect an incongruence between the clue/evidence and the patient’s guess/belief No general problem of reasoning, but require more evidence and gave repeated number of errors with a larger incongruence between a new clue and guess, in order to find a new solution”

Question 29

What were the finding's in the Vocat 2010 study of INABILITY TO UPDATE CURRENT BELIEFS in Riddle Task?

Answer 29

1. Patients with anosognosia gave significantly higher confidence ratings than patients without anosognosia, at the 1st, 2nd or 3rd clue 2. As if the anosognosic's could not experience doubt anymore” (Vocat) 3. Showing impaired belief evaluation, a belief can be demoted to a hypothesis before evaluating it 4. More repetitive guesses: Patients with anosognosia were more than 2x as likely than controls to produce the same incorrect guess in response to 2 consecutive clues in the riddle 5. Performed equally well at reaching the end answer, but were less good at taking on board evidence that counted against their guesses

Question 30

What were the implications of Vocat's riddle task regarding belief evaluation and updating?

Answer 30

1. The impairments to belief updating in anosognosia stemmed from problems with mismatch/error detections - which detect an incongruence between the clue/evidence and the patient’s guess/belief 2. No general problem of reasoning, but require more evidence and gave repeated number of errors with a larger incongruence between a new clue and guess, in order to find a new solution

Question 30

What is the D-KEFS word context test? What does it test?

Answer 30

1. D-KEFS word context test within the battery of tests (Delis-Kaplan Executive Function System) 2. Word context test = asked to find the meaning of a mystery/foreign word based on clues given in sentences, and given 5 clues progressively more informative: "Many people eat 'sevs'" "A 'sev' a day keeps the doctor away" 3. evaluates deductive reasoning, information integration, hypothesis testing and flexible thinking

Question 31

What did Keil et al., 2005 find in frontal damaged patients using the foreign word D-KEFS Word Context Test?

Answer 31

1. with healthy controls and patients with frontal lobe damage (executive impairments) 2. The frontal damaged patients showed more random and seemingly disconnected guesses that did not seem to integrate the previous clues into their future guesses 3. Frontal damaged patients also show repetition of an incorrect answer like the anosognosic's

Question 32

What does 'failure of belief evaluation' in 2nd step of anosognosia? - The inability to carry out the task of belief evaluation entail?

Answer 32

1. Belief evaluation requires assessment of hypothesis in light of plausibility and evidence 2. the evidence might not point in the same direction, ie., people telling you you’re paralysed, and you experiencing illusory limb movements 3. Requires you to weight things up and hold all the evidence in mind

Question 33

What does Crosson belief about ability to do belief evaluation?

Answer 33

1. Crosson (1989) - noted that the transition from concrete pieces of evidence about specific difficulties to a more abstract/general belief about accepting you have a motor impairment is incredibly challenging Need a considerable amount of understanding to find the common thread between specific difficulties that you face

Question 34

What brain regions are implicated in impaired belief evaluation (2nd of 2nd step)

Answer 34

It is proposed that the second factor in anosognosia for motor impairments may involve impairments of executive function or working memory

Question 35

What is Anne's evidence (Aimola, 1999) between neglect and anosognosia?

Answer 35

In unilateral neglect patients 3 months after a stroke, Anne found 5 patients had anosognosia for motor impairments, while 4 did not Included 15 scores from neuropsych tests of visuospatial function attention memory, executive function and working memory Only 3/15 test scores were significantly predicted by overall anosognosia scores (0-6) for upper and lower limbs)

Question 36

What 3 test scores predicted anosognosia scores?

Answer 36

1. Elevator Counting with Distraction subtest of Everyday Attention, testing working memory, inhibition component/cognitive control 2. Categories Achieved 3. Perseverative Errors from the Wisconsin Card Sorting Test (WCST), assessing abstract reasoning ability, shifting cognitive strategies to changing environments, very similar to belief evaluation

Question 37

What does the Wisconsin Card Sorting Test (WCST) involve?

Answer 37

1. 4 stimulus cards with different colours and patterns 2. 128 response cards are sorted by placing each response card with one of the 4 stimulus cards 3. Get feedback by examiner about card placing onto stimulus card is right/wrong 3. Correct card placement = if the response card matches the stimulus card in alignment with the sorting rule, eg., sort by shape

Question 38

How is WCST similar to updating beliefs?

Answer 38

1. The sorting rules are figured out by listening to the examiners feedback about what is right and wrong 2. Could be an ambiguity, if you match something both on colour and shape, and is correct, it is harder to deduce whether you got it right by matching the colour or the shape 3. After 10 consecutive correct answers, the sorting rule changes, unbeknownst to participant, and have to figure it out again 4. A good example of a game with evidence that doesn’t all point in the same direction

Question 39

What components of the WCST correspond with severity of anosognosia scores?

Answer 39

1. No. of categories achieved A category is achieved if you get 10 consecutive card placements correct, eg., sorting by colour * If you achieve 6 categories, the test stops - maximum scores at 6 2. No of perseverative errors (inevitable) A card placement that is incorrect by the current sorting rule but would have been correet by the previous rule

Question 39

What skills do WSCT test related to skills struggled by with anosognosic's?

Answer 39

1. set-shifting 2. complex working memory 3. error detection 4. feedback utilisation

Question 40

How do people with and without anosognosia score on the WSCT?

Answer 40

1. One patient without anosognosia scored 6 on categories achieved and 19% perseverative errors 2. One patient with severe anosognosia scored 0 on categories and 68% on perseverative errors