Summary lectures Cognitive Neuropsychiatry.
Lecture 1. Eating disorders.
People have different perception of the world around them.
For instance through colour constancy.
Our brain is in charge and fools us continuously
Anorexia nervosa.
What is AN?
- Several criteria: reduced energy intake which leads to significant weight loss. Very skinny, still
perceive own body is much bigger than it actually is.
- Also lack of insight in own illness and why it is so dangerous.
- Body image disturbance is important criteria = perceiving own body as bigger than it is.
Prevalence.
- 0.6% of young females.
- 35% relapse.
- 50% chronically ill.
- 5-15% mortality rate.
Research.
- How they think about body and how they perceive their body.
- No effective treatment yet.
- Completed treatment still show body image disturbance.
- Why no effective treatment?
o Several discrepancies between practice and how scientist look at anorexia.
o Researcher mainly focused at anorexia patients thinking and seeing that they are fat. But
they feel that they are fat, really get signals of body that they are fat.
o All senses are involved in all processes and how we perceive own body. Humans are
multisensory beings.
o Neuropsychology body image.
o So shift from clinical psychology to neuropsychology and neuroscience.
o A lot of attention how body is represented in brain and how it is influenced.
Summary.
- Body representation = model/ blueprint of body stored in brain. Set of abstract information of
body. Contains all kinds of information. For example:
o Bodily cognitions (emotions, attitudes, semantics).
o Bodily perception (visual, tactile perception).
o Bodily action (planning/ execution of motor action).
- Input from multiple sense contributes to building a blueprint of the body and its size in the brain.
- Homunculus: map of body in brain. Distorted information is rescaled. Homunculus can be
localized in brain, but mental body representation less clear. Parietal areas involved, but not
specific location.
- Body representation is important in daily life, brain is constantly making calculations that are
body related.
- Determining whether you are fat is not aim of body presentation.
,- Determining whether you are fat is not the aim of your body representation. It is to keep you
safe.
- Mental representation of size of our body is crucial in keeping the body safe and unharmed. Very
automatic behaviour. Starts very young.
Body representation:
- Internal model of our body (blueprint).
- Constructed from information from different senses.
- Abstract info (not just an image).
- Crucial in daily life for bodily cognition/ affect; bodily perception and motor action.
Body representation in anorexia.
- Anorexia patients mainly struggle with the size of their body.
disturbed concept body size. Not entire body representation is disturbed, but parts important
for size of body.
- Likely to affect multiple senses/ modalities.
Can affect cognition and affect, visual perception. Also tactile perception? Or motor planning
and execution?
Tactile size perception.
- Estimating the size between two tactile stimuli.
AN estimate size as being bigger than HC. So AN overestimates the size compared to HC and
actual size.
- Information that you feel on your skin needs to be projected, so from skin to brain. Receptors
can convey a lot of information, duration, sharp, temperature. But cannot convey the relative
distance between two tactile stimuli. Locations of two stimuli need to be projected on
representation of size of body body representation.
So if body representation incorrect projecting stimuli will result in incorrect size estimate.
Anorexia patients feel bigger with their body.
Body scaled action.
- Busy room/ place: super crowded and busy, you automatically map through this. Easy to do this
without thinking, because brain knows how big your body is.
- In lab: door openings. Sometimes you had to move your shoulders to move through these door
openings.
- HC generally really good at this.
When do they get signal from brain that they should rotate shoulders? Body representation is
involved in this.
- HC’s: for smaller openings they made rotating movements and for larger openings no rotating
movements. 25% wider than own body rotating.
- Anorexia: for wider openings, still rotation of body. Safety margin of 40%.
So anorexia patients move their body as if it is bigger.
- So now we now that tactile perception and motor planning & execution is disturbed.
- Body representation disturbance in anorexia is more severe than previously assumed: anorexia
patients do not only think and see themselves as fat, they literally feel fatter and move around as
if their body is bigger.
, Treatment of body representation disturbances in anorexia.
Rubber hand illusion.
- Stroking actual hand and fake rubber hand. Stroke at same time feeling as if rubber hand is
theirs.
Control: stroking is asynchronous do not feel as if hand is theirs.
- Can RHI influence how people perceive own body?
- Before experiment: anorexia overestimate size of own hand.
After RHI: in both conditions reduction in overestimation of width of hand. So they estimate
their own hand as more realistic.
RHI makes anorexia patients more accurate in body size estimations.
Whole body illusion.
- Virtual reality set up for whole body illusion.
Watch their new body in VR, body of avatar touched with brush. Participants would see every
movement with sensor and mimicked with hand.
Also a synchronous condition.
- Had to estimate the width of shoulders, waist and hips.
Before experiment: overestimated this.
After experiment: reduction in overestimation. Patients estimate their body size as smaller.
- So body size perception in anorexia is flexible. Even for emotional body parts. Improved body size
estimation remains over time.
- However, also in the control condition, results are not very uniform, how do patients feel
emotionally?
- This is not a therapeutic intervention.
Hoop training.
- Based on experiment with door ways.
- Hoops of different sizes.
- Patients are instructed to find hoop that they fit into. They have to move through the hoop. Each
session different hoops.
If you tell someone that there are different sizes of colour, your brain will not change. Same for
anorexia, telling is not effective. Mainly changing maladaptive cognition or other perceptually
inspired interventions.
For instance drawing of body outline. Really easy for eating disorder to interfere in this. Why
actual outlining is correct.
- Hope that using hoops can make sure that eating disorders do not interfere.
- Treatment in which patients directly experience (feel) their actual size. Not only visually.
- Based on what we see in pregnant women. Body representation cannot keep up and they bump
into tables, which gives direct feedback signal.
For anorexia, they never bump into things, already rotate body. Don’t accidentally bump into,
thus no feedback signals. That is what they might be lacking and disturbs improvements.
- See hoops, thoughts about hoops, move through a hoop, feel the hoop. Speaks to different
senses of body image disturbance. Directly experienced that they are able to move through small
hoop.
- Often able to choose smaller hoop through sessions. Patients make their choice themselves.
Eating disorder has no one to blame here, hoop has fixed size, therapist cannot be to blame.
