Cognitive Neuropsychiatry | Full Lecture Notes | Utrecht University | A+ Study Notes

LECTURE 1: Body Image Disturbances in Anorexia Nervosa
anorexia: perception is very real (how brain constructs reality)  brain can create illusions and distort reality
Diagnosis of an ED (AN as per DSM-5)
(A) limited food intake dangerously underweight
(B) intense fear gaining weight
(C) disturbed perception/experience of body weight & shape (for self, not others)
Restricting type (diet/fast/exercise)Binging/Purging typePartial Remission: (B/C)Full Remission
Severity: mild BMI > 17, moderate – 16-17, Severe < 15
Perceptual mistake or response bias?  (cognitions, expectations, thoughts)  difficult to tease apart
- Ethical use of force feeding  < 18 = parent decide  > 18 = own decision (judge)
Epidemiology: 0.6% young females 35% relapse 50% chronically ill 5-15% mortality (one of the highest)
- Focus is not eating behaviour but on body perception (see/think about own body)  50 years research with no strong
intervention / treatment
- Current treatment: thinking/seeing (I am fat) = CBT  no consideration of tactile experience (I feel fat)  perception
(discrepancy between knowing and feeling)
- NP - humans are multi-sensory  use senses to understand the world and self (cannot only focus on seeing/thinking)
Models of Body Perception
- NP creates models of body perception in anorexia
Body representation = abstract collection of all body perceptionsintegrates related information  uses input from multiple
senses to create blueprint of body and size in brain (using auditory, visual, tactile info)
- (1) body cognitions = emotions, attitudes, semantics
- (2) body perception (visual, tactile perception)
- (3) body action (planning/execution of motor action)
Homunculus = somatosensory & motor representation in brain
- not representative of how our body feels (e.g. large hands)
- homunculus is rescaled using body representation (not one area of brain, parietal region)
- integrated information across brain and senses
- body awareness = sense of body in space, calculate where body is located in relation to environment, coordinated
movements, judge size & location
- some of body representation is conscious but other calculations & judgments are not
- Main function of the body representation: ensures we can use and move body in the world and protect it from harm
(dodge objects, navigate space, judge distance) false alarm is better than a miss
- Body representation = is not an image includes abstract concepts (joints, kinetics, semantic)
Body Representations in Anorexia: Mainly struggle with body size  no problem with semantic info
- Hypothesis: Disturbed concept of body size stored in body representation  affect multiple senses and modalities
(cognition & affect, visual, tactile perception, motor/planning/execution)
Tactile Size Perception: Touch arm/stomach (emotionally salient) w caliper distance between 2 points
- Arm & stomach normally underestimated in HC (less receptor density in different locations)
- Arm & stomach significantly overestimated in AN (difference in receptor density & sensitivity) more sensitive but less
specific (feel very light touch but cannot tell distance) affected tactile processing
- Receptors in skin relay info to brain (distance/smoothness/duration of touch)  size model of object is projected onto
size representation of body – need a comparison (e.g. if body size representation is larger in AN, then there is a
distorted notion of the object size too) AN feel bigger than they are
Body scaled action: how AN move their body  Moving in crowded spaces (judgement of body size)
- Walk through door frame (rotational movement)
- HC rotate when opening is 25% wider than shoulders (safety margin)
- AN rotate at 40% (brain uses inaccurate size info from body representation to make movements)
- AN also rotate at 25% when the estimated shoulder width is used  stored representation is larger and they use this
to navigate the world  move as if their body is bigger
Body representation disturbance in AN is more severe than assumed  affect multiple senses & modalities  not only think
and see themselves but also experience
Treating Body representation disturbance in Anorexia
- Can we change body size experience use perceptual distortions to improve/treat anorexia (e.g. RHI)
- Synchronous vs asynchronous  synchronous = body ownership
- Estimate hand width pre/post RHI  before = bigger  after = smaller hand (corrected) perception of body size is
modified by RHI  occurs in all conditions (regardless ownership) unclear
- Body Representation illusion of entire body (VR)  overestimate body in pre-condition  still over-estimate body in
post-condition but much lower  3 hours later body improvement remained
- Altered perception in body size is flexible and remains over time  even for emotional body parts even
asynchronous condition  not related to body ownership not therapeutic intervention
Intervention for Anorexia
- Hoop training = choose hoop that exactly fits body  Coach patient through size choose smaller size over time
Cannot come up excuses to fit evidence by direct proof