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 typePartial 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 perceptionsintegrates 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
, - AN actually experience their body size (thinking/ talking/seeing/moving/feel) = multisensory visual size estimation +
tactile size estimation + action planning supplement treatment
Current interventions focus on talking (see 5 shades not seven – cannot be forced) AN cannot see their body the way other
people see it multimodal disorder of distorted body representation
ARTICLE 01: Body Representation Disturbances in Visual Perception and Affordance Perception persist in eating disorder
patients after completing treatment
ABSTRACT: body image disturbance (BID) key of EDs studies limited to cognition + affect (interviews/questionnaires)
examine full scope of mental body representation (e.g. body attitudes, visual perception of body size, tactile perception,
affordance perception) ED and Completed Eating Disorder Treatment (CEDT) groups = larger overestimations in Visual Size
Estimation (VSE) and Hoop Task (HT) no difference between ED, CEDT, and HC in Tactile Estimation Task (TET) existing
disturbance in visual perception and affordance perception in CEDT need multiple sensory modality treatment
- ED = severe impair psychosocial function & physical health AN, bulimia, Feeding/eating disorder
- Incorrect notion of own body size = Body Image Disturbance (BID) contributes to development and maintenance of
EDs & complicates recovery
- Understand body image of CEDT = insight into which aspects of BID are still affected after recovery
- Cognitive neuroscience = brain processes multimodal info of body from different sensory modalities + integrates into
coherent abstract higher-order representation mental body representation stores info (e.g body size, visual, tactile,
cognitions, affect)
- ED = disturbed body attitudes (thinking/imagining), Visual (seeing), haptic, tactile (feeling), affordance
perception/bodily action (knowing what one can do with body size) = enlarged mental representation
- CBT address weight/shape thoughts body image interventions = mirror exposure no standardized model for BID in
ED (heterogeneity of BID treatment approaches)
- Recovery determined by BMI/self-reports/questionnaires tactile perception & affordance perception /bodily action
not measured BID persists after recovery (disturbed bodily experience) trait factor? Trait factor = stable
pattern of thoughts/emotions over long period
- BID = complex aspect of ED does not simply diminish following weight gain
This study: explore mental body representations in CEDT with HC & AN assess 4 domains where BID in AN are found: body
attitudes + visual size perception + tactile perception + affordance perception stronger neg. attitudes in AN to CETD or HC
- multisensory BID symptoms: Visual Size Estimation task (VSE), Tactile Estimation Task (TET) & Hoop Task (HT)
persisting BID in AN, expect larger size estimations on VSE, TET and HT for AN & CEDT
Results: BAT = measure bodily attitudes: AN = stronger negative attitudes toward own body compared to CEDT/HC, CEDT and HC
did not differ on body attitudes beside lack familiarity with body.
- VSE = estimate body size difference across groups: AN > misestimation, then CEDT, then HC
- TET = no difference in tactile estimation on stomach for AN & CEDT & HC
- HT = AN & CEDT overestimated hoop diameter compared to HC AN > overestimation than CEDT
Discussion: investigated multiple aspects of BID in AN persist after treatment treatment focuses on thoughts & emotions
and less on sensory perception
- Assess BID in 4 domains: (1) body attitudes (2) visual perception (3) tactile perception (4) affordance perception
confirm expectation of BID in CEDT in visual perception and affordance perception but not in bodily attitudes AN hold
stronger bodily attitudes compared to CEDT & controls
- AN and CEDT have larger overestimation of body size in visual perception and affordance perception
- No difference in tactile perception between AN, CEDT, and controls
- Need to consider more effective body image interventions self-reports = limiting
- No explanation for absence of significant effects for group differences on TET
- BID symptoms are not fully targeted in treatment since BID symptoms still exist in CEDT too little time spent on
visual perception and affordance perception
- RHI can change internal body representation using sensory modalities can be altered engaging multiple sensory
domains in BID treatment can improve efficiency of conventional treatments
- BID symptoms persist in CEDT urgent predict relapse
ARTICLE 02: A Virtual Reality Full Body Illusion Improves Body Image Disturbance in Anorexia Nervosa
ABSTRACT: AN = persistent distorted experience of body RHI improves hand size estimation in AN explore full-body illusion
(FBI) affects body size in more emotionally salient body parts? experience ownership of VR body after synchronous visuo-
tactile stimulation METHOD: estimate body size (shoulders/abdomen/hips) pre/post/FU (2.75 hrs) AN < overestimation of
body parts after FBI (strongest for circumference) also in asynchronous condition improvements still observed at FU
CONCLUSION: disturbed body size experience in AN is flexible and can be changed, even for highly emotional body parts
- Key symptom AN = disturbed body representation underweight yet experience self as fat central to development,
prognosis, maintenance, relapse difficult to treat, persists after treatment
- Treatment AN = changing cognitions & visual-perception NOT targeting multisensory disturbance
- Body representation = how we experience body & size sub-representations: body image (perceptual body
representation) & body schema (motor action)
- Way we perceive body depends on multi-sensory input Body image in AN also manifest in overestimation of tactile
stimuli, disturbed haptic perception, altered integration of visual & proprioceptive info, abnormal body scaled action,
decreased interoceptive awareness/sensitivity cross-modal integration of sensory signals = disturbed
, - NB to understand role of different sensory modalities in body size experience & interaction between sensory modalities
- Multisensory body illusion = RHI experience ownership over fake body visuo-tactile conflict: seeing touch on fake
body, while feeling touch on actual hand causes brain to integrate the two separate streams (location and size of RHI
are incorporated into the body representation in brain)
- Acute and recovered AN = more susceptible to RHI than HC
- After RHI AN = initial overestimation of hand-width disappeared normalize disturbed body size experience in
experimental setting using multisensory body illusion does not depend on embodying fake body (asynchronous)
based hand size estimates on most recent available visual input underlying mechanism unclear
- Full-body illusion (FBI): ownership of VR female body with healthy BMI estimate body size according to how they
subjectively feel/experience their body
- AN = discrepancy between knowing their size and feeling their size cognitively know they cannot be fat but infer
from their body experience that they have fat on their body
- FBI affects size estimates of the experienced body (How they feel their size), but not estimates of the physical/structural
body (knowledge stored in memory) structural body = more stable & less susceptible to illusions
Methods: estimated width & circumference of shoulders, abdomen, hips pre/post/FU
Experiment: FBI induced twice synchronous & asynchronous abdomen stroked 90s with soft brush
Measures: Embodiment questionnaire (EQ) = subjective experience of illusion
Results: Before FBI(baseline) AN misestimated body width & circumference but not height After FBI: AN & HC decreased
misestimation in synchronous condition AN = decrease in abdomen circumference but not in HC At FU: AN size estimates of
shoulder width and circumference had normalized AN = decrease overestimation of hip circumference changes from pre-
to-follow-up were larger in AN group
- Experimental FBI alters how individuals perceive body size (independent of ownership) positively affects AN
persistent disturbance in body size after and at FU Confirms it is possible to change AN disturbed body size
experience for emotional and non-emotional body parts using FBI
- Changes in body size estimation in synchronous/asynchronous = embodiment does not result in fake body being added
to body representation fake body replaces actual body congruent multisensory cues are not required for FBI to
occur but may strengthen the illusion
- Subjectively reported more embodiment after synchronous but did not show larger changes in size estimation
- AN overestimate body size about 10% more when perceive body in mirror than compared to memory
- HC body size did change and were not stable possibly people use size estimates based on most recent visual info
showed changes in size estimation of shoulders which were not shown in VR
- Future directions: NB different sensory modalities model avatar according to actual body
- Clinical understanding: image disturbances in AN are malleable and improvements last hours AN have weaker
central coherence compared to HC (poor global processing), more detail focused = bias toward specific body parts
visual processing bias = overestimate body size by blocking visual input from own body, participants estimate own
body as smaller (shift from visual info to other senses) feel their body The illusion itself not seem associated with
improved body size estimation but the experimental setting is more NB
LECTURE 2: Dissociative Disorders:
Dissociation = outer-body / unreality / memory lapse categorical differences: Amnesia (how I got there?) Absorption
(intent focus, not taking in environ derealization/depersonalization (world/self not real)
Dissociative Experience Scale (DES-II): 28 items rating scale for dissociation
- frequency & intensity of these experiences dictates disorder threshold
Curious Experience Survey: 31 items severe pathological versus subclinical dissociation
- Compare groups: Adults < students on dissociation Students = Schizophrenia on dissociation Dissociation
decreases with age DES-T measures more severe dissociation (more reflective of samples)
Pathological Dissociation:
- Dissociative Amnesia = cannot recall info about self/events/people, especially during traumatic time
- Dissociative Fugue = sudden unplanned trips from home/work without ability to remember individual’s past (running
away) take on new characteristics not related to original identity after fugue episode resolves, unable to
remember events of the state
Reason for dissociation (heterogenous)
- sleep deprivation/ trauma protection/ coping (mind shuts off) high emotional intensity escape
- Adverse experience = core of dissociation depends on severity & duration of abuse
- critical periods where children are more affected
DSM 5 Dissociative Disorders:
- Dissociative amnesia
- Depersonalization-derealization disorder
- Other specified dissociative disorder (umbrella)
- Unspecified dissociative disorder (umbrella – catchall)
- Dissociative identity disorder (most extreme manifestation of depersonalization)
ICD-11 Dissociative Disorders
- Dissociative neurological symptom disorder
- Dissociative amnesia
