6.0 Psychopathology of perception

Psychopathology of perception

perception

• Neurocognitive function → ability to integrate sensory information from outside world, & give meaning to it.

• depends on prior experiences 

sensation & perception act together →

• sensory information is analyzed, organized & interpretted, influenced by expectations & experience.

perception helps

• relate to environment

two types of sensory perception

• Sensory distortions

• Sensory deceptions

Sensory distortions

• changes in intensity

• changes in quality

• changes in spatial form 

• changes in associated feelings 

• distortions in perspective integration 

• distortions of the experience of time 

changes in intensity

• increase or decrease in the intensity of stimuli

• anesthesia → complete absence of all for of sensation in an affected area = no sensation

names of pathologies “change in intensity”

• Anesthesia

• Paresthesia

• Hyperesthesia

• Visual hyperesthesia

• Touch sensitivity

• Hyperacusis

• Smell sensitivity

• Taste sensitivity

• Hypoaesthesia

• Hypoacusis

• Achromatopsia

Anesthesia

• complete absence of all forms of sensation in an affected area = no sensation

• complete absent of intensity

paresthesia

• abnormal sensations

• a specific type 

• manifest tingling, numbness, buring or a "pins & needles" sensation

• typically felt in the extremities (hands/feets)

Hypersthesia

• Increased intensity of sensations → heightened sensitivity to sensory stimuli of any of the senses: 

• visual hypersthesia 

• touch 

• hypercausis (auditory)

• smell 

• taste 

Visual hypersthesia 

increased intensity to colour → light, may experience discomfort in bright environment.

Normal conditions of hypersthesia

• may result of intense emotions

• physiological threshold 

Hypomanic / manic conditions 

• epileptic aura/ migraine, or under the influence of LSD/ alcohol

• (overstimulation of NS)

Hypoaestheisa

• decreased intensity → threshold for all sensations is raised 

Hypoaestheisa normal conditions

• depression

• dementia 

• schizophrenia 

Hypocausis

• decreased sensitivity to noises

• seen in delirium or depression & ADHD

senses affected in Hypoacusis

vision, taste, touch, smell, sound

Achromatopsia 

complete absence of color

• appears in nilateral/bilateral occipital lesions

change in quality 

• Change in perception quality of the stimulus of the perception. 

• changes visual perception (due toxic substances) & taste

• alteration in sharpness

• alteration in detail of images

• derealization - appears as strange

• mania - objects look beautiful

coloured visions → changes in quality

• Xanthopsia

• Chloropsia 

• Cyanopsia

• Erythopsia

• Chloropsia

green 

• Xanthopsia

yellow

• Erythopsia

red

• Cyanopsia

blue

quality change in taste

• most common drug is metallic taste associated with the use of lithium

qualitaiative changes occurs mainly with

visual perception

• toxic substances 

coloured vusions

over a object they are looking at

xanthopsia - yellow

chloropsia -  green

cyanopsia - blue 

erythropsia - red

changes in spatial form

• result of a change in the spatial form of the stimulus of the perception 

• changes in perceived volume, shape, & spatial placement

• micropsia 

• macropsia

• Dysmegalopsia

• Metamorphosia

• Porropsia

• Heautometamorphosia

• Hyperschemazia

• Hyposchemazia

• Aschemazia

• Koro

• Paraschemazia or distortion of body image

Micropsia

• size → seeing object as smaller/far away

macropsia

• size → of perception is large/ very close 

Dysmegolopsia

• size → larger / smaller on one side than the other

• only on half of the object, not the complete. 

metamorphosia 

perception of objects irregular in its shape 

Objects around me look distorted

Porropsia

• retreat of objects into the distance without any change in size

• stationary objects appear to be moving away from the observer 

Heautometamorphosia

• result of a change in the spatial form (shape/size/proportion) 

• more complex

• distortion/change/alteration of the body or some of its parts  

• common in hallucinogen poisoning & some neurological conditions

I am the one looking distorted

hyperschemazia

• perceived maginfication/overestimation/ exaggeration

• body size or shape 

hyperschemazia part of disorders 

• Psychiatric conditions → anorexia

• Organic conditions → multiple sclerosis

hyposchemazia

• perceived body parts as diminished 

Aschemazia

• perceived body parts as absent 

• common in sensory deprivation of weightless

• parietal lobe lesion 

koro

a culture-specific syndrome usually seen in chines people

• who belief that the penis is shrinking & will retract into the abdomen & cause death. 

Paraschemazia

• Parts of the body are distorted or twisted or separated from the rest of the body

• (may occur in hallucination, migraine)

body image distortions 

• is not necessarily abnormal perception 

• physical object that has both symbolic & aesthetic value 

• a distorted subjective experience of the body 

• body can be appraised → aesthetical unattractive, in the absence of demonstrable abnormality of the body image.

• occurs in dysmorphophobia

Sensory distortions 

• constant real perceptual object perceived in a distorted way

• sensory organs are central 

• perceiving in a distortion “there are something there, something everyone can see, detect, feel → but the perception is distorted, e.g. in intensity, quality”

changes in associated feelings

• change in experience of stimulus of the perception

• pathological experience of familarity, unreality, pleasure or displeasure of perception

Depersonalisation & derealisation 

• patient reports perceptions changed in quality making them feel unreal/distant 

• alterations in the state of consciousness, memory or affective/emotions.

Derealistation

• reality/world 

• quality of changes in the external world 

• world looks strange, objects might have changed (shape, tone or size)

• unreality or detachment from the world

• sensory changes: environment is distorted (space, time)/blurry

• like a film set, a dream, or a trance (not real)

depersonalisation

• persona

• “I am strange”

• detached from oneself (thoughts, emotions)/ loss of normal identity and physical body.

• oneself is perceived as unreal, strange there is feeling of detached, as if one is an external observer of one´s mental process or body. 

• experience of the own body (separation)

Distortions in perceptive integration

• failure in integrating perception

• unable to form the usual/assumed links between 2 or more perceptions

Types of distortions in perception

• Splitting of perception

• Agglutination

• Synaesthesia

Splitting of perception

• connections between sensory modalities are not established correctly 

• coming from different sources

• stimuli is real, but perceived in not an integrated way

Agglutination 

• The different sensory qualities merge into a single perceptual experience

• unable of distinguishing between different sensations

syneasthesia

• abnormal association of different sensations

• many varieties

• characterized by perceiving a sensory stimuli (e.g. auditory) though another perceptual modality (e.g. visual).

• hallucinogenic

dirstortions of the experience of time

results of a change in the experience of time

• physical time → physical event

• personal time → personal judgement

• regulation of emotional & physiological arousal are also involved in the processing of time.

time´s flexibility - how we perceive the time.

Sensory deceptions

• illusions

• hallucinations