disorders of perception (1).pptx
Transcript of disorders of perception (1).pptx
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DISORDERSOFPERCEPTION
Presenter : Dr. Imon Paul
Chairperson : Dr. Shyam Sunder
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PERCEPTION
Interpretation of what we take in through our
senses
Requires sensation information to be taken in
from outside world
Eliminating the irrelevant
Associating what is seen with other relevant data to
form a percept
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ABNORMALPERCEPTION
Sensory distortions
Changes in intensity
Changes in quality
Changes in spatial formConstant real
perceptual object
percieved in distorted
way
False perceptions/
sensory deceptions
Illusions
Hallucinations Pseudo-hallucinations
New perception which
may/may not be in
response to externalstimulus
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SENSORYDISTORTIONS - INTENSITY
Hyperasthesia
Intense emotions
Lowering of
physiological threshold Neurotics and
hypochondriacal
personalities
Hypoasthesia
anxious preoccupation
delirium (rise in
threshold)
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QUALITY
Mainly visual distortions
Usually due to toxic substances, some
antihelminthics
Xanthopsia- caffeinism Chloropsia - digitalis toxicity
Erythropsia- preretinal and vitreous haemorrhage
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SPATIALFORM/ DYSMEGALOPSIA
Micropsia
Macropsia Metamorphopsia- Retinal diseases- Disorders of accomodation and convergence
- Temporal lobe lesions
- Delirium, degenerative brain diseases affecting visual
association cortex- Atropine/hyoscine poisoning
Porropsia- retreat of objects without change in size
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SENSORY DECEPTIONS
Illusions
Hallucinations
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SENSORY
DECEPTIONS
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ILLUSIONS
Misinterpretation of stimuli arising from an external
object
Stimuli from a perceived object are combined with a
mental image to produce a false perception
transformations of perceptions coming about by a
mixing of the reproduced perceptions of the
subjects fantasy with natural perceptions
(Hagen)
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TYPES
Completion
depend on inattention for occurrence
Incomplete perception meaningless of itself isfilled in by a process of extrapolation from
previous experience to produce significance
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Affect
combination of heightened emotion and
misperception
Can be understood in context of prevailing moodstate
A child waking up in the middle of the night
scared in the dim light , mistakes the towel
hanging on the wall for a person
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Pareidolic
- are created out of sensory percepts by an
admixture with imagination.
- Images seen from shapes- the percept takes on a full and detailed appearance
- becomes more intricate with attention
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Fantastic illusions
Person sees extraordinary modifications of his
environment eg. Looking into a mirror and seeing
head of a pig instead of own head.
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D/D
Intellectual misinterpretation
Functional hallucination
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HALLUCINATIONS
A perception without an object
(Esquirol)
A false perception, that is not a sensory distortion ormisinterpretation but which occurs in the same time
as a real perception
(Jaspers)
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Three criteria are essential for hallucination:
1. Percept like experience in the absence of a
stimulus
2.
Has the full force and impact of a real perception3. Which is unwilled, occurs spontaneously, cannot
be readily controlled by the recipient
(Slade)
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CAUSES
Emotional states
Suggestion
Sensory deprivation
CNS disorders
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CLASSIFICATION
Sensory Modality: Visual, Auditory, Olfactory,
Gustatory, and Kinesthetic.
Form: Elementary and Formed.
Precipitating circumstance: Functional, reflex,
hypnagogic, and hypnopompic.
Degree of attenuation of reality: True
hallucination, pseudo-hallucination and Imagery
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AUDITORYHALLUCINATIONS
May be
elementary noises
partly organized music
completely organized voices Imperative
Seen in schizophrenia, affective psychoses, chronic
alcoholic hallucinosis
content could be commanding, critical, abusive
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Schniderian first rank symptoms:
- hearing ones thoughts being spoken aloud
( Gedankenlautverden)
- voices speaking about patient in third person- voices in form of running commentary
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VISUALHALLUCINATIONS
Types:
Simple - colored lights
Partly organized - geometric shapes
Completely organized - scenes, humans, animals
Seen in organic brain conditions like occipital or
temporal lobe lesions, dementing illnesses, sensory
deprivation, eye pathology, hallucinogens
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Delirium tremens seeing rats, mice, squirrels,
spiders, insects, lilliputian etc
Scenic hallucinations epilepsy, oneiroid states
visions of fire, religious scenes etc
Combined auditory visual hallucinations in
temporal lobe epilepsy
Very uncommon in schizophrenia
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OLFACTORYHALLUCINATIONS
occur in schizophrenia, temporal lobe epilepsy
(commonly aura) and some other organic states.
The smell may or may not be pleasant but usually
has a special and personal significance
For eg- people putting poisonous gas/ anaesthetic
into the house
sometimes relating to oneself I smell repulsive
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A delusion in which a patient believes himself to
smell malodorously without an accompanying
olfactory hallucination is common in schizophrenia.
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GUSTATORYHALLUCINATIONS
Can occur in schizophrenia (odd tastes in food,
food is being poisoned, etc.)
Difficult to establish whether these are clear
hallucinations at times
Can also occur in temporal lobe epilepsy
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HALLUCINATIONSOFBODILYSENSATIONS
May be superficial, kinaestheticorvisceral
superf ic ial :
Thermic
Haptic a dead hand touched me Hygric a perception of fluid
all my blood has dropped into my legs
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Kinaesthetic:
- of muscle or joint sense
- perception of limbs being twisted or muscles being
squeezed.
- in schizophrenia, organic states, withdrawal states
from BZDs or alcohol
Visceral: sensations referred to internal organs,
common in schizophrenia
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Formication/ cocaine bugs
Internal delusional zoopathy :
- eg: sensation of a wasp wandering inside the body
External delusional zoopathy:- sensation of an animal crawling about on the body
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PSEUDO-HALLUCINATIONS
A type of mental image which although clear andvivid,
- lack the substantiality of perceptions,
- are seen in full consciousness,
- located in subjective space.(Jaspers)
Difference between real and pseudo-hallucinationsdepends on the absence or presence of insight.
(Hare)
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True Perception
- Substantial
- Objective Space
- Clearly delineated
- Constant
- Independent of will
- Sensory elements: Full& Fresh
Mental Image /Fantasy
- Incomplete
- Subjective space
- Not clearly delineated
- Inconstant
- Dependent on will
- Have to be recreated
(Jaspers)
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PSEUDO-HALLUCINATIONS
Similarities to True
perception
- Clear & Vivid
- In full consciousness
- Involuntary
Similarities to Mental
Image / Fantasy
- Type of Mental Image
- Lack the substantiality
- Not a real perception
- Subjective Space
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Perception=Hallucinati
on
Pseudohall
ucination
Imagery
Experience Concrete, tangible,
objective, real
Inner eye Pictorial subjective
Location Outer obj. space Inner subjective
Definition Definite, complete Indefinite, incomplete
Vividness Full, fresh, bright Dim, neutral
Constancy retained evanescent
Independence Cannot dismiss/recall at
will
Voluntary creation
Insight Quality of perception Quality of idea
Bhv. relevance relevant Not relevant
Sensory
modality
Another modality Not possible
Existence independent dependent
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SPECIFIC/NAMEDHALLUCINATIONS
Functional hallucinations:
- occurs only in the presence of an external stimulus
in the same modality, but is perceived separately
(eg. hearing voices only when a fan is switched on,
though the sound of the fan is perceivedseparately)
- both perceptions are distinct and real
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Synesthesia:
- is the stimulation of one sensory modality eliciting a
perception in a different sensory modality, as in
seeing a sound.
- associated with toxic states,
- considered the classic perceptual disturbance of
LSD intoxication
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Reflex hallucinations:
- a morbid variety of synaesthesia in which a
stimulus in one modality (eg. Hearing someone
laugh) produces a sensation in another modality
(eg. a pain in the chest)
Extracampine hallucinations: hallucinations
experienced outside the limits of sensory field
Imperative: voices giving commands
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Autoscopy : experience of seeing oneself and
knowing that it is oneself
Negative autoscopy :looking in the mirror and
seeing no image at all.
Internal autoscopy: seeing ones internal organs
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Experiential:hallucinations of past memories
(visual and auditory) in temporal lobe epilepsy
Hypnagogic / hypnopompic: occurring as subject
is falling asleep or waking up; generally a normal
phenomenon
Cenesthetic:bizarre visceral hallucinations in
schizophreniasemen travelling up my vertebral
column to brain where its laid out in sheets"
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Lilliputian hallucinations:visual hallucinations of
small figures / animals (i.e. with micropsia), usually
perceived as pleasant
Charles Bonnet syndrome: visual hallucinations
of human / animal figures in elderly patients with
eye disease, in the absence of other
psychopathology
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Phantom limb: perception of sensation from a limb
that has been amputated (or, more rarely)has been
denervated
- Occurs in about 95 percent of amputees
- does not necessarily correspond to previous image
of the limb
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EVALUATINGHALLUCINATIONS
Schizophrenia: usually distinct and continuousvoices, often in the third person, male or female,delusional elaborations
Depression: rarer (about 10-20% in psychotic
depression), intermittent, disjointed voices Organic states: usually less well formed,
elementary, simple voices (but depends on site oflesion
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Alcoholic hallucinosis: auditory hallucinations,derogatory or threatening
Delirium tremens: visual hallucinations (usuallysmall animals, insects)
Epilepsy: all modalities may occur in temporal lobeepilepsy
Dementia: visual and auditory hallucinations,simple or partly organized
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Hallucinatory syndromes
Confusional
Self reference
Verbal Fantastic
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DESCRIBINGHALLUCINATIONS
Modality : Auditory
Level of consciousness
From Outside or Inside
Known / Unknown peoples voices Content - Pleasant / Unpleasant
Intermittent / continuous / running commentary type
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Directly to the patient or talking among themselves
Commanding / Non-commanding
Controllable or not Insight
Acting out behaviour
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THANKYOU