Psychiatry

1. DISORDERS OF PERCEPTION
Presented by : Dr.A.Padmaja
Moderator: Dr.D.Raj Kiran
Asst. Professor,
KIMS,Amalapuram.

2.  Sensation :
First stage in receiving information from
outside the self.
Receiving sensory information from various
pathways.
 Perception :
It is the organization, identification &
interpretation of sensory information in order
to represent & understand the environment.

3. 1) Sensory Distortions – Constant real
perceptual object, which is perceived in
distorted way.
2) Sensory Deceptions – New perception
occurs may or may not be in response to
external stimuli.

4. Sensory Distortions
 Changes in intensity
 Changes in quality
 Changes in spatial form
 Distortions of the experience of time
 Splitting of perception

5. Changes in intensity:
 Hypo/Hyperaesthesia
intensity of sensations may result of intense
emotions/lowering of physiological threshold.
seen in anxiety, depressive d/o, migraine.
 Hyperacusis
 Hypoacusis
Threshold of all sensations are raised.

6. Changes in quality
 Visual perceptions affected.
 Predominance of colours is seen.
 Palinopsia - recurrence of visual phenomenas
beyond the limit of appearance of real event
in the world.

7. Changes in spatial form
 Change in perceived shape of an object
- micropsia
- Macropsia
- Dysmegalopsia
- Porropsia

8. - Metamorphosia
- Paraprosopia
- Alloaesthesia
- Akinetopsia

9. Distortions of the experience
of time
 Mania- time passes quickly.
 Depression- time passes slowly.
 Temporal lobe lesions- d/o personal time.
 Schizophrenia- abnormalities of time
judgement.

10. Splitting of perception
 Unable to form the usual, assumed links b/w
2 or more perceptions.
 A person watchingT.V experienced a feeling
of competition b/w visual & auditory
perception. She felt that the two were not
coming from the same source but were
competing for her attention & conveying
opposite messages.

11. Sensory Deceptions
Illusions – stimuli from a perceived object are
combined with mental image to produce false
perception.
ex: Muller Lyer illusion
 Occur in delirium when perceptual threshold
is raised, anxious & bewildered patient.
 Visual illusions are common.
 Fantastic illusion- when patient see extra
ordinary modification to their environment.

12.  Completion illusion: depend on inattention
such as misreading words in news paper.
ex- _ook misread as book if faded letter is look
 Affect illusion: arise in the context of
particular mood state.
ex- Bereaved person- see deceased person.
 Pareidolia: vivid illusion occur with out the
patient making any effort.
ex- sees vivid pictures in fire or in clouds.

13.  Trailing phenomena – perceptual
abnormalities in which moving objects are
seen as a series of discrete & discontinous
images.
associated with hallucinogenic drugs.

14. Hallucinations-A false perception which is
not a sensory distortions or a misinterpretation,
but which occurs at the same time as a real
perception.
 Substantial, objective space, clearly
delineated constant & independent of the will
& their sensory elements are full & fresh.

15.  Mental images- incomplete not clearly
delineated, dependent on will, appear in
subjective space, in constant & have to be
recreated.
 Pseudo Hallucination- type of mental image,
although clear & vivid, lack substantiality of
perception.
seen in full consciousness, known to be not
real perception.
insight present.

16. Causes:
 Emotion- depressed pt with delusion guilt
may hear voices.
 Suggestion- normal subjects can be
persuade to hallucinate.
 D/o peripheral sense organ- Charles
Bonnet Syndrome condition in whichVH`s
occur in association with impaired vision
without any psychopathology.

17.  Sensory deprivation- If all incoming stimuli
are decreased to minimum in a normal
subject they began to hallucinate after a few
hrs.
 D/o CNS – lesions of diencephalon & the
cortex .

18. Auditory
 Called as phonemes.
 It may be elementary & unformed &
experience as simple noises, bells or voices.
 Imperative, abusive, neutral or helpful.
 Gedankenlaut werden
 Echo de la pensee
 Origin-T.V, radio, arm, legs, stomach.

19.  Pt hallucinate speech movements & hear
speech that comes from their own throat.
 AVH`s – activation in Brocas area .

20. Visual
 Elementary- form of flashes of light, form of
patterns, form of visions of people/objects.
 Seen in acute organic state like post
concussional state, epileptic twilight state.
 Delirium tremens
 Scenic hallucinations
 Temporal lobe epilepsy-VH`s + AH`s
 Activity in extra striate visual area (
broadmann area 19)

21. Olfactory
 Also called phantosmia.
 Seen in schizophrenia & organic states.
 Olfactory reference syndrome.
 Temporal lobe disturbances- burning
paint/rubber.
 Padrpio phenomenon- some religious people
smell roses around saints.

22. Gustatory
 Also called phantoguesia.
 Depression pt- loss of taste or states that all
food tastes the same.
 OH`s & GH`s co-occur
 On MRI study OH`s & GH`s shows activation
in the brain region for smell & taste.
 This activation is suppressed by treatment
with Atypical AP`s

23. Tactile
 Feeling of small animals crawling over the body
which is known as formication.
 TH`s + DOP seen in cocaine bug
 Sexual hallucinations occur in both acute &
chronic schizophrenia.
 3 types : 1) Superficial:Thermic, haptic, hygric,
paraesthetic
2) Kinaesthetic : occur in alochol int
- oxication & BDZ
withdrawl
3)Visceral

25. Pain & deep sensation
 Visceral H`s
 Chronic schiz – twisting & tearing pain.
 Delusional zoopathy – delusional belief of
animals crawling in the body.
- seen in organic d/o.

26. The sense of presence
 Presence of some one when nobody is there.
 Due to hunger, lack of sleep, religious
enthusiasm.
 Seen in schiz/hysteria/BPD.
 Functional MRI- activation of frontoparietal
lesion.

27. Hallucinatory syndromes
 Refer to d/o in which there are persistent
hallucinations in any sensory modality in
absence of psychotic feature.
 Alcoholic hallucinosis.
 Organic hallucinosis.

28. Others
 Functional H`s- H`s require the presence of
another real sensation.
 Reflex H`s – synaesthesia is the experience
of a stimulus in one sense modality producing
a sensory experience in another.
 Extra campine H`s- Outside the limit of
sensory field. Seen in schiz/ epilepsy.

29.  Autoscopy/ phantom mirror image-
experience of seeing oneself & knowing that
it is one self.
- m/c acute & sub acute delirious states,
epilepsy
- negative autoscopy :organic d/o
- Internal autoscopy

30.  Hypnagogic & Hypnopompic H`s:
- Occur during drowsiness, discontinuous
appear to be force themselves on the subject.
- VH`s – geometrical designs, abstract shapes,
faces, figures or scenes from nature.
- AH`s – animal noises, music, ones name
called.
- Seen in narcolepsy.

31.  Organic H`s:
- any sensory modality.
- seen in neurological & psychiatric d/o.
- phantom limb
- phantom organs
- lesions of parietal lobe: somatic H`s with
distortions or splitting of body parts.
- lesions of temporal lobe: associated with
multi sensory H`s.

32.  Attitude towards hallucinations-
- Organic: terrified & try to get away from
them.
- Delirious: feel threatened & suspicious.
- Lilliputian: amusement.
- Depression : not terrified.
- Acute schiz : frightening
- Chronic schiz: they used to it.

33. Body image distortions
Hyperschemazia
 Perceived magnification of body parts.
 Occur in organic & psychiatric conditions.
 Organic-brown sequard paralysis, PVD,
MS,Thrombosis of PICA.
 Psychiatry-hypochondriasis,
depersonalization & conversion disorder.

34.  Hyposchemazia/Aschemazia- perception of
body parts are absent or decreased in size.
 Paraschemazia – feeling that part of the body
twisted or seperated from the rest.
 Anosognosia – denial of illness.

35.  Somato parphrenia –bizzare attitude to their
paralyzed limb.
 Hemiasomatognosia- u/l lack of body image
in which person behaves as if one side of
body is missing.
 Hemi spatial neglect- neglect of hemispace
on C/L lesion while performing task.

36. References
 Fish`s clinical psychopathology.
 SIMS descriptive psychopathology.