DISORDERS OF PERCEPTION

Dr Sa lman Kareem1 s t y r Post Graduate

Dept of psych iatry

Perception

Individuals capable of receiving information on sensation. Data is then organized to make it meaningful and comprehensible. The organized entities are called percepts. This processing of the data to represent reality is called PERCEPTION.

types

Sensory Distortion- Constant real perceptual object which is perceived in a distorted way

Sensory Deception- new perception that may occur that may or may not be in response to external stimuli

Disorders in the experience of time

SENSORY DISTORTIONS

Changes in Intensity - Increased intensity of sensation- hyperesthesia seen in increasing sensations or lowering of physiological threshold.

Seen in anxietydepressive disorder, Hangover from alcoholMigrainehypochondria cal personalities

Increased sensitivity to noise – Hyperacusis

Decreased sensitivity to noise – Hypoacusis

DeliriousDepressionAttention deficit disorder

CHANGES IN QUALITY

Visual perception – affected by this are brought about by toxic drugs

Xanthopsia- Coloring of YellowChloropsia - Coloring of greenErythropsia- Coloring of red

Derealization- Everything looks unreal and strange

Mania- looks perfect and beautiful

CHANGES IN SPATIAL FORM Change in percieved shape of an object Retinal disease Disorders of accommodation Temporal and Parietal Lobe Lesions Poisoning with Atropine and Hyoscine SCHIZOPHRENIA

Micropsia – a visual disorder in which the patient sees objects

o Smaller than they really areo Farther away than they really are

Macropsia – opposite to micropsia

Experience of retreat of subjects into the distance without any change in space - porropsia

Edema of the retinaPartial Paralysis of accomdationDiseases affecting the nerves

controlling accommodation

MACROPSIA : Scarring of retina with retraction

and complete paralysis of accommodation. DYSMEGALOPSIA: Objects are perceived

larger in one side and smaller in the other.

Atropine, Hyoscine poisoningChronic arachnoiditis METAMORPHOSIA: Irregular in shape.

DISTORTIONS IN THE EXPERIENCE OF TIME

Psychopathological point of view Physical- Determined by physical events Personal- Personal judgement of

passage of timeMania- Time passes quicklyDepression- Time passes slowlyAcute Schizophrenia- personal time goes in

fits and startsAcute organic states (temporal disorientation)

disorders of time is seen in milder form there may be over estimation of time.

SENSORY DECEPTION

Illusions- Misinterpretation of a single stimuli arising from a single stimuli

Stimuli from a perceived object are combined with a mental image to produce a false perception.

Derived from set and lack of perceptual clarity

DeliriumSevere depression with delusions of

guilt

Types of illusion

Complete Illusion – These depends on misreading words in newspapers or missing misprints because we read the word as if it were capable

Affect Illusion- These arise in the context of particular mood state

Paradolia – vivid illusions occur without the patient making any effort ; are the result of excessive fantasy thinking and a vivid visual imagery.

HALLUCINATIONS

False perception which is not a sensory distortion or misinterpretation but which occurs at the same time as real perception.

Essential criteria for an operational definition1. Percept like experience in the absence of

an external stimuli2. Percept like stimuli which has full force and

impact of real perception3. Percept like experience which is unwilled,

occurs spontaneously and cannot be readily controlled by percipient.

causes

Intense emotions Suggestion Disorders of sense organs Sensory deprivation Disorders of CNS Psychiatric disorders

(i)Emotions

depressed patients with delusions of guilt; hallucination tends to be disjointed or short phases

Occurrence of continuous persistent hallucinatory voices in severe depression should arouse the suspicion of schizophrenia or some intercurrent physical disease.

(ii)Suggestions

Normal subjects can be made to hallucinate

Hypnotic hallucinations do not produce objective effects similar to those produced by ordinary perceptions such as complimentary after images and so on

(iii)Disorders of sense organs

Hallucinatory voices may be heard in ear disease

Visual hallucination is seen in eye diseases but usually there is disorder of the CNS as well.

Peripheral lesions of sense organs may play a part in hallucinations in organic states

(iv)Sensory Deprivation

If all incoming stimuli are related to minimum in a normal subject they will begin to hallucinate after few hours

Usually these are changing visual hallucinations and repetitive phrases

BLACK PATCH DISEASE delirium following cataract extraction in the aged result of sensory deprivation and mild senile brain changes

(v)Disorders of CNS

Lesions of diencephalons and cortex can produce hallucination that are not only visual but can be auditory.

HALLUCINATIONS OF INDIVIDUAL SENSES

Hearing Vision Smell Taste Touch Pain and deep sensation Vestibular sensations The sense of presence

Hearing

Hearing (auditors) may be elementary or unformed.

Elementary – noises, bells or undifferentiated whispers ; in organic states

Partly organized- music Completely organized- hallucinatory voices-

schizophrenia- persecutory in nature Severe depression also ‘voices’ can be

heard but less well formed than schizophrenia

Imperative hallucination Voices sometimes act upon individuals

and give instructions. may or may not act upon themAuditory hallucinationsAdverseNeutralHelpful Incomprehensible nonsense Neologism

Thought echo - hearing one’s own thoughts being spoken loud, voice may come from inside or outside the head.

i. GEDANKENAUTWERDEN- thoughts are spoken at the same time or before they are occurring.

ii. ECHO DE LA PENSES- thoughts are spoken just after they occurred.

Running commentary hallucinations are usually abusive.

VISION

Elementary- flashes of light Partly organized- patterns Completely organized- visions of

people animals or objects.Scenic hallucinations- whole scenes

are hallucinated like a cinema filmMore commonly seen in delirium seen in psychiatric disorders

associated with epilepsy.

Patients with visual and auditory hallucinations co occur as a whole

Temporal lobe epilepsyLate onset of schizophrenia

(protracted)

Visual Hallucinations are more common in organic states with clouding of consciousness than in the functional psychoses

Small animals are often hallucinated in delirium

Extremely rare in schizophrenia Occasionally without any psychopathology

CHARLES BONNET SYNDROME Produced by drugs of abuse typically consist

of diffuse distortions of existing visual world.

smell

Seen in Schizophrenia Organic states like temporal lobe

epilepsy Depression (uncommon)PADRE PIO PHENOMENON- religious

people can smell around certain saints

Taste

Seen in Schizophrenia Organic states

Depressed patient often describes loss of taste.

Touch

Formication- a feeling that animals are crawling over the body; not uncommon in organic states

Cocaine bug – formication occurring with delusion of persecution in cocaine psychosis

Sexual Hallucinations- seen in acute and chronic schizophrenia

Classified into 3 types1. Superficial2. Kinesthetic3. Visceral

Superficial

Thermic – a cold wind blowing across the face

Haptic- feeling a hand brushing against the skin

Hygic- feeling fluid such as water running from the head into the stomach

Paraesthetic- pins and needles. Mostly organic.

Kinesthetic Hallucination

affects muscles and joints Patient feels their limbs are being

twisted pulled or moved Seen in schizophrenics Organic states such as alcohol

intoxication and benzodiazepine withdrawal

Pain and deep sensation

Visceral hallucinations (SIMS 2003). Twisting and tearing pains Very bizarre complaints- organs

being ripped out and flesh ripped from his body

Seen in chronic schizophrenia

The sense of presence

Organic statesSchizophreniaHysteriaNormal people – feverently religious

PSEUDOHALLUCINATION

Type of mental image that although clear and vivid lack the substantiality of perceptions

Full consciousness Located in subjective space Definite outlines, compete sound Constancy retained Relevant to emotions, needs and actions Depends on the observer for existence

HystericalAttention seeking personalities

SPECIAL KINDS OF HALLUCINATIONS

Functional hallucinations : a auditory stimulus causes the hallucination, but it is experienced as well as the hallucination.

Chronic schizophreniaReflex Hallucination : a stimulus in

one sensory field produces a hallucination in one another. Morbid variety of synaesthesia.

Extracampine hallucination : Hallucinations that is outside the limits of the sensory field.

o Seen in healthy people as hypnagogic hallucination

o Schizophreniao Organic conditions- epilepsy

Autoscopy (phantom mirror image) -The patient sees himself and knows that it is he. Not just visual hallucination , because even kinesthetic and somatic sensations are present

Normal subjects- emotionally disturbed, tired and exhausted

depressed Hysteria Schizophrenia

Acute and sub acute delirious states Epilepsy Focal lesions in parieto occipital region Toxic infective states whose effect is

greatest in basal regions of the brain Drug addiction Chronic alcoholismNEGATIVE AUTOSCOPYINTERNAL AUTOSCOPY

Hypnagogic Hallucination Occur when the subject is falling asleep

during drowsiness Are discontinuous Appears to force themselves on the subject Do not form part of an experience in which

the subject participates unlike DREAM Commonest is auditory. His name being called May be geometrical designs , abstract shapes

, faces , figures or scenes from nature EEG shows alpha rhythm

Hypnopompic Hallucination

Occurs when the subject is waking up

Hallucinations persisting from sleep when the eyes are open

More in narcolepsy.

Organic Hallucinations

Occurs in any sensory modality and may occur in various neurological or psychiatric disorders

Depends oni. General condition of the brainii. Recent experiencesiii. Psychodynamic factorsiv. Effect of local lesion

(i)Visual hallucinations

Stimulation of visual projection areas in the walls of the calacrine fissure causes perception of flashes of light as does stimulation or irritation of optic radiation.

Lesions of optic tract and lateral geniculate bodies.

Spontaneous V H – sensory defect Complex scene hallucination – stimulation

of posterior part of temporal lobe.

(ii)Tactile hallucinations

Almost exclusively the result of lesion which produces sensory defect

PHANTOM LIMB Most common organic somatic

hallucination 95% of amputation after 6 yrs of age Pt feels he sees the limb from which in

fact he is not receiving any sensations either because limb has been amputated or sensory pathway destroyed.

Most phantom limbs are produced by peripheral and central disorders.

Occasionally it develops from lesion of peripheral nerve or the medulla or spinal cord.

Thalamoparietal lesions have phantom third arm or leg.

Correspond to the previous image of the limb.

(iv) Auditory hallucinations

Whistling , buzzing, drumming and even bells heard by patients with middle ear disease or internal disease

Caused by epileptic foci and space occupying lesions in the temporal lobes

HALLUCINATION OF TASTE

Occurs most often in temporal lobe epilepsy ass with salivation and chewing and sniffing

Stimulating the depths of the sylvian fissure around the transverse temporal gyri.

OLFACTORY HALLUCINATIONS temporal lobe epilepsy.

TEMPORAL LOBE HALUCINATIONS

These are multisensory hallucinations but they do not include somatic sensations, which is to be expected because the somatic sensory area is separated from the temporal lobe by sylvian fissure.

HALLUCINATORY SYNDROMES

1) Confusional hallucinosis: i. consciousness is cloudedii. Visual hallucinosis are prominentiii. Auditory hall are mainly music , noises or

odd words but connected sentences are already heard.

2) Self reference hallucinosis:i. Pt hears people talking about himii. Rough idea about what the voices are

saying but unable to reproduce them

3) Verbal Hallucinosis Pt hears clear voices which talk about him

and he can reproduce their content accurately

4) Fantastic hallucinosisi. Hallucinosis of all kinds seem to occurii. Pt describes fantastic experiences based on

auditory and visual hallucinationiii. Sometimes the patient describes dream

experiences as if they were realiv. These pts usually have mass hallucinations

BODY IMAGE DISTORTIONS Hyperschemazia –

percieved magnifications of body parts

When part of the body feels larger than the normal

ORGANIC CAUSESo Brown Sequard

Syndromeo PVD, MS,

thrombosis of PICA NON ORGANIC

CAUSESo Hypochondriasiso Conversion

disordero Depersonalization

Aschemazia- perception of body parts as absent

Hyposchemazia – Body parts as diminished

Paraschemazia – distorted of body image as a feeling that body parts are distorted or twisted from rest of the body.

Hemisomatognosia- Unilateral lack of body image in which the person behaves as if one side of body is missing

Anosgnosia- ‘denial of illness’ –Rt hemisphere strokes denied their knowledge early after stroke and refused to admit to any weakness in their left arm

Somatoparaphrenia- delusional beliefs about the body, distorted, inanimate , severed, or in any other ways abnormal.

THE END

Fish PsychopharmacologyAndrew Sims- Symptoms in the mindComprehensive text book of Psychiatry- Kaplan and Saddock