Disorders of Perception
| Concept/Question | Quick Summary | Exam Hook |
|---|---|---|
| Illusion vs. Hallucination | Illusion: Misperception of a REAL external stimulus (e.g., seeing a face in a shadow). Hallucination: Perception with NO external stimulus. | Illusion = Real stimulus, wrong perception. Hallucination = No stimulus, new perception. |
| Pseudohallucination vs. True Hallucination | True: Perceived in EXTERNAL space (real). Pseudo: Perceived in INNER, subjective space ("in my head"); patient knows it's not real. | True = "In the room." Pseudo = "In my mind's eye." |
| Elementary vs. Formed Hallucinations | Elementary: Simple, unformed perceptions (flashes of light, buzzing). Formed: Complex, clear perceptions (voices, people, music). | Elementary = Simple shapes/sounds. Formed = Complex scenes/speech. |
| Hypnagogic vs. Hypnopompic Hallucinations | Hypnagogic: Occur when going to sleep. Hypnopompic: Occur when waking up ('pomping' out of sleep). Both can be normal. | HypnaGOgic = GOing to sleep. |
| Functional vs. Reflex Hallucination | Functional: Stimulus and hallucination are in the SAME sensory modality (e.g., sound of a tap causes voices). Reflex: Stimulus and hallucination are in DIFFERENT modalities (e.g., sound of a tap causes a visual hallucination). | Functional = Same sense. Reflex = Different senses. |
| Somatic & Related Hallucinations | Haptic: Touch (e.g., being sexually assaulted). Kinaesthetic: Bodily movement (e.g., arm feels like it's moving). Visceral (Coenaesthesia): Inner organs (e.g., brain is burning). | Haptic = Touch. Kinaesthetic = Movement. |
| Specific Visual Hallucinations | Lilliputian: Seeing miniature people/animals (classic in Delirium Tremens). Autoscopic (Doppelgänger): Seeing one's own body/double. Teichopsia: Zig-zag lines (classic in migraine aura). | Lilliputian = Little people. Autoscopic = Seeing yourself. |
| Charles Bonnet Syndrome | Triad: 1. Visual impairment, 2. Complex visual hallucinations, 3. Intact insight (knows they aren't real). | CBS = Bad eyes + Vivid visions + Clear mind. |
| Synaesthesia | Stimulation of one sense leads to an experience in another (e.g., smelling music, seeing colors with numbers). A perceptual anomaly, not pathology. | Synaesthesia = Sensory Crossover. |
| Perceptual Distortions (Metamorphopsia) | Dysmegalopsia: Size/shape distortion. Paraprosopia: Distortion of faces. Paraschemazia: Distortion of one's own body image/shape (e.g., leg feels twisted). Palinopsia: Visual image persists after stimulus is gone. | Palinopsia = Persistent image. Paraprosopia = Perverted faces. |
| Illusions (Types) | Pareidolia: Seeing meaningful patterns in vague stimuli (e.g., faces in clouds). Completion: Mind "fills in the gaps" due to inattention. Affect: Mood influences perception (e.g., fear makes a coat look like a person). | Pareidolia = Patterns in randomness. |
Specific Syndromes & Disorders
| Concept/Question | Quick Summary | Exam Hook |
|---|---|---|
| Levels of Consciousness | Stupor: Unresponsive but appears awake; arousal only with VIGOROUS/REPEATED stimuli. Coma: Cannot be aroused at all. Lethargy: Drowsy but easily aroused. | Stupor = STimulation needed. Coma = Can't wake. |
| Alcohol Withdrawal vs. Deficiency | Delirium Tremens (DTs): Withdrawal (days 2-4). Delirium + agitation + hallucinations. Wernicke-Korsakoff: Thiamine (B1) Deficiency. Wernicke's (acute) = Ataxia, Ophthalmoplegia, Confusion. Korsakoff's (chronic) = Amnesia + Confabulation. | DTs = Detox Delirium. W-K = B1 Brain Damage. |
| Kleine-Levin Syndrome | Classic triad in adolescent males: Recurrent episodes of 1. Hypersomnia (excessive sleep), 2. Hyperphagia (excessive eating), 3. Behavioral disturbances. Return to normal between episodes. | Kleine-Levin = Sleep, Eat, Behave weird. |
| Narcolepsy | Classic Tetrad: 1. Excessive daytime sleepiness, 2. Cataplexy, 3. Hypnagogic hallucinations, 4. Sleep paralysis. | Narcolepsy = Sleep attacks + Collapse with emotion. |
| Dissociative (Non-Epileptic) Seizures | Often long duration (>2 mins), gradual onset, triggered by emotion, no post-ictal confusion. | Dissociative = Long, emotional, no confusion after. |
| Dissociative Fugue | Amnesia (often for identity) + purposeful travel ("flight"). | Fugue = Amnesia + Flight. |
| Ganser's Syndrome | Key feature is giving approximate answers (Vorbeigehen), e.g., "a horse has 5 legs." Also clouding of consciousness and pseudohallucinations. | Ganser's = Giving "near miss" answers. |
| Pseudodementia vs. Dementia | Pseudodementia (Depression): RAPID onset, patient is distressed by memory loss, highlights failures. Dementia: INSIDIOUS onset, patient often unaware/conceals deficits (anosognosia). | Pseudo = "Doc, I'm so forgetful!" Dementia = "Doc, my memory is fine!" |
| Malingering vs. Factitious Disorder | Malingering: Faking for EXTERNAL gain (Money, evade jail). Factitious Disorder: Faking for INTERNAL gain (to assume the sick role). | Malingering = Money. Factitious = Faking to be the patient. |
| Grief vs. Major Depression | Grief: Guilt is specific to the loss. Transient hallucinations of the deceased can be normal. Mood comes in waves. Depression: Guilt is PERVASIVE and generalized. Anhedonia and psychomotor retardation are profound and persistent. | Grief guilt = About the loss. Depression guilt = About everything. Retardation = Depression. |
| Schizoid vs. Avoidant PD | Schizoid: Doesn't want friends. A happy loner. Avoidant: Wants friends but is too afraid of rejection to try. | Schizoid = Doesn't want friends. Avoidant = Wants friends but is scared. |