neurology of delusions orrin devinsky neurology of delusions orrin devinsky

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  • Neurology of Delusions Orrin Devinsky Neurology of Delusions Orrin Devinsky
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  • Delusion Pathological, fixed idea Cannot be overturned by evidence Not culturally or religious condoned Can be bizarre or non-bizarre Occur in primary psychiatric disorders (schizophrenia, delusional disorders) and secondary neurological disorders
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  • Delusions in Psychiatry Schizophrenia - often bizarre Influence, persecution/paranoia, self-significance Psychosis due to mood disorder Delusional disorder - prominent non-bizarre delusions lasting > 1 month Erotomania Grandiose Jealous Persecutory Somatic Mixed
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  • Delusions in Neurological Disorders Generalized Neurological Disorders Neurosyphilis (grandiose) Dementia - Alzheimers, Multi-infact, Lewy body disease Parkinsons disease Toxic-metabolic Epilepsy Postictal & interictal Focal Neurological disorders Stroke Tumor Head trauma Epilepsy Interictal & postictal
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  • Content Specific Delusions in Neurological Disorders Delusional misidentification syndromes Reduplicative paramnesia Capgras Fregoli (a stranger is believed to be a familiar person) Othello (delusional jealousy) De Clerambault (erotomania) Cotard (belief one is dying or dead)
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  • Content Specific Delusions: Poles of Familiarity Loss of familiarity People Capgras Mirror sign Places Foreign reduplicative paramnesia (home is considered a duplicate in another location) Disorientation for place (familiar place exists in another location) Hyperfamiliarity People Fregoli (a stranger is believed to be familiar) Places Reduplicative paramnesia (foreign place is considered familiar location)
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  • Content Specific Delusions: Neuropsychiatric Pendulum Before 1975 psychiatric Early 1990s increased awareness of neuro causes - ~40% of cases 02 Mayo Clinic review of Capgras - only 2/47 (4%) psychiatric! (Joseph, Arch Neuro)
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  • Anatomy of Delusions: Bifrontal & Right Hemisphere R hem plus bifrontal - post-traumatic Capgras Benson et al, 1976 Alexander et al, 1979 Delusions after R stroke (Levine & Grek, 1984) 9 patients - reduplication of place, distortions/condensations of events Tendency for frontal & temporal Most significant finding was baseline atrophy 2 HIT: R focal on diffuse Faulty reasoning and memory Misrepresentations of past events
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  • Reduplicative Paramnesia 1903 - first described by Pick as a memory disorder A place simultaneously exists in two or more physical locations Unfamiliar place (hospital) is in home town Associated with R hemisphere dysfunction Benson et al 1976 & Ruff & Volpe, 1981. RHDamage BHDamage LHDamage (Feinberg, 1989) 36 (52%) 28 (41%) 5 (7%)
  • Dj vu: Familiarity & The Temporal Lobe Dj vu transient feeling of familiarity Too brief to be a delusion, yet if it persisted Dj vu - temporal lobe foci, R>L
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  • Familiarity & The Temporal Lobe Lesions outside the right temporal lobe may cause non-delusional hyperfamiliarity syndromes by disinhibiting emotional familiarity Lesions that destroy or disconnect the right perirhinal cortex may impair familiarity
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  • Capgras and Dementia Mayo clinic - 10 year review of Capgras and misidentification 47 cases; 37 (81%) had a degenerative disorder (mean age 72 yo) vs those without (51 yo) Visual hallucinations - 30/38 with degenerative vs 2/9 (p=0.03) without Lewy Body Disease - 26 patients!
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  • Capgras & Lewy Body Disease? Lewy Body Disease Progressive cognitive decline, often frontal fxn Marked fluctuations in alertness and attention Parkinsonian motor syndromes (decreased spontaneity, rigidity) Visual hallucinations - correlates with Lewy Bodies in amygdala, parahippocampal and inferior temporal cortices Two key hits Face and emotional recognition Impaired self-monitoring to detect errors
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  • Hyperfamiliarity Patient 1 - left lateral temporal venous infarct & GTC - prosopaganoisa selectively affecting unfamiliar faces. (Vuileumier, 2003) Patient 2 32 yo man, bilateral F-T epilepsy, cluster of >10 CPS, hyperfamiliarity for faces lasting ~48 hrs Patient GP - 46 yo policeman. Dj vu, fear for 6 mos. CPS & single GTC. Since then hyperfamiliarity for faces.
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  • Hyperfamiliarity Seven patients reported All had TCS or epilepsy Most with Left hemisphere or bilateral pathology, usually affecting temporal lobe Dj vu and HFF result from increased activity in right relative to the left medial temporal lobe areas, consistent with the dominant role of the right medial temporal regions in familiarity experiences
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  • Frontal Pathology in Delusions (Feinberg et al, 2005) 29 patients with misidentification- reduplication syndromes Exclusively frontal lesions in 10/29 (34.5%) cases Four with right frontal Six with bifrontal lesions None had lesions sparing the frontal lobes
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  • Frontal Pathology in Delusions Nearly ubiquitous in delusions Impaired functions: theory of mind, decision and prediction making, time estimation and sequencing & working memory. Inability to monitor self and recognize and correct inaccurate memories and familiarity assessments. The resistance of delusions to change despite clear evidence that they are wrong likely reflects frontal dysfunction.
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  • Anosognosia: A Delusional Disorder? Unawareness of neurological deficit: vision (Antons syndrome) or movement (anosognosia for hemiplegia) Inability of self to recognize blindness or hemiplegia is strikingThe resistance of delusions to change despite clear evidence that they are wrong likely reflects frontal dysfunction. Often confabulate: its just bad lighting, can move fine Resists rational explanation or visual demonstration
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  • Anosognosia: A Delusional Disorder? Some patients deny ownership of their limb (asomatognosia), ? it belongs to someone else. Asomatognosia - delusion with loss of limbs relation to self: Capgras affecting the arm. Other patients personify the limb with names such as Floppy Joe or Silly Jimmy, hate the limb (misoplegia), or recognize the deficit but show no concern (anosodiaphoria). Anosognosia for hemiplegia - large R hemisphere strokes; par, front & temp lobes, insula, subcortex
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  • Corpus Callosum and Left Hemisphere in Delusions Act to disconnect more than connect Kosslyn L hem is categorical Callosotomy studies The verbal hemisphere - tends to lie Snow scene R Hem; Chicken claw L Hem L hand picked shovel, R hand picked chicken I saw a claw and I picked the chicken, and you have to clean out the chicken shed with a shovel Nude photo Oh doctoryou have some machine!
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  • The Hemispheres in Delusions Right lesions disinhibit the left hemisphere; loss of monitoring of: Reality, self-awareness, emotional familiarity, ego boundaries Disrupts relation between and monitoring psychic, emotional, and physical self to people, places and even body parts Excess lying & categorical thinking Left hemisphere is the delusional hemisphere.