Sunday, June 13, 2010

Hyperfamiliarity for faces (HFF) in epilepsy- left temporal localization?

Devinsky O  et al.  Neurology 2010;74: 970-974

Author reviews literature and attributes the first case to Kraepelin (1886).

Case one-- 46 yo policeman had a GTCS preceded by an aura of anxiety, deja vu and sulfuric smell. One month later the patient developed HFF (everyone seemed familiar), memory problems, distractibility and hyperemotionality for sadness.  FRT performance was low average but patient was impaired on Rey O delayed recall.

Case 2-  62 yo rh attorney developed CPS at age 31 with sense of doom, palpitations and nightmares.  Seizures involved HFF,

table has 2 more new cases and 5 old cases

Pertinent facts about HFF- specifically absent are delusions, hyperfamiliarity for nonface objects, or auditory hallucinations.  Lesions involved left hemisphere (5 cases), bilateral (2 cases) or unknown (2 cases). 

Authors cite that the hippocampus is important for recollection and the perirhinal cortex for feeling of familiarity.  Deja vu and deja vecu occur more often with right hemisphere lesions establishing "right sided dominance for familiarity."  The normal electrical response for familiarity is suppression v. activation for novelty stimulus.  Authors speculate the left (impaired) side is unable to recognize faces (nvelty signallig) whereas the right (unipaired) side is in overdrive and falsely signal familiarity. Patients quickly accept their familiarity is false, due to intact right hemisphere structures otherwise.   Contrtast to reduplication syndromes (Capgras) with right hemispheric and bifrontal abnormality. 

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