Widespread functional deficits in perception-related networks demonstrated by PET in a case with simple visual seizures.
OBJECTIVE
To study benzodiazepine receptor (BZR) density and functional deficits in occipital lobe epilepsy.


METHODS
A 39-year-old man who had simple partial visual seizures after neurosurgical transtentorial extirpation of a pinealoma was studied by EEG, magnetic resonance imaging (MRI), and positron emission tomography (PET) of [18F]2-fluoro-2-deoxy-D-glucose (FDG) at rest and during visual activation task and[11C]flumazenil (FMZ).


RESULTS
Electroencephalographic recordings were nonspecific, and MRI did not reveal any morphologic anomaly in the occipital lobe. Flumazenil-PET demonstrated a small epileptogenic region in the right visual association cortex and FDG-PET showed hypometabolism in a corresponding location and thalamic diaschisis. Stimulation of occipital metabolism by a continuous visual recognition task improved significantly the contrast between the dysfunctional zone and its surround.


CONCLUSIONS
As BZR deficits are restricted to a small region, widespread hypometabolism in networks involved in visual information processing indicates an extensive functional deactivation by the epileptogenic focus.
Mielke
R
R
Max-Planck-Institut für Neurologische Forschung und Universitätsklinik für Neurologie, Köln, Germany.
Weber-Luxenburger
G
G
Kessler
J
J
Szelies
B
B
Heiss
W D
WD
D000328:Adult; D002250:Carbon Radioisotopes; D003847:Deoxyglucose / Q000031:analogs & derivatives; D004569:Electroencephalography; D004828:Epilepsies, Partial / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000378:metabolism / Q000503:physiopathology; D005260:Female; D005442:Flumazenil; D019788:Fluorodeoxyglucose F18; D007839:Functional Laterality; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D009778:Occipital Lobe / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology*; D011963:Receptors, GABA-A / Q000737:chemistry / Q000378:metabolism; D013788:Thalamus / Q000000981:diagnostic imaging / Q000378:metabolism; D014055:Tomography, Emission-Computed; D014793:Visual Cortex / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology; D014795:Visual Pathways / Q000000981:diagnostic imaging / Q000378:metabolism*
D002250:Carbon Radioisotopes; D011963:Receptors, GABA-A; D019788:Fluorodeoxyglucose F18; D005442:Flumazenil; D003847:Deoxyglucose