Iktale Magnetoenzephalographie (MEG) und modernste multimodale Diagnostik führen zur Operationsindikation nach 40 Jahren pharmakorefraktärem Verlauf einer scheinbar kryptogenen Frontallappenepilepsie

Author： Bast Thomas

Publisher： Springer Publishing Company

ISSN： 1617-6782

Source： Zeitschrift für Epileptologie, Vol.20, Iss.1, 2007-02, pp. : 41-48

Disclaimer: Any content in publications that violate the sovereignty, the constitution or regulations of the PRC is not accepted or approved by CNPIEC.

Previous Menu Next

Abstract

MEG is still rarely used for presurgical epilepsy evaluations. We report the case of a 51-year-old male patient suffering from frontal lobe epilepsy. MEG revealed the first convincing localizing hint in this case whose epilepsy had previously been considered to be cryptogenic.From its onset at age 9 years, the patient's epilepsy remained drug-resistant with up to 40 seizures per day despite having tried the use of more than 15 anticonvulsants. Simple partial seizures with epigastric auras, tonic and mild hypermotor symptoms were attributed to the frontal lobe mainly due to the high seizure frequency and the short seizure duration. However, no constant clinical lateralization signs were present. All interictal EEG recordings were normal over the years. Several long-term video EEGs were recorded. Ictal EEG patterns preceded the clinical onset but showed mostly generalized flattening. Ictal bifrontal 20-25 Hz beta activity had a left hemisphere preponderance only in a few instances. High-resolution MRI showed diffuse cerebral atrophy including both hippocampi and diffuse white matter changes in both hemispheres. Focal cortical dysplasia (FCD) within the left frontal lobe was suspected but not confirmed.Only diffuse white matter changes dominated a first morphometric analysis of a high-resolution MPRAGE 3D-MRI. Interictal FDG-PET detected a hypometabolism in the right mesiotemporal lobe. Simultaneous 122-channel MEG and 32-channel EEG were recorded in November 2004 in Heidelberg. No interictal spikes were detected. A typical seizure was recorded and no lateralized EEG pattern was found. In contrast, a focal beta pattern within the right frontal lobe and bilateral propagation was identified by MEG. Source analysis revealed a localization near the right-sided medial frontal sulcus. Because of MEG findings, diagnostic work-up was reinitiated. A suspect region revealed by the prior morphometric MRI analysis corresponded to the functional abnormality and was newly interpreted as FCD. Interictal SPECT was discordant because of left temporal hypoperfusion, but ictal hyperperfusion agreed well with the MEG result. Finally, the meanwhile installed 3-Tesla MRI revealed a focal lesion indicative for FCD in the area of the known pathologic findings. Lesionectomy was guided by ECoG in July 2005 and histopathology revealed a FCD with balloon cells. The patient remained seizure free postoperatively with a follow-up of 16 months.