Patients with extratemporal lobe epilepsy do not differ from healthy subjects with respect to subcortical volumes.
BACKGROUND
Evidence from previous volumetric magnetic resonance studies has revealed that patients with chronic temporal lobe epilepsy show atrophy of distinct subcortical nuclei, predominantly ipsilateral to the focus side. We were interested to find out if there is also selective subcortical atrophy in patients suffering from long standing extratemporal lobe epilepsy.


METHODS
Thirty one patients in whom pre-surgical evaluation unambiguously localised an extratemporal focus were included in this study. Using high resolution magnetic resonance imaging, the volumes of the caudate nuclei, putamen, pallidum, and thalamus were measured bilaterally in both hemispheres and compared with measurements obtained in 15 healthy volunteers.


RESULTS
No significant difference in volumes was found between the two subject groups, or in any subgroup of extratemporal lobe epilepsy patients, nor was there any relation to clinical variables such as age of onset, overall seizure frequency, or disease duration. However, patients who had no or only rare generalised tonic-clonic seizures seemed to differ from the other patients and controls in that they had smaller putamen volumes bilaterally (p<0.001).


CONCLUSIONS
We concluded that extratemporal lobe epilepsy in general is not associated with diminished volumes in the studied subcortical structures, which contrasts with findings in temporal lobe epilepsy patients. Thus, both entities differ both cortically and subcortically. However, we found that small putamen volume was bilaterally associated with absent or rare generalised tonic-clonic seizures, implicating the putamen in the control of the most disabling seizure type, independent of the site of neocortical focus.
Gärtner
B
B
Laboratory of Presurgical Epilepsy Evaluation, Functional Neurology and Neurosurgery Program of the University Hospitals Lausanne and Geneva, Department of Neurology, 24 rue Micheli-du-Crest, 1211 Geneva 4, Switzerland.
Seeck
M
M
Michel
C M
CM
Delavelle
J
J
Lazeyras
F
F
D000328:Adult; D001284:Atrophy; D001921:Brain / Q000473:pathology*; D002421:Caudate Nucleus / Q000473:pathology; D002540:Cerebral Cortex / Q000473:pathology; D004292:Dominance, Cerebral / Q000502:physiology; D004828:Epilepsies, Partial / Q000175:diagnosis* / Q000209:etiology; D017034:Epilepsy, Frontal Lobe / Q000175:diagnosis* / Q000209:etiology / Q000601:surgery; D004829:Epilepsy, Generalized / Q000175:diagnosis* / Q000209:etiology / Q000601:surgery; D004833:Epilepsy, Temporal Lobe / Q000175:diagnosis* / Q000601:surgery; D004830:Epilepsy, Tonic-Clonic / Q000175:diagnosis* / Q000209:etiology / Q000601:surgery; D005260:Female; D005917:Globus Pallidus / Q000473:pathology; D006624:Hippocampus / Q000473:pathology; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D009434:Neural Pathways / Q000473:pathology; D010296:Parietal Lobe / Q000473:pathology; D011183:Postoperative Complications / Q000175:diagnosis; D011699:Putamen / Q000473:pathology; D012016:Reference Values; D013788:Thalamus / Q000473:pathology