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Temporal lobe epilepsy in patients with nonlesional MRI and normal memory: an SEEG study.
J Neurosurg 2015; 123(6):1368-74JN

Abstract

OBJECT

Temporal lobe epilepsy (TLE) in the absence of MRI abnormalities and memory deficits is often presumed to have an extramesial or even extratemporal source. In this paper the authors report the results of a comprehensive stereoelectroencephalography (SEEG) analysis in patients with TLE with normal MRI images and memory scores.

METHODS

Eighteen patients with medically refractory epilepsy who also had unremarkable MR images and normal verbal and visual memory scores on neuropsychological testing were included in the study. All patients had seizure semiology and video electroencephalography (EEG) findings suggestive of TLE. A standardized SEEG investigation was performed for each patient with electrodes implanted into the mesial and lateral temporal lobe, temporal tip, posterior temporal neocortex, orbitomesiobasal frontal lobe, posterior cingulate gyrus, and insula. This information was used to plan subsequent surgical management.

RESULTS

Interictal SEEG abnormalities were observed in the mesial temporal structures in 17 patients (94%) and in the temporal tip in 6 (33%). Seizure onset was exclusively from mesial structures in 13 (72%), exclusively from lateral temporal cortex and/or temporal tip structures in 2 (11%), and independently from mesial and neocortical foci in 3 (17%). No seizure activity was observed arising from any extratemporal location. All patients underwent surgical intervention targeting the temporal lobe and tailored to the SEEG findings, and all experienced significant improvement in seizure frequency with a postoperative follow-up observation period of at least 1 year.

CONCLUSIONS

This study demonstrates 3 important findings: 1) normal memory does not preclude mesial temporal seizure onset; 2) onset of seizures exclusively from mesial temporal structures without early neocortical involvement is common, even in the absence of memory deficits; and 3) extratemporal seizure onset is rare when video EEG and semiology are consistent with focal TLE.

Authors+Show Affiliations

The Neurological Institute, University Hospital Case Medical Center, Case Western Reserve University School of Medicine, Cleveland, Ohio.The Neurological Institute, University Hospital Case Medical Center, Case Western Reserve University School of Medicine, Cleveland, Ohio.The Neurological Institute, University Hospital Case Medical Center, Case Western Reserve University School of Medicine, Cleveland, Ohio.The Neurological Institute, University Hospital Case Medical Center, Case Western Reserve University School of Medicine, Cleveland, Ohio.The Neurological Institute, University Hospital Case Medical Center, Case Western Reserve University School of Medicine, Cleveland, Ohio.The Neurological Institute, University Hospital Case Medical Center, Case Western Reserve University School of Medicine, Cleveland, Ohio.

Pub Type(s)

Journal Article

Language

eng

PubMed ID

26207602

Citation

Suresh, Suraj, et al. "Temporal Lobe Epilepsy in Patients With Nonlesional MRI and Normal Memory: an SEEG Study." Journal of Neurosurgery, vol. 123, no. 6, 2015, pp. 1368-74.
Suresh S, Sweet J, Fastenau PS, et al. Temporal lobe epilepsy in patients with nonlesional MRI and normal memory: an SEEG study. J Neurosurg. 2015;123(6):1368-74.
Suresh, S., Sweet, J., Fastenau, P. S., Lüders, H., Landazuri, P., & Miller, J. (2015). Temporal lobe epilepsy in patients with nonlesional MRI and normal memory: an SEEG study. Journal of Neurosurgery, 123(6), pp. 1368-74. doi:10.3171/2015.1.JNS141811.
Suresh S, et al. Temporal Lobe Epilepsy in Patients With Nonlesional MRI and Normal Memory: an SEEG Study. J Neurosurg. 2015;123(6):1368-74. PubMed PMID: 26207602.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Temporal lobe epilepsy in patients with nonlesional MRI and normal memory: an SEEG study. AU - Suresh,Suraj, AU - Sweet,Jennifer, AU - Fastenau,Philip S, AU - Lüders,Hans, AU - Landazuri,Patrick, AU - Miller,Jonathan, Y1 - 2015/07/24/ PY - 2015/7/25/entrez PY - 2015/7/25/pubmed PY - 2016/3/29/medline KW - EEG = electroencephalography KW - MRI-negative epilepsy KW - SEEG = stereoelectroencephalography KW - TLE = temporal lobe epilepsy KW - normal memory KW - stereoencephalography KW - temporal lobe epilepsy SP - 1368 EP - 74 JF - Journal of neurosurgery JO - J. Neurosurg. VL - 123 IS - 6 N2 - OBJECT: Temporal lobe epilepsy (TLE) in the absence of MRI abnormalities and memory deficits is often presumed to have an extramesial or even extratemporal source. In this paper the authors report the results of a comprehensive stereoelectroencephalography (SEEG) analysis in patients with TLE with normal MRI images and memory scores. METHODS: Eighteen patients with medically refractory epilepsy who also had unremarkable MR images and normal verbal and visual memory scores on neuropsychological testing were included in the study. All patients had seizure semiology and video electroencephalography (EEG) findings suggestive of TLE. A standardized SEEG investigation was performed for each patient with electrodes implanted into the mesial and lateral temporal lobe, temporal tip, posterior temporal neocortex, orbitomesiobasal frontal lobe, posterior cingulate gyrus, and insula. This information was used to plan subsequent surgical management. RESULTS: Interictal SEEG abnormalities were observed in the mesial temporal structures in 17 patients (94%) and in the temporal tip in 6 (33%). Seizure onset was exclusively from mesial structures in 13 (72%), exclusively from lateral temporal cortex and/or temporal tip structures in 2 (11%), and independently from mesial and neocortical foci in 3 (17%). No seizure activity was observed arising from any extratemporal location. All patients underwent surgical intervention targeting the temporal lobe and tailored to the SEEG findings, and all experienced significant improvement in seizure frequency with a postoperative follow-up observation period of at least 1 year. CONCLUSIONS: This study demonstrates 3 important findings: 1) normal memory does not preclude mesial temporal seizure onset; 2) onset of seizures exclusively from mesial temporal structures without early neocortical involvement is common, even in the absence of memory deficits; and 3) extratemporal seizure onset is rare when video EEG and semiology are consistent with focal TLE. SN - 1933-0693 UR - https://www.unboundmedicine.com/medline/citation/26207602/Temporal_lobe_epilepsy_in_patients_with_nonlesional_MRI_and_normal_memory:_an_SEEG_study_ L2 - http://www.diseaseinfosearch.org/result/2593 DB - PRIME DP - Unbound Medicine ER -