title: Incipient preoperative reorganization processes of verbal memory functions in patients with left temporal lobe epilepsy.
abstract: We previously reported nonlinear correlations between verbal episodic memory performance and BOLD signal in memory fMRI in healthy subjects. The purpose of the present study was to examine this observation in patients with left mesial temporal lobe epilepsy (mTLE) who often experience memory decline and need reliable prediction tools before epilepsy surgery with hippocampectomy. Fifteen patients with left mTLE (18-57years, nine females) underwent a verbal memory fMRI paradigm. Correlations between BOLD activity and neuropsychological data were calculated for the i) hippocampus (HC) as well as ii) extrahippocampal mTL structures. Memory performance was systematically associated with activations within the right HC as well as with activations within the left extrahippocampal mTL regions (amygdala and parahippocampal gyrus). As hypothesized, the analyses revealed cubic relationships, with one peak in patients with marginal memory performance and another peak in patients with very good performance. The nonlinear correlations between memory performance and activations might reflect the compensatory recruitment of neural resources to maintain memory performance in patients with ongoing memory deterioration. The present data suggest an already incipient preoperative reorganization process of verbal memory in non-amnesic patients with left mTLE by simultaneously tapping the resources of the right HC and left extrahippocampal mTL regions. Thus, in the preoperative assessment, both neuropsychological performance and memory fMRI should be considered together.
authors.affiliation: Department of Neurosurgery, University of Tuebingen, Tuebingen, Germany.
authors.forename: Monika
authors.initials: M
authors.lastname: Milian
authors.affiliation: Department of Vascular Neurology, University of Tuebingen, Tuebingen, Germany.
authors.forename: Lena
authors.initials: L
authors.lastname: Zeltner
authors.affiliation: Department of Biomedical Magnetic Resonance, University of Tuebingen, Tuebingen, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Erb
authors.affiliation: Department of Neuroradiology, University of Tuebingen, Tuebingen, Germany.
authors.forename: Uwe
authors.initials: U
authors.lastname: Klose
authors.affiliation: Epilepsy Center, University Hospital Freiburg, Germany.
authors.forename: Kathrin
authors.initials: K
authors.lastname: Wagner
authors.affiliation: Center of Geriatrics and Gerontology Freiburg, University Hospital Freiburg, Germany.
authors.forename: Lars
authors.initials: L
authors.lastname: Frings
authors.affiliation: Department of Biomedical Magnetic Resonance, University of Tuebingen, Tuebingen, Germany.
authors.forename: Cornelia
authors.initials: C
authors.lastname: Veil
authors.affiliation: Department of Neurosurgery, University of Tuebingen, Tuebingen, Germany.
authors.forename: Sabine
authors.initials: S
authors.lastname: Rona
authors.affiliation: Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tuebingen, Tuebingen, Germany.
authors.forename: Holger
authors.initials: H
authors.lastname: Lerche
authors.affiliation: Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tuebingen, Tuebingen, Germany. Electronic address: silke.klamer@uni-tuebingen.de.
authors.forename: Silke
authors.initials: S
authors.lastname: Klamer
mesh_terms: D000293:Adolescent; D000328:Adult; D000679:Amygdala / Q000503:physiopathology*; D004833:Epilepsy, Temporal Lobe / Q000503:physiopathology*; D005260:Female; D006624:Hippocampus / Q000503:physiopathology*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008568:Memory / Q000502:physiology*; D008875:Middle Aged; D020534:Parahippocampal Gyrus / Q000503:physiopathology*; D057234:Preoperative Period; D055815:Young Adult
keywords: Chronic mesial temporal lobe epilepsy; Hippocampus; Memory fMRI; Nonlinear correlations; Preoperative reorganization