Neural correlates of de novo depression following left temporal lobe epilepsy surgery: a voxel based morphometry study of pre-surgical structural MRI.
OBJECTIVE
To investigate cerebral grey matter (GM) volumetric abnormalities in temporal lobe epilepsy (TLE) patients who develop de novo depression following TLE surgery using voxel-based morphometry (VBM).


METHODS
We retrospectively examined pre-surgical grey matter (GM) volumes in 30 patients with TLE due to unilateral left-sided hippocampal sclerosis using 1.5-T MRI scan, which were segmented with optimised VBM parameters and normalised to a sample template using DARTEL, with SPM8 software. Voxel-wise GM differences between patients that developed de novo post-surgical depression (n=5) were compared with patients with no pre- or postoperative psychiatric diagnoses (n=25), using independent samples t-tests with age, gender and secondary generalised tonic-clonic seizures (SGTCS) as covariates (p<.001, unc).


RESULTS
Reduced preoperative bilateral GM in orbitofrontal cortices (OFC) and ipsilateral cingulate gyrus and thalamus were significantly associated with the development of de novo depression within 4 years postoperatively. Further analyses revealed no differences in seizure freedom (ILAE 1 vs 2-6) or postoperative memory decline between the groups.


CONCLUSIONS
Although the development of postoperative de novo depression following TLE surgery is likely to be multi-factorial, our results suggest that bilateral OFC and ipsilateral cingulate gyrus and thalamic atrophy in left-sided TLE patients may play a modulatory role. Abnormalities in these areas have also been implicated in primary mood disorders. Prospective neuroimaging studies with larger cohorts are warranted to replicate these results, and further elucidate the neural correlates of de novo depression.
Institute of Neurology, Department of Clinical and Experimental Epilepsy, University College London, Queen Square, London SL9 0RJ, UK; Wellcome Trust Centre for Neuroimaging, Institute of Neurology, University College London, 12 Queen Square, London WC1N 3BG, UK. Electronic address: r.pope@ucl.ac.uk.
Rebecca Anne
RA
Pope
Institute of Neurology, Department of Clinical and Experimental Epilepsy, University College London, Queen Square, London SL9 0RJ, UK; Institute of Child Health, University College London, London WC1N 1EH, UK.
Maria
M
Centeno
Department of Neurology, Kantonsspital St. Gallen, Switzerland.
Dominique
D
Flügel
Institute of Neurology, Department of Clinical and Experimental Epilepsy, University College London, Queen Square, London SL9 0RJ, UK.
Mark Robert
MR
Symms
Institute of Neurology, Department of Clinical and Experimental Epilepsy, University College London, Queen Square, London SL9 0RJ, UK; The National Hospital for Neurology and Neurosurgery, Queen Square, London WC1N 2BG, UK.
Matthias
M
Koepp
Institute of Neurology, Department of Clinical and Experimental Epilepsy, University College London, Queen Square, London SL9 0RJ, UK; The National Hospital for Neurology and Neurosurgery, Queen Square, London WC1N 2BG, UK.
Pamela Jane
PJ
Thompson
Institute of Neurology, Department of Clinical and Experimental Epilepsy, University College London, Queen Square, London SL9 0RJ, UK; The National Hospital for Neurology and Neurosurgery, Queen Square, London WC1N 2BG, UK.
Jacqueline
J
Foong
D000328:Adult; D038481:Anterior Temporal Lobectomy / Q000009:adverse effects*; D001931:Brain Mapping; D016009:Chi-Square Distribution; D003863:Depression / Q000209:etiology*; D004833:Epilepsy, Temporal Lobe / Q000150:complications / Q000473:pathology / Q000601:surgery*; D056344:Executive Function / Q000502:physiology; D005260:Female; D007839:Functional Laterality / Q000502:physiology*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008569:Memory Disorders / Q000209:etiology; D009483:Neuropsychological Tests; D011183:Postoperative Complications / Q000473:pathology* / Q000503:physiopathology; D011569:Psychiatric Status Rating Scales; D055815:Young Adult
Epilepsy surgery; Neuroimaging; Neuropsychiatry; Neuropsychology; Temporal lobe epilepsy