Characterising subtypes of hippocampal sclerosis and reorganisation: Correlation with pre and post-operative memory deficit.

Characterising subtypes of hippocampal sclerosis and reorganisation: Correlation with pre and post-operative memory deficit.

Brain Pathol. 2017 Apr 05;:

Authors: Prada Jardim A, Liu J, Baber J, Michalak Z, Reeves C, Ellis M, Novy J, de Tisi J, McEvoy A, Miserocchi A, Targas Yacubian EM, Sisodiya S, Thompson P, Thom M

Abstract
Neuropathological subtypes of hippocampal sclerosis (HS) in temporal lobe epilepsy (2013 ILAE classification) are based on the qualitative assessment of patterns of neuronal loss with NeuN. In practice, some cases appear indeterminate between type 1 (CA1 and CA4 loss) and type 2 HS (CA1 loss) and we predicted that MAP2 would enable a more stringent classification. HS subtypes, as well as the accompanying alteration of axonal networks, regenerative capacity and neurodegeneration have been previously correlated with outcome and memory deficits and may provide prognostic clinical information. We selected 92 cases: 52 type 1 HS, 15 type 2 HS, 18 Indeterminate-HS and 7 no-HS. Quantitative analysis was carried out on NeuN and MAP2 stained sections and a labelling index (LI) calculated for six hippocampal subfields. We also evaluated hippocampal regenerative activity (MCM2, nestin, olig2, calbindin), degeneration (AT8/phosphorylated tau) and mossy-fibre pathway re-organisation (ZnT3). Pathology measures were correlated with clinical epilepsy history, memory and naming test scores and post-operative outcomes, at one year following surgery. MAP2 LI in Indeterminate-HS was statistically similar to type 2 HS but this clustering was not shown with NeuN. Moderate verbal and visual memory deficits were noted in all HS types, including 54% and 69% of type 2 HS. Memory deficits correlated with several pathology factors including lower NeuN or MAP2 LI in CA4, CA1, dentate gyrus and subiculum and poor preservation of the mossy fibre pathway. Decline in memory at one year associated with AT8 labelling in the subiculum and dentate gyrus but not HS type. We conclude that MAP2 is a helpful addition in the classification of HS in some cases. Classification of HS subtype, however, did not significantly correlate with outcome or pre or post-operative memory dysfunction, which was associated with multiple pathology factors including hippocampal axonal pathways, regenerative capacity and degenerative changes. This article is protected by copyright. All rights reserved.

PMID: 28380661 [PubMed - as supplied by publisher]

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