Assessment of working memory in patients with mesial temporal lobe epilepsy associated with unilateral hippocampal sclerosis

Abstract

In this study we did not detect reliable working memory impairment in patients with MTLE-HS with either a left or right focus in most tasks considered as tests of working memory components.

Pattern changes of EEG oscillations and BOLD signals associated with temporal lobe epilepsy as revealed by a working memory task

“…This finding is in agreement with Tudesco et al (2010) [43], who did not detect WM deficits in patients with MTLE associated with HS by means of classic neuropsychological evaluation.…”

Neocortical-hippocampal dynamics of working memory in healthy and diseased brain states based on functional connectivity

“…Given that distinct sensory inputs arrive to specific regions of the MTL in virtue of their differential connectivity pathways (Rolls, 2000), stimulus class effects in the pattern functional connectivity of different MTL regions (i.e., perirhinal and parahippocampal cortex) should be explored in future experiments (Witter et al, 2000; Davachi, 2006; Olsen et al, 2009). The compelling evidence provided by the studies we have reviewed about the involvement of MTL in WM should be reconciled with several demonstrations of WM-LTM dissociation and insensitivity of WM performance to hippocampal damage (Vallar and Papagano, 1986; Carlesimo et al, 2001; Shrager et al, 2008; Tudesco Ide et al, 2010; Jeneson et al, 2011). Further research about of WM-LTM interplay and the role of MTL will be needed.…”

“…Findings from these investigations have delineated a remarkable consistent group of areas that contribute to WM processes, this is, prefrontal cortex (PFC) (Goldman-Rakic, 1995; Braver et al, 1997; Rypma and D'Esposito, 1999; D'Esposito et al, 2000), neocortical associative areas (Druzgal and D'Esposito, 2001; Postle et al, 2003; Fiebach et al, 2007), and more recently the medial temporal lobes (MTL) (Abrahams et al, 1999; Campo et al, 2005a,b, 2009; Carrozzo et al, 2005; Karlsgodt et al, 2005; Nichols et al, 2006; Olson et al, 2006; Petersson et al, 2006; Axmacher et al, 2007, 2008a; Braun et al, 2008; Cashdollar et al, 2009; Olsen et al, 2009; Schon et al, 2009; Wagner et al, 2009; Öztekin et al, 2010; Toepper et al, 2010; van Vugt et al, 2010; Faraco et al, 2011; Lee and Rudebeck, 2011). Although the involvement of MTL in WM is matter of debate (Talmi et al, 2005; Zarahn et al, 2005; Shrager et al, 2008; Tudesco Ide et al, 2010; Jeneson et al, 2011), it has called for a re-evaluation of the prevailing conception considering that MTL is exclusively dedicated to long-term memory (LTM). These findings have reactivated the proposal of proceduralist or unitary models of memory, according to which there is a continuum between WM and LTM.…”

Concomitant Fractional Anisotropy and Volumetric Abnormalities in Temporal Lobe Epilepsy: Cross-Sectional Evidence for Progressive Neurologic Injury

“…It is therefore likely that the aetiology of differences in brain degeneration between patients with left and right TLEhs is based on a combination of architectural, connectivity, physiological and developmental differences between the hemispheres. Regardless of the causes of these differences, patients with left TLEhs consistently perform worse on neuropsychological tests that do not solely rely on the ipsilateral temporal lobe or even the ipsilateral cerebral hemisphere relative to their right-sided counterparts [84]. This may not necessarily be explained by lateralized damage to the language-dominant hemisphere, but perhaps by the fact that left TLEhs is associated with a diffuse and bilateral distribution of grey and white matter degeneration, whereas right TLEhs is associated with more restricted ipsilateral alterations.…”