Assessing a Metacognitive Account of Associative Memory Impairments in Temporal Lobe Epilepsy.

Nathan A Illman,Steven Kemp,Robin G Morris,Céline Souchay,Chris J A Moulin

doi:10.1155/2016/6746938

Abstract

Previous research has pointed to a deficit in associative recognition in temporal lobe epilepsy (TLE). Associative recognition tasks require discrimination between various combinations of words which have and have not been seen previously (such as old-old or old-new pairs). People with TLE tend to respond to rearranged old-old pairs as if they are “intact” old-old pairs, which has been interpreted as a failure to use a recollection strategy to overcome the familiarity of two recombined words into a new pairing. We examined this specific deficit in the context of metacognition, using postdecision confidence judgements at test. We expected that TLE patients would show inappropriate levels of confidence for associative recognition. Although TLE patients reported lower confidence levels in their responses overall, they were sensitive to the difficulty of varying pair types in their judgements and gave significantly higher confidence ratings for their correct answers. We conclude that a strategic deficit is not at play in the associative recognition of people with TLE, insofar as they are able to monitor the status of their memory system. This adds to a growing body of research suggesting that recollection is impaired in TLE, but not metacognition.

Highlights

Temporal lobe epilepsy (TLE) is typified by episodic memory impairment
The sample was suitable for our aim of testing the hypothesis that the deficit in associative recognition would manifest itself as an inaccurate assessment of the confidence for the critical item pairs. For this reason and due to the small number of patients with left TLE (LTLE), right TLE (RTLE), and bilateral TLE (BTLE), we focus all subsequent analyses on the epilepsy group as a whole
We found no significant impairment in process dissociation procedure (PDP) derived recollection estimates in the TLE participants, our study has replicated one of the key associative deficits observed by Cohn et al an inability to retrieve associative binding information at test to differentiate intact from recombined pairs of previously studied items in an associative identification task

Summary

Introduction

Temporal lobe epilepsy (TLE) is typified by episodic memory impairment. In recent years the memory deficit has been increasingly researched in terms of the contribution of two arguably separable processes, that of recollection and that of familiarity. In the absence of intact recollection, the parallel process of familiarity may aid memory; recognition based on familiarity is done in the absence of retrieving contextual or associative information but still provides a relatively good indicator of prior exposure through a feeling of “oldness.” A number of studies have produced evidence for recollection as the locus for impairment in TLE, as established by exploring associative recognition memory [1,2,3,4,5,6,7,8] This emphasis on recollection derives from the role of the medial temporal lobe (MTL) in specific recollection processes (see [9] for a review). One recently tested idea is that some of these memory difficulties are, at least in part, metacognitive [12], that is, being related

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