The anatomical bases of semantic retrieval deficits in early Alzheimer's disease

TY - JOUR

T1 - The anatomical bases of semantic retrieval deficits in early Alzheimer's disease

AU - Venneri, Annalena

AU - McGeown, William J.

AU - Hietanen, Heidi M.

AU - Guerrini, Chiara

AU - Ellis, Andrew W.

AU - Shanks, Michael F.

PY - 2008

Y1 - 2008

N2 - Semantic abilities deteriorate early inpatients with Alzheimer's disease (AD) and their residual language is characterised by strong lexical effects such as the age of acquisition of words and their typicality. The anatomical bases of this early semantic degradation have not been fully explored. To clarify which neural structures, when atrophic, alter lexical-semantic function in patients with very mild AD, this study correlated the lexical attributes of words produced in a semantic fluency task with grey matter density values from 3D MRI scans of mild AD patients. The voxel-based analyses showed a significant correlation between the lexical attributes characterising residual linguistic production in early AD patients and the integrity of regions of the medial temporal lobes, especially in areas of the perirhinal and parahippocampal cortex. This correlation was present in both hemispheres. There were no correlations within these structures with scores on neuropsychological tests not involving semantic or episodic memory. The results have implications for the role of medial temporal structures in episodic and semantic retrieval and argue against a unitary function of these structures in respect of episodic and semantic memory processes. This evidence suggests that specialised regions within the hippocampal complex engage in processes of encoding and retrieval for both semantic and episodic memories. (C) 2007 Elsevier Ltd. All rights reserved.

AB - Semantic abilities deteriorate early inpatients with Alzheimer's disease (AD) and their residual language is characterised by strong lexical effects such as the age of acquisition of words and their typicality. The anatomical bases of this early semantic degradation have not been fully explored. To clarify which neural structures, when atrophic, alter lexical-semantic function in patients with very mild AD, this study correlated the lexical attributes of words produced in a semantic fluency task with grey matter density values from 3D MRI scans of mild AD patients. The voxel-based analyses showed a significant correlation between the lexical attributes characterising residual linguistic production in early AD patients and the integrity of regions of the medial temporal lobes, especially in areas of the perirhinal and parahippocampal cortex. This correlation was present in both hemispheres. There were no correlations within these structures with scores on neuropsychological tests not involving semantic or episodic memory. The results have implications for the role of medial temporal structures in episodic and semantic retrieval and argue against a unitary function of these structures in respect of episodic and semantic memory processes. This evidence suggests that specialised regions within the hippocampal complex engage in processes of encoding and retrieval for both semantic and episodic memories. (C) 2007 Elsevier Ltd. All rights reserved.

KW - semantic retrieval

KW - perithinal

KW - Alzheimer's disease

KW - category fluency

KW - voxel-based morphometry

KW - MILD COGNITIVE IMPAIRMENT

KW - PRIMARY PROGRESSIVE APHASIA

KW - VOXEL-BASED MORPHOMETRY

KW - VERBAL FLUENCY TASK

KW - TEMPORAL-LOBE

KW - INTERNATIONAL WORKSHOP

KW - MEMORY CONSOLIDATION

KW - PICTURE DESCRIPTION

KW - RETROGRADE-AMNESIA

KW - LINGUISTIC ABILITY

UR - http://www.scopus.com/inward/record.url?scp=38749089791&partnerID=8YFLogxK

U2 - 10.1016/j.neuropsychologia.2007.08.026

DO - 10.1016/j.neuropsychologia.2007.08.026

M3 - Article

VL - 46

SP - 497

EP - 510

JO - Neuropsychologia

JF - Neuropsychologia

SN - 0028-3932

IS - 2

ER -