Correlation between topographic N400 anomalies and reduced cerebral blood flow in the anterior temporal lobes of patients with dementia

Grieder, Matthias; Crinelli, Raffaella M; Jann, Kay; Federspiel, Andrea; Wirth, Miranka; Koenig, Thomas; Stein, Maria; Wahlund, Lars-Olof; Dierks, Thomas (2013). Correlation between topographic N400 anomalies and reduced cerebral blood flow in the anterior temporal lobes of patients with dementia. Journal of Alzheimer's disease, 36(4), pp. 711-731. Amsterdam: IOS Press 10.3233/JAD-121690

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In Alzheimer's disease (AD) patients, episodic memory impairments are apparent, yet semantic memory difficulties are also observed. While the episodic pathology has been thoroughly studied, the neurophysiological mechanisms of the semantic impairments remain obscure. Semantic dementia (SD) is characterized by isolated semantic memory deficits. The present study aimed to find an early marker of mild AD and SD by employing a semantic priming paradigm during electroencephalogram recordings. Event-related potentials (ERP) of early (P1, N1) and late (N400) word processing stages were obtained to measure semantic memory functions. Separately, baseline cerebral blood flow (CBF) was acquired with arterial spin labeling. Thus, the analysis focused on linear regressions of CBF with ERP topographical similarity indices in order to find the brain structures that showed altered baseline functionality associated with deviant ERPs. All participant groups showed semantic priming in their reaction times. Furthermore, decreased CBF in the temporal lobes was associated with abnormal N400 topography. No significant CBF clusters were found for the early ERPs. Taken together, the neurophysiological results suggested that the automatic spread of activation during semantic word processing was preserved in mild dementia, while controlled access to the words was impaired. These findings suggested that N400-topography alterations might be a potential marker for the detection of early dementia. Such a marker could be beneficial for differential diagnosis due to its low cost and non-invasive application as well as its relationship with semantic memory dysfunctions that are closely associated to the cortical deterioration in regions crucial for semantic word processing.

Item Type:	Journal Article (Original Article)
Division/Institute:	04 Faculty of Medicine > University Psychiatric Services > University Hospital of Psychiatry and Psychotherapy > Psychiatric Neurophysiology [discontinued]
UniBE Contributor:	Grieder, Matthias, Jann, Kay, Federspiel, Andrea, Wirth, Miranka, König, Thomas, Stein, Maria, Dierks, Thomas
ISSN:	1387-2877
Publisher:	IOS Press
Language:	English
Submitter:	Factscience Import
Date Deposited:	04 Oct 2013 14:39
Last Modified:	05 Dec 2022 14:12
Publisher DOI:	10.3233/JAD-121690
PubMed ID:	23666175
Web of Science ID:	000322738000009
URI:	https://boris.unibe.ch/id/eprint/15793 (FactScience: 223246)