False recognition in behavioral variant frontotemporal dementia and Alzheimer's Disease - Disinhibition or amnesia?

Flanagan, Emma C., Wong, Stephanie, Dutt, Aparna, Tu, Sicong, Bertoux, Maxime, Irish, Muireann, Piguet, Olivier, Rao, Sulakshana, Hodges, John R., Ghosh, Amitabha and Hornberger, Michael (2016) False recognition in behavioral variant frontotemporal dementia and Alzheimer's Disease - Disinhibition or amnesia? Frontiers in Aging Neuroscience, 8. ISSN 1663-4365

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Abstract

Episodic memory recall processes in Alzheimer's disease (AD) and behavioral variant frontotemporal dementia (bvFTD) can be similarly impaired, whereas recognition performance is more variable. A potential reason for this variability could be false-positive errors made on recognition trials and whether these errors are due to amnesia per se or a general over-endorsement of recognition items regardless of memory. The current study addressed this issue by analysing recognition performance on the Rey Auditory Verbal Learning Test (RAVLT) in 39 bvFTD, 77 AD and 61 control participants from two centers (India, Australia), as well as disinhibition assessed using the Hayling test. Whereas both AD and bvFTD patients were comparably impaired on delayed recall, bvFTD patients showed intact recognition performance in terms of the number of correct hits. However, both patient groups endorsed significantly more false-positives than controls, and bvFTD and AD patients scored equally poorly on a sensitivity index (correct hits—false-positives). Furthermore, measures of disinhibition were significantly associated with false positives in both groups, with a stronger relationship with false-positives in bvFTD. Voxel-based morphometry analyses revealed similar neural correlates of false positive endorsement across bvFTD and AD, with both patient groups showing involvement of prefrontal and Papez circuitry regions, such as medial temporal and thalamic regions, and a DTI analysis detected an emerging but non-significant trend between false positives and decreased fornix integrity in bvFTD only. These findings suggest that false-positive errors on recognition tests relate to similar mechanisms in bvFTD and AD, reflecting deficits in episodic memory processes and disinhibition. These findings highlight that current memory tests are not sufficient to accurately distinguish between bvFTD and AD patients.

Item Type: Article
Additional Information: Copyright © 2016 Flanagan, Wong, Dutt, Tu, Bertoux, Irish, Piguet, Rao, Hodges, Ghosh and Hornberger. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
Uncontrolled Keywords: frontotemporal dementia,alzheimer’s disease,memory,recognition,disinhibition
Faculty \ School: Faculty of Medicine and Health Sciences > Norwich Medical School
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Depositing User: Pure Connector
Date Deposited: 24 Sep 2016 00:13
Last Modified: 22 Jul 2020 00:59
URI: https://ueaeprints.uea.ac.uk/id/eprint/59923
DOI: 10.3389/fnagi.2016.00177

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