Assessing awareness in severe Alzheimer's disease
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Published version
Author(s)
Type
Journal Article
Abstract
There is an urgent need to understand the nature of awareness in people with severe Alzheimer’s disease (AD) to ensure effective person-centered care. Objective biomarkers of awareness validated in other clinical groups (e.g., anesthesia, minimally conscious states) offer an opportunity to investigate awareness in people with severe AD. In this article we demonstrate the feasibility of using Transcranial magnetic stimulation (TMS) combined with EEG, event related potentials (ERPs) and fMRI to assess awareness in severe AD. TMS-EEG was performed in six healthy older controls and three people with severe AD. The perturbational complexity index (PCIST) was calculated as a measure of capacity for conscious awareness. People with severe AD demonstrated a PCIST around or below the threshold for consciousness, suggesting reduced capacity for consciousness. ERPs were recorded during a visual perception paradigm. In response to viewing faces, two patients with severe AD provisionally demonstrated similar visual awareness negativity to healthy controls. Using a validated fMRI movie-viewing task, independent component analysis in two healthy controls and one patient with severe AD revealed activation in auditory, visual and fronto-parietal networks. Activation patterns in fronto-parietal networks did not significantly correlate between the patient and controls, suggesting potential differences in conscious awareness and engagement with the movie. Although methodological issues remain, these results demonstrate the feasibility of using objective measures of awareness in severe AD. We raise a number of challenges and research questions that should be addressed using these biomarkers of awareness in future studies to improve understanding and care for people with severe AD.
Date Issued
2023-02-01
Date Acceptance
2022-12-30
Citation
Frontiers in Human Neuroscience, 2023, 16
ISSN
1662-5161
Publisher
Frontiers Media S.A.
Journal / Book Title
Frontiers in Human Neuroscience
Volume
16
Copyright Statement
© 2023 Huntley, Bor, Deng, Mancuso, Mediano,
Naci, Owen, Rocchi, Sternin and Howard. 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) and the
copyright owner(s) 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.
Naci, Owen, Rocchi, Sternin and Howard. 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) and the
copyright owner(s) 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.
License URL
Identifier
https://www.frontiersin.org/journals/human-neuroscience/articles/10.3389/fnhum.2022.1035195/full
Subjects
ACCESS
awareness
CONSCIOUS EXPERIENCES
consciousness
EEG
fMRI
FMRI
Life Sciences & Biomedicine
Neurosciences
Neurosciences & Neurology
PEOPLE
PERSON-CENTERED CARE
Psychology
SCALE
Science & Technology
SEVERE DEMENTIA
Social Sciences
STATE
TMS
Publication Status
Published
Article Number
1035195
Date Publish Online
2023-02-01