White Matter Deterioration May Foreshadow Impairment of Emotional Valence Determination in Early-Stage Dementia of the Alzheimer Type

Ravi Rajmohan, Department of Pharmacology and Neuroscience, Texas Tech University Health Sciences Center Lubbock, TX, USA.
Ronald C. Anderson, Department of Electrical and Computer Engineering, Texas Tech University Lubbock, TX, USA.
Dan Fang, Department of Human Development and Family Studies, Texas Tech University Lubbock, TX, USA.
Austin G. Meyer, School of Medicine, Texas Tech University Health Sciences Center Lubbock, TX, USA.
Pavis Laengvejkal, Department of Neurology, Texas Tech University Health Sciences Center Lubbock, TX, USA.
Parunyou Julayanont, Department of Neurology, Texas Tech University Health Sciences Center Lubbock, TX, USA.
Greg Hannabas, Department of Public Health, Texas Tech University Health Sciences Center Lubbock, TX, USA.
Kitten Linton, Department of Family Medicine, Texas Tech University Health Sciences Center Lubbock, TX, USA.
John Culberson, Department of Family Medicine, Texas Tech University Health Sciences Center Lubbock, TX, USA.
Hafiz M. Khan, Department of Public Health, Texas Tech University Health Sciences Center Lubbock, TX, USA.
John De Toledo, Department of Neurology, Texas Tech University Health Sciences Center Lubbock, TX, USA.
P Hemachandra Reddy, Department of Pharmacology and Neuroscience, Texas Tech University Health Sciences CenterLubbock, TX, USA; Garrison Institute on Aging, Texas Tech University Health Sciences CenterLubbock, TX, USA; Cell Biology and Biochemistry, Texas Tech University Health Sciences CenterLubbock, TX, USA; Speech, Language and Hearing Sciences, Texas Tech University Health Sciences CenterLubbock, TX, USA.
Michael O'Boyle, Department of Pharmacology and Neuroscience, Texas Tech University Health Sciences CenterLubbock, TX, USA; Department of Human Development and Family Studies, Texas Tech UniversityLubbock, TX, USA.

Document Type

Article

Abstract

In Alzheimer Disease (AD), non-verbal skills often remain intact for far longer than verbally mediated processes. Four (1 female, 3 males) participants with early-stage Clinically Diagnosed Dementia of the Alzheimer Type (CDDAT) and eight neurotypicals (NTs; 4 females, 4 males) completed the emotional valence determination test (EVDT) while undergoing BOLD functional magnetic resonance imaging (fMRI). We expected CDDAT participants to perform just as well as NTs on the EVDT, and to display increased activity within the bilateral amygdala and right anterior cingulate cortex (r-ACC). We hypothesized that such activity would reflect an increased reliance on these structures to compensate for on-going neuronal loss in frontoparietal regions due to the disease. We used diffusion tensor imaging (DTI) to determine if white matter (WM) damage had occurred in frontoparietal regions as well. CDDAT participants had similar behavioral performance and no differences were observed in brain activity or connectivity patterns within the amygdalae or r-ACC. Decreased fractional anisotropy (FA) values were noted, however, for the bilateral superior longitudinal fasciculi and posterior cingulate cortex (PCC). We interpret these findings to suggest that emotional valence determination and non-verbal skill sets are largely intact at this stage of the disease, but signs foreshadowing future decline were revealed by possible WM deterioration. Understanding how non-verbal skill sets are altered, while remaining largely intact, offers new insights into how non-verbal communication may be more successfully implemented in the care of AD patients and highlights the potential role of DTI as a presymptomatic biomarker.

Publication Date

1-1-2017

Publication Title

Frontiers in aging neuroscience

ISSN

1663-4365

Volume

9

First Page

37

PubMed ID

28298891

Digital Object Identifier (DOI)

10.3389/fnagi.2017.00037

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