title: White Matter Deterioration May Foreshadow Impairment of Emotional Valence Determination in Early-Stage Dementia of the Alzheimer Type.
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.
authors.affiliation: Department of Pharmacology and Neuroscience, Texas Tech University Health Sciences Center Lubbock, TX, USA.
authors.forename: Ravi
authors.initials: R
authors.lastname: Rajmohan
authors.affiliation: Department of Electrical and Computer Engineering, Texas Tech University Lubbock, TX, USA.
authors.forename: Ronald C
authors.initials: RC
authors.lastname: Anderson
authors.affiliation: Department of Human Development and Family Studies, Texas Tech University Lubbock, TX, USA.
authors.forename: Dan
authors.initials: D
authors.lastname: Fang
authors.affiliation: School of Medicine, Texas Tech University Health Sciences Center Lubbock, TX, USA.
authors.forename: Austin G
authors.initials: AG
authors.lastname: Meyer
authors.affiliation: Department of Neurology, Texas Tech University Health Sciences Center Lubbock, TX, USA.
authors.forename: Pavis
authors.initials: P
authors.lastname: Laengvejkal
authors.affiliation: Department of Neurology, Texas Tech University Health Sciences Center Lubbock, TX, USA.
authors.forename: Parunyou
authors.initials: P
authors.lastname: Julayanont
authors.affiliation: Department of Public Health, Texas Tech University Health Sciences Center Lubbock, TX, USA.
authors.forename: Greg
authors.initials: G
authors.lastname: Hannabas
authors.affiliation: Department of Family Medicine, Texas Tech University Health Sciences Center Lubbock, TX, USA.
authors.forename: Kitten
authors.initials: K
authors.lastname: Linton
authors.affiliation: Department of Family Medicine, Texas Tech University Health Sciences Center Lubbock, TX, USA.
authors.forename: John
authors.initials: J
authors.lastname: Culberson
authors.affiliation: Department of Public Health, Texas Tech University Health Sciences Center Lubbock, TX, USA.
authors.forename: Hafiz M R
authors.initials: HM
authors.lastname: Khan
authors.affiliation: Department of Neurology, Texas Tech University Health Sciences Center Lubbock, TX, USA.
authors.forename: John
authors.initials: J
authors.lastname: De Toledo
authors.affiliation: 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.
authors.forename: P Hemachandra
authors.initials: PH
authors.lastname: Reddy
authors.affiliation: 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.
authors.forename: Michael
authors.initials: M
authors.lastname: O'Boyle
keywords: Alzheimer; DTI; brain networks; chimeric faces; emotional valence; fMRI