Browsing by Author "Willis, Brian"

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    Frontolimbic atrophy is associated with agitation and aggression in mild cognitive impairment and Alzheimer's disease
    (Wiley, 2013) Trzepacz, Paula T.; Yu, Peng; Bhamidipati, Phani K.; Willis, Brian; Forrester, Tammy; Tabas, Linda; Schwarz, Adam J.; Saykin, Andrew J.; Alzheimer's Disease Neuroimaging Initiative; Psychiatry, School of Medicine
    Background: The neuroanatomy of agitation and aggression in Alzheimer's disease is not well understood. Methods: We analyzed 24 months of Alzheimer's Disease Neuroimaging Initiative data for patients with Alzheimer's disease, mild cognitive impairment-stable, and mild cognitive impairment-converter (n = 462) using the Neuropsychiatric Inventory Questionnaire Agitation and Aggression subscale. Magnetic resonance imaging regions of interest that correlated with Neuropsychiatric Inventory Questionnaire Agitation and Aggression subscale raw scores were included in mixed-model, repeated-measures analyses of agitation and aggression over time with age, sex, apolipoprotein E ε4 status, education, and Mini-Mental State Examination score as covariates. Results: Neuropsychiatric Inventory Questionnaire Agitation and Aggression subscale scores worsened in patients with Alzheimer's disease and in mild cognitive impairment-converter (P < .05; trend for mild cognitive impairment, P = .0518). Greater agitation and aggression severity was associated with greater atrophy of frontal, insular, amygdala, cingulate, and hippocampal regions of interest (P < .05). Mini-Mental State Examination score was significant in mixed-effect model repeated measures only in mild cognitive impairment-converters for posterior regions of interest. Demographics and apolipoprotein ε4 were not associated with agitation and aggression. Conclusions: Agitation and aggression in Alzheimer's disease and mild cognitive impairment is associated with neurodegeneration affecting the anterior salience network that may reduce capacity to process and regulate behaviors properly.
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    Subscale Validation of the Neuropsychiatric Inventory Questionnaire (NPI-Q): Comparison of ADNI and NACC Cohorts
    (Elsevier, 2013) Trzepacz, Paula T.; Saykin, Andrew; Yu, Peng; Bhamditipati, Phani; Sun, Jia; Dennehy, Ellen B.; Willis, Brian; Cummings, Jeffrey L.; Alzheimer's Disease Neuroimaging Intiative; Radiology and Imaging Sciences, School of Medicine
    Objective: Neuropsychiatric symptoms are prevalent in mild cognitive impairment (MCI) and Alzheimer disease (AD) and commonly measured using the Neuropsychiatric Inventory (NPI). Based on existing exploratory literature, we report preliminary validation of three NPI Questionnaire (NPI-Q-10) subscales that measure clinically meaningful symptom clusters. Methods: Cross-sectional results for three subscales (NPI-Q-4-Frontal, NPI-Q-4-Agitation/Aggression, NPI-Q-3-Mood) in amnestic MCI and AD dementia cases from the National Alzheimer's Coordinating Center (NACC) and Alzheimer's Disease Neuroimaging Initiative (ADNI) databases were analyzed using confirmatory unrotated principal component analysis. Results: ADNI contributed 103 MCI, 90 MCI converters, and 112 AD dementia cases, whereas NACC contributed 1,042 MCI, 763 MCI converters, and 3,048 AD dementia cases. NACC had higher baseline mean age (75.7 versus 74.6), and more impaired mean scores (at month 24) on Mini-Mental State Exam (19.5 versus 22.4) and NPI-Q-10 (5.0 versus 4.3), and all NPI-Q subscales than ADNI. Medians were not different between cohorts for NPI-Q-4-Agitation/Aggression, and NPI-Q-3-Mood, however. Each item on all scales/subscales contributed variance in principal component analysis Pareto plots. All items in Factor (F) 1 for each scale/subscale projected in a positive direction on biplots (revealing coherence), whereas F2 and F3 items showed more spatial separation (revealing independence). There were remarkable similarities between cohorts for factor loadings and spatial patterns of item projections, although factor item identities varied somewhat, especially beyond F1. Conclusion: The similar pattern of results across two cohorts support validity of these subscales, which are worthy of further psychometric evaluation in MCI and AD patients and preliminary application in clinical settings.