δ scores predict multiple neuropsychiatric symptoms

Area of Science:

• Neuropsychology
• Cognitive Science
• Gerontology

Background:

• Dementia severity correlates with general intelligence (g) via a latent dementia phenotype (δ).
• The relationship between behavioral and psychological symptoms of dementia (BPSD) and δ versus domain-specific cognitive impairments remains unclear.

Purpose of the Study:

• To investigate whether a novel measure of dementia severity (dDx), a δ homolog, predicts prospective BPSD.
• To examine the association of dDx with BPSD, controlling for baseline behavior, demographics, biomarkers, and treatments.
• To compare the predictive power of dDx against domain-specific memory (MEM) and executive function (EF) measures for BPSD.

Main Methods:

• Utilized data from 723 Mexican-American and non-Hispanic White participants in the Texas Alzheimer's Research and Care Consortium (TARCC).
• Assessed prospective BPSD using the Neuropsychiatric Inventory (NPI-Q) over one year.
• Employed dDx for categorical dementia diagnosis and derived MEM and EF composite scores as predictors.

Main Results:

• Diagnosed dementia (FSCI via dDx) predicted increased frequency of 11 out of 12 BPSD, independent of covariates.
• Age, depressive symptoms, and executive function (EF) were associated with specific BPSD, while memory (MEM) was not.
• Dementia severity, as indicated by dDx scores, correlated with higher total NPI-Q scores over time.

Conclusions:

• The general dementia phenotype (δ) is non-specifically associated with multiple BPSD.
• Findings suggest a dementia-specific behavioral profile linked to general intelligence deficits, rather than localized pathology.
• dDx serves as a valid predictor of BPSD, highlighting the role of general cognitive impairment in behavioral disturbances in dementia.