Neuropsychiatric symptom trajectories and their associations with cognitive impairment and white matter microstructure of the cerebellar peduncles in Alzheimer’s disease

INTRODUCTION: Alzheimer’s disease (AD) is often accompanied by neuropsychiatric symptoms (NPS) such as apathy or aggression. The present study uses longitudinal data from the Alzheimer’s Disease Neuroimaging Initiative (ADNI) to characterize different NPS trajectories, their association with cognitive impairment, and white matter microstructure of the cerebellar peduncles as a possible biomarker of NPS progression. METHODS: We assessed the association of different trajectories of NPS identified though growth mixture models with cognitive decline and white matter microstructure changes over the course of two years. RESULTS: Four classes of NPS trajectories were identified in 785 individuals. These classes predicted cognitive decline over time but were unrelated to changes in the microstructure of the cerebellar peduncles in a subsample of 60 individuals for whom sufficient longitudinal neuroimaging data was available. DISCUSSION: There are substantial individual differences in NPS trajectories. Distinguishing classes of NPS trajectories is important to predict cognitive decline.