Background: Alzheimer’s Disease (AD) can develop for decades before clinical symptoms appear, and early detection will probably be important for effective treatment in the future. Accessible and accurate cognitive assessment of predementia AD is needed.
Objectives: This thesis investigates neuropsychological methods for early identification of AD using longitudinal data from a brief neuropsychological battery. In Paper I, the accuracy and predictive value of different mild cognitive impairment (MCI) criteria applied in the brief battery is evaluated over a two-year period. Paper II presents two-year regression-based change norms for the brief screening battery and examines cognitive change in clinical and AD biomarker groups. Paper III assesses whether cognitive change scores presented in Paper II are associated with biomarker pathology in cognitively unimpaired older adults.
Methods: Participants were from the Dementia Disease Initiation (DDI) study. Normative samples also included participants from the Gothenburg MCI and Trønderbrain cohorts. The brief neuropsychological battery comprised six measures and was administered at baseline and two-year follow-up assessments. Neuropsychological associations with cerebrospinal fluid biomarkers were investigated in all papers. Paper III also included blood biomarkers.
Results and conclusions: In paper I, using a brief battery for MCI characterization was found to have modest utility to predict AD diagnosis, and low utility for predicting biomarker pathology. In paper II, we developed regression-based change norms for Scandinavian adults ages 41 to 84 and found that the change scores identified cognitive decline in MCI and biomarker positive symptomatic participants. Paper III indicated that change scores were not useful in detection of subtle cognitive decline associated with biomarker pathology in cognitively unimpaired individuals.