Identifying and characterizing patterns of functional decline in memory clinic patients

Abstract

AbstractBackgroundAlzheimer’s disease and related disorders (ADRD) are characterized by progressive cognitive and functional decline. To improve prognosis, it is important to predict the expected rate of functional decline. In the current study, we sought to uncover patterns of changes in everyday functioning among memory clinic patients, and to explore factors associated with said groups.MethodMemory clinic patients (N=573, 64.7±7.9 years old, 39% female) underwent extensive dementia screening at baseline, and were followed over time (median 1.0 years, range 0.3–6.2 years, N observations=1632). Diagnoses included subjective cognitive decline, mild cognitive impairment, and dementia with varying etiologies. We measured everyday functioning with the Amsterdam Instrumental Activities of Daily Living Questionnaire (A‐IADL‐Q). Longitudinal latent class analysis (LLCA) was used to identify groups of patients based on their rate of change in IADL, including non‐linear trajectories. We subsequently used random forests to explore the associations between the LLCA groups and demographics, neuropsychological test performance, and magnetic resonance imaging rating scales for medial temporal and global atrophy.ResultWe identified six groups: two stable (high and average), three declining (slow, moderate, and fast), and one improving group (see Table 1, Figure 1). All groups differed in baseline A‐IADL‐Q scores, with the declining groups having lower scores. The fast declining group consisted mostly of dementia patients, whereas the high stable group consisted mostly of patients with subjective cognitive decline. The area under the curve of the random forest classification was .95, thus accurately assigning patients to the correct group based on baseline characteristics. The following variables contributed most to the classification of the groups: baseline A‐IADL‐Q score (mean decrease accuracy [MDA]=200.5), a visuospatial task (copy of Rey Complex Figure, MDA=36.6) and a processing speed task (Letter Digit Substitution Task, MDA=18.5). Atrophy rating scales contributed less.ConclusionDifferent trajectories of functional decline were distinguished, and associated with baseline levels of cognitive and daily functioning. Our findings suggest that neuropsychological assessment may provide additional information on future changes in daily functioning. These findings may contribute to a more accurate prognosis of future functional decline, and by extension, future care needs.