Cognitive decline in Dutch‐type hereditary and sporadic cerebral amyloid angiopathy: a 5‐year follow‐up study

INTRODUCTION Cerebral amyloid angiopathy (CAA) is associated with cognitive impairment, but its longitudinal course of cognitive decline remains unclear. We investigated domain‐specific cognitive trajectories in Dutch‐type hereditary (D‐CAA) and sporadic CAA (sCAA) to compare patterns and rates of decline. METHODS We included 181 participants – 93 D‐CAA mutation carriers (59 without, 34 with prior intracerebral hemorrhage [ICH]) and 88 with sCAA (57 without, 31 with ICH) – who underwent annual neuropsychological assessment. Longitudinal change in global cognition, memory, processing speed, and executive function was analyzed using linear mixed models. RESULTS Over 5 years, cognitive decline was subtle but measurable. Memory and processing speed declined in D‐CAA with prior ICH, whereas D‐CAA without ICH and sCAA remained relatively stable. Global cognition showed a modest but significant decline, while executive function remained stable. DISCUSSION CAA‐related cognitive decline appears domain‐ and stage‐dependent, suggesting progressive small‐vessel injury rather than acute hemorrhage may drive deterioration.