JAMA Publication: Trajectory of Cognitive Decline After Incident Stroke

Each year, 795 000 US residents experience a stroke.¹ In 2010, almost 7 million adults were stroke survivors.¹ Over the last 2 decades, age-standardized years lived with disability rates increased by 40% for stroke—the only major disease to show a significant increase in this important disability measure.² Disability due to stroke is a major driver of health burden and costs for families, health care systems, and public programs such as Medicare and Medicaid.² Cognitive impairment after stroke is a major contributor to this disability,^3,4 and its prevalence has increased sharply in older adults.^5,6 Despite its enormous social and economic burden, poststroke cognitive impairment has been called a “neglected consequence of stroke.”⁷

Although stroke is associated with acute cognitive decline,³ it is unclear whether stroke survivors acquire a faster rate of cognitive decline over the years following the event (ie, slope) compared with the prestroke rate of cognitive decline, after accounting for the acute cognitive decline at the time of the event.⁸ While cognitive decline over the years before stroke is common⁹ and is associated with poststroke cognitive decline,¹⁰ most studies of stroke cannot measure actual changes in the rate of cognitive decline associated with stroke because they lack measures of patients’ prestroke cognitive changes or use proxy-reported measures.^10–14 Moreover, most studies of stroke have not measured both the acute decline in cognitive function at the time of the stroke and the change in the rate of cognitive decline over the years after stroke simultaneously.¹⁵ One study⁹ suggests that stroke causes an acute decline in cognitive function at the time of the event but does not cause faster cognitive decline over the years following the event.

We hypothesized that stroke causes an acute decline in cognitive function at the time of the event and also faster cognitive decline during the years following the event.