Cognitive, functional decline may occur 10 years before first stroke

Patients who had a stroke had steeper declines in cognitive and daily functioning up to 10 years prior to their first stroke compared with those who never had a stroke.

The findings suggest that “accumulating intracerebral pathology already has a clinical impact before stroke,” researchers noted in a descriptive study published in the Journal of Neurology, Neurosurgery & Psychiatry.

“Understanding this prestroke deterioration could help to unravel the pathophysiology of stroke and to identify those at high risk [for] stroke for inclusion in primary prevention trials or targeted therapy,” Alis Heshmatollah, MD, of the department of epidemiology at Erasmus MC University Medical Center in the Netherlands, and colleagues wrote. “A few studies have indeed demonstrated a decline in cognition and daily functioning [4 to 6] years before stroke. However, several knowledge gaps remain unaddressed.”

These gaps included a limited number of cognitive tests having been previously studied, as well as a limited number of studies that describe the complete trajectory of cognition and daily functioning both before and after a stroke.

To address these research gaps, the investigators repeatedly evaluated cognition among 14,712 patients between 1990 and 2016 using a battery of tests, including the Mini-Mental State Examination (MMSE), the 15-Word Learning Test, the Letter-Digit Substitution Task, the Stroop Task, the Verbal Fluency Test, and the Purdue Pegboard, as well as basic and instrumental activities of daily living. Participants had taken part in the Rotterdam Study, a large prospective population-based cohort study in the Netherlands designed to identify causes and consequences of diseases in the general population. Heshmatollah and colleagues assessed incident stroke by continuously monitoring medical records until 2018 and matched participants who had incident stroke in a 1:3 ratio with participants who did not according to sex and birth year. They used adjusted linear mixed effects models to construct trajectories of cognition and daily functioning 10 years before and 10 years after stroke among individuals who had one, as well as corresponding trajectories of individuals who did not have a stroke.

Results showed first-ever stroke among 1,662 participants during a mean follow-up of 12.5±6.8 years. Those who had a stroke exhibited deviation in cognition and daily functioning compared with those without a stroke up to 10 years before stroke diagnosis. The researchers observed significant deviations before stroke in scores from the MMSE (6.4 years), the Stroop Task (5.7 years), the Purdue Pegboard (3.8 years) and basic activities of daily living and instrumental activities of daily living (2.2 and 3 years, respectively).

“Women, APOE e4 carriers and individuals with lower educational level were particularly vulnerable to these declines,” Heshmatollah and colleagues wrote. “Our findings suggest that accumulating intracerebral pathology before the acute event already has a clinical impact, allowing for the identification of high-risk individuals.”