Stroke survivors have a faster rate of cognitive decline compared with the norm – and decline is persistent over the next six years, researchers have found.

Researchers from the USA’s University of Michigan Medical School, Ann Arbor, arrived at this finding after examining changes in cognitive function in more than 23 000 individuals who were aged 45 or older.

Every year, millions of people experience a stroke. For survivors, cognitive decline – including memory and thinking speed – is a major cause of disability. Many patients experience these declines immediately after a stroke. The new study examined whether cognitive decline continues several years after.

All participants in the study were free of cognitive impairment at the start of the study. Memory and other measures of cognitive function were recorded at the beginning and at regular intervals throughout a six-year follow-up period. During the study, 515 participants experienced a stroke; the rest remained stroke-free.

Results found that survivors had a faster rate of cognitive decline after stroke compared with the pre-stroke rate. Stroke was associated with an early decline in cognitive function and also accelerated and persistent cognitive decline over the next six years.