The study, which was published on the medical website BMJ, examined 5,000 seniors.
Researchers checked their blood pressure every three months and tested their reaction time and memory.
The study found that people with blood pressure that varied from visit to visit performed worse on the tests than those with stable readings.
Because the study shows only an association --and not a cause-and-effect relationship -- researchers caution it is too early to make definitive claims about blood pressure inconsistency and mental decline.
