Background: Hypertension may result in cognitive decline. It is still not well established that treating the hypertension reduces the cognitive decline or not. Therefore the present study was planned to assess the effect of hypertension on cognitive functions by event related potential (ERP) P300 and effect of antihypertensive therapy on cognitive functions if any.

Material and Methods: The study compared the cognitive functions using ERP P300 among three groups comprised of 30 newly diagnosed hypertensives, 30 hypertensives undergoing treatment and matched controls.

Result: Newly diagnosed hypertensive had increased P300 latency and decreased P300 amplitude indicating their cognitive impairment. P300 latency was significantly less in patients on treatment than newly diagnosed hypertensives signifying that cognition improved with treatment. But still there was significant difference between patients taking treatment and controls in relation to P300 parameters which implied that even after treatment cognitive functions did not return up to normal level.

Conclusion: There is definite decline in cognition amongst untreated hypertensive subjects which could be detected with ERP P300 test. Antihypertensive treatment can reduce or slows down cognitive decline as well as improve the cognitive dysfunction in hypertensive patients.