Dr. Ronald Postuma,
Assistant Professor, McGill University Research Institute
Funded by Quebec Research Fund on Parkinson
Pilot Project Grant: $40,620
Funded by Quebec Research Fund on Parkinson

Association of Cognitive dysfunction with Orthostatic Hypotension in patients with Parkinson’s disease

Dr. Ronald Postuma, a neurologist and assistant professor at McGill University, was conducting a long-term study involving people with Parkinson’s disease when he discovered a phenomenon other researchers had seldom observed.

People with Parkinson’s, who had dementia or mild cognitive impairment that was affecting their judgment, reasoning and/or memory also suffered from low blood pressure that dropped rapidly whenever they stood up. Postuma began to wonder if the two things were connected.

“Maybe it’s bad for your brain to have your blood pressure drop 20 times a day every time you stand up,” he muses.

He also observed that the cognitive impairment is not consistent in many of his patients with Parkinson’s with dementia.

“People are great, and then they’re awful, they’re great, and then they’re awful. One wonders if there is a connection between these fluctuations in blood pressure and dementia.”

Finally, Postuma documented that his Parkinson’s patients with drops in blood pressure on standing were also at increased risk of developing dementia within five years, if they didn’t already have it when he noted their blood pressure fluctuations.

“The good news about blood pressure drops is that they are at least partially fixable,” says Postuma.

Postuma and his colleagues are now exploring the connection between the blood pressure drops and episodes of dementia or cognitive impairment. Working with about 30 people with Parkinson’s, they will track their blood pressure, both at home and in Postuma’s clinic, assess their current medications, and treat the low blood pressure with medication for the condition, which is called orthostatic hypotension. The researchers will also administer cognitive tests when the participants are lying down and standing up, to track potential changes in their alertness and attention when their blood pressure is normal and when it has fallen sharply.

Ideally, Postuma hopes to demonstrate that blood pressure is connected to cognition, and that when treated, people’s reasoning, judgment and memory improve. If he can prove the connection, then doctors need to screen their patients to look for problems with low blood pressure, Postuma stresses.

His research could provide an important and relatively easy solution to improve the debilitating effects of mild cognitive impairment and dementia that many people with Parkinson’s disease eventually develop.