Dr. Bradley MacIntosh, Scientist
Brain Sciences Research Program, 
U of Toronto (Sunnybrook Research Institute)
Porridge for Parkinson’s (Toronto) Pilot Project in Honour of Delphine Martin: 1 year $45,000

Biomarkers of cognitive impairment in PD using orthostatic hypotension, white matter & grey matter fMRI metrics: a PPMI study

Even before people with Parkinson’s disease experience motor symptoms that include stiffness or tremors, they may have problems with their blood pressure and cognitive issues that affect their judgment and reasoning ability.

At Toronto’s Sunnybrook Research Institute, Bradley MacIntosh, a neuroimaging scientist, is using imaging technology to try to identify people with these early symptoms of Parkinson’s. MacIntosh is using functional Magnetic Resonance Imaging (fMRI) to scan the brains of people who have difficulty regulating their blood pressure, a problem called orthostatic hypotension.

These blood pressure problems can cause light-headedness, dizziness and fainting, particularly when people stand up. The scans MacIntosh is conducting will track how often the brain is pulsating – a measure of blood flow to the brain. He believes the volatility of that blood flow is bad for the brain, and may be either depriving brain cells of oxygen or flooding them with too much oxygen, at different times. That “pulsatility,” is an indication of the orthostatic hypotension.

MacIntosh hopes to correlate rates of pulsatility with fluctuations in white matter in the brains of people who have already been diagnosed clinically as being in the early stages of Parkinson’s disease. He and his team will also test their cognitive functioning to see if that is also declining. If he can confirm an association with the volatility of blood flow to the brain, and show cognitive decline, he will not only have developed a way to help diagnose Parkinson’s disease, he may also open up treatment avenues. Treating the volatile blood pressure early might prove beneficial.

“What we’re aiming for right now is a non-invasive diagnostic tool using information that is already out there,’’ says MacIntosh. “It’s just a matter of finding and proving that this can be helpful.”

Parkinson’s disease is just one of the many complicated subjects that MacIntosh studies, from physics to jazz. “My life is not complicated, but I like complicated things,” he says. He particularly enjoys working in Parkinson’s research because “there’s a lot of optimism in the field of Parkinson’s.”