Stroke survivors at increased risk of developing dementia do not have therapies to reduce that risk, but new Monash University-led research could help change that.
Published in JAMA Network Open, the study found aerobic exercise after an ischemic stroke is safe and may help cognition but did not preserve brain volume more than a balance and stretching intervention. However, any exercise was better than none for protecting against brain shrinkage.
The study, which also involved institutions including the University of Melbourne, Epworth HealthCare, The Florey, Austin Health, Eastern Health, and Western Health, was presented recently at the European Stroke Organisation Conference.
The clinical trial involved 104 ischemic stroke survivors who were randomised to complete either an eight-week cardiorespiratory (aerobic) exercise program or a balance and stretching program commencing two months after their stroke.
The study was initially completed in hospital gyms, but pandemic changes meant that most exercised in their own homes, joining a telehealth session with their exercise professional three times per week.
Conducted at four metropolitan healthcare services in Melbourne, participants returned for study visits for brain imaging, cognitive, mood and fitness testing, and completed dietary surveys.
They were fitted with 24-hour blood pressure monitoring, and gave blood and stool samples to investigate effects on blood sugar, inflammation, markers of brain degeneration, and their microbiome (bacterial make-up of the intestine).
One hundred participants completed assessments at four months and 97 people at 12 months. The median age was 67 years, with more men volunteering than women (64 per cent). There were no serious intervention-related adverse events.
Researchers found the aerobic exercise program was safe but did not preserve the size of the hippocampus – a brain structure crucial for memory and spatial navigation – more than a balance and stretching control.
However, there was promising evidence for cognitive preservation. Executive and global cognitive performance at 12-months post-stroke was better in the aerobic group.
First author Professor Amy Brodtmann, who leads the Department of Neuroscience's Cognitive Health Initiative in Monash University's School of Translational Medicine, said that this study addressed a growing unmet need for stroke survivors who wanted to stop their brain from shrinking after stroke, and avoid dementia.
Professor Brodtmann said exercise programs were offered after major cardiac events (cardiac rehabilitation), many cancers, and lung disease, but exercise prescriptions for stroke survivors were lacking.
"Both the cardiorespiratory and balance and stretching control groups lost less brain volume than has been observed in prior studies where no intervention was offered," she said. "Indeed, their brain volume change was comparable to that seen in stroke-free healthy control participants, suggesting that both interventions may protect the brain.
"Our very close testing of our participants will allow us to unpack these effects in subsequent papers. I'm encouraged by the fact that the interventions both seemed to preserve brain volume and cognition."
This study was supported by NHMRC Boosting Dementia Research grant, Rapid Accelerated Research Translation grant, and Heart Foundation Fellowships for Professor Brodtmann.
