Mini-strokes may cause long-term memory decline

A new study led by researchers at the University of Alabama at Birmingham suggests that even a brief, temporary disruption in blood flow to the brain—known as a transient ischemic attack (TIA)—can lead to long-term cognitive decline.

These findings challenge the assumption that TIA has no lasting effects simply because symptoms disappear quickly and brain scans do not show visible damage.

What is a TIA?

A transient ischemic attack, often called a “mini-stroke,” happens when blood flow to the brain is temporarily blocked. Unlike a full stroke, where brain damage is usually visible on scans, TIA symptoms—such as difficulty speaking, weakness, or dizziness—usually last only a few minutes before disappearing.

This has led many to believe that TIAs are harmless. However, this new research suggests that they can have hidden, long-term effects on memory and thinking skills.

The Study and Its Findings

The study, published in JAMA Neurology, analyzed data from a long-term health project called the REGARDS study, which tracks over 30,000 Black and White adults across the U.S. Researchers compared three groups of people:

1. 356 individuals who had their first TIA (average age: 66.6 years)
2. 965 individuals who had their first stroke (average age: 66.8 years)
3. 14,882 individuals with no history of stroke or TIA (average age: 63.2 years)

To measure cognitive abilities, participants took standardized memory and language tests every two years. The researchers then compared how their cognitive abilities changed over time.

Key Results

• Before experiencing a stroke or TIA, those in the stroke group already performed worse on cognitive tests than those in the TIA or control groups. This suggests that hidden vascular problems may have been affecting their brain function before their major stroke.
• After having a stroke, patients experienced an immediate and noticeable drop in cognitive function, followed by continued decline over time.
• Those who had a TIA did not show an immediate drop in cognitive function, but their memory declined at the same rate as stroke patients in the years that followed.
• The control group, who never had a TIA or stroke, had much slower cognitive decline compared to both the stroke and TIA groups.
• The decline in TIA patients was mainly due to worsening memory rather than problems with verbal fluency (such as difficulty finding words).

Why Does a “Mini-Stroke” Cause Cognitive Decline?

Even though TIA symptoms go away quickly, researchers believe they might still cause small, hidden injuries to the brain. These injuries may not be visible on standard brain scans but could trigger processes that harm cognitive function over time. Possible explanations include:

• Subtle brain damage: Tiny ischemic injuries that do not show up on imaging but still affect memory and thinking.
• Inflammation: The body’s response to a TIA might lead to chronic inflammation that damages brain cells.
• Blood-brain barrier dysfunction: A TIA could weaken the protective barrier around the brain, allowing harmful substances to enter and cause long-term damage.
• Interaction with other conditions: TIA may speed up cognitive decline in people already at risk for neurodegenerative diseases like Alzheimer’s.

What This Means for People Who Have Had a TIA

This study highlights the need for greater awareness of TIA as a serious event that can have lasting effects. While stroke is already recognized as a major risk factor for dementia, TIA has often been overlooked.

These findings suggest that people who experience a TIA should be closely monitored for cognitive changes and may benefit from early interventions to protect their brain health.

Next Steps in Research

Scientists still need to figure out whether TIA directly increases the risk of dementia and what can be done to slow cognitive decline in TIA patients. Future studies may explore treatments such as:

• Lifestyle changes (exercise, diet, and brain-stimulating activities)
• Medications to improve blood flow and reduce inflammation
• Early cognitive rehabilitation programs

This study provides strong evidence that even brief interruptions in blood flow to the brain should not be ignored. If you or someone you know has had a TIA, it is important to talk to a doctor about long-term brain health and ways to reduce the risk of further decline.

The research findings can be found in JAMA Neurology.

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