by Justin Jackson , Medical Xpress

Credit: Pixabay/CC0 Public Domain

A University of Alabama at Birmingham Heersink School of Medicine-led study suggests that first-time transient ischemic attacks (TIA) are associated with long-term cognitive decline.

Findings indicate that individuals who experienced a TIA had an annual cognitive decline similar to those who had a stroke, despite the transient nature of the event and the absence of visible brain lesions on diffusion-weighted imaging.

TIA is an acute ischemic event in the brain that typically resolves within two to 15 minutes, often leaving no detectable structural damage on imaging. While stroke is well recognized as a major risk factor for cognitive impairment, the impact of TIA on long-term cognitive function has been less understood.

Prior research has shown that individuals with TIA are at a higher risk of developing dementia over five years, but whether this decline is directly caused by the TIA or due to preexisting conditions remained unclear.

In the study, “Cognitive Decline After First-Time Transient Ischemic Attack,” published in JAMA Neurology, researchers analyzed data from the Reasons for Geographic and Racial Differences in Stroke (REGARDS) study, a population-based cohort tracking over 30,000 Black and White participants for cerebrovascular events.

Researchers compared cognitive trajectories of individuals with first-time TIA, first-time stroke, and asymptomatic community controls. All cerebrovascular events were confirmed through neuroimaging and adjudicated by stroke specialists.

Verbal fluency and memory were assessed biannually using standardized cognitive tests. The primary outcome was a composite cognitive score derived from four tests measuring memory and verbal function. Adjusted segmented regression models were used to compare the groups’ pre-event and post-event cognitive trajectories.

The cohort included 356 individuals with first-time TIA (mean age, 66.6 years), 965 individuals with first-time stroke (mean age, 66.8 years), and 14,882 asymptomatic controls (mean age, 63.2 years).

Data showed that before any stroke or TIA occurred, participants in the stroke group already had lower cognitive test scores compared to both the TIA group and the control group. This could mean that underlying vascular issues (like poor blood flow or silent mini-strokes) were already affecting cognition before they had a major stroke. After a stroke, patients showed a clear, immediate cognitive drop followed by a gradual decline.

TIA patients did not show an immediate cognitive drop directly after their event. They did experience accelerated cognitive decline at an annual decline rate comparable to the stroke group and significantly greater than the control group. Cognitive decline in the TIA group was primarily driven by memory impairments rather than verbal fluency.

Findings suggest that TIA, despite its transient symptoms and lack of detectable brain injury by imaging, can still have long-term consequences on cognitive health. Possible mechanisms include subtle ischemic injury, neuroinflammation, blood-brain barrier dysfunction, or interactions with underlying neurodegenerative factors.

Further research is needed to determine whether TIA contributes to dementia risk and to develop targeted post-TIA interventions to mitigate cognitive decline.

More information: Victor A. Del Bene et al, Cognitive Decline After First-Time Transient Ischemic Attack, JAMA Neurology (2025). DOI: 10.1001/jamaneurol.2024.5082

Journal information:Archives of Neurology

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