Decreased BOLD Signal Variability in Middle-Aged and Older Adults on the Autism Spectrum

Area of Science:

• Neuroscience
• Developmental Psychology
• Gerontology

Background:

• Autism spectrum disorder (ASD) is a lifelong neurodevelopmental condition.
• Brain development in ASD diverges from neurotypical (NT) individuals, but age-related changes in older adults are not well understood.
• Understanding these changes is vital for developing targeted interventions and screenings.

Purpose of the Study:

• To investigate age-related changes in brain function, specifically blood-oxygen-level-dependent (BOLD) signal variability (BSV), in older adults with ASD compared to NT adults.
• To test the hypothesis that adults with ASD exhibit reduced BSV and steeper age-related declines than NT adults.

Main Methods:

• Resting-state functional magnetic resonance imaging (fMRI) was used to assess BSV in 28 adults with ASD and 39 age-matched NT adults (aged 40-70).
• General linear models analyzed diagnostic group, age, and group-by-age interactions, controlling for motion.
• Specific brain regions examined included the right insular, left temporal occipital fusiform, right frontal orbital, and right inferior lateral occipital cortex.

Main Results:

• Significant group-by-age interactions were found in several brain regions.
• BSV demonstrated strong negative associations with age in adults with ASD, but not in NT adults.
• These results indicate that BSV decreases may manifest earlier in adults with ASD.

Conclusions:

• The findings suggest that adults with ASD may experience earlier decreases in BSV compared to their neurotypical counterparts.
• This pattern is consistent with potential accelerated brain aging in ASD.
• Longitudinal studies are required to definitively determine if these differences reflect accelerated aging or persistent lifelong variations in brain function.