Effects of age on the hippocampus and verbal memory in adults with autism spectrum disorder: Longitudinal versus cross-sectional findings.
Broc A Pagni, Melissa J M Walsh, Edward Ofori and 7 others
PMID 36053945WHAT IT FOUND
Over two to three years, autistic adults had smaller average hippocampal volumes and faster decline than neurotypical adults.
In the same group, 33% showed clinically meaningful short-term verbal memory decline, compared with 4% of neurotypical adults.
Key findings
01In 45 adults followed for 2 to 3 years, the autism group had smaller average hippocampal volumes than the neurotypical group and showed faster decline over time.
02In the same follow-up, 33% of autistic adults had a clinically meaningful decline in short-term verbal memory, compared with 4% of neurotypical adults.
03Cross-sectional results did not show the same aging pattern. Short-term verbal memory worsened with age in neurotypical adults, but not in autistic adults.
STILL TO COME
How it was doneWhat they foundWhat it means for SLPs
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What it does not show
The longitudinal findings come from 45 adults, and the authors said the sample was small and mostly middle-aged. Follow-up was only 2 to 3 years, which may be too short to detect group differences in fornix change. There were too few autistic women to examine sex differences in change over time. The sample was restricted to cognitively able adults, excluding people with IQ below 70, dementia, stroke, and some other conditions. Cross-sectional and longitudinal results disagreed, so single-time age comparisons may be affected by cohort effects. The study was not an intervention study, so it cannot show that any treatment changes these outcomes.
Declared interests
The authors report no competing interests. The publication types list U.S. government, non-U.S. government, and NIH extramural research support.
The easy way to misread this
Do not read the 33% decline rate as proof that most autistic adults develop dementia or that verbal memory inevitably worsens with age. The longitudinal group had 45 adults, mostly middle-aged, and the authors called the findings preliminary. Cross-sectional results did not show the same age pattern.