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

Cross-sectional scans of people scanned once. The authors say the results cannot distinguish accelerated ageing from differences that have been present since childhood, and that longitudinal follow-up is needed. Small sample: 28 autistic and 39 neurotypical adults. The authors call this an inherent problem in this field, and after correcting for multiple comparisons most regions dropped out. The text reports 28 autistic participants while the demographics table lists 29, so the exact group size is unclear. Health status information was missing for 12 neurotypical and 9 autistic participants, so the authors could not rule out that conditions such as high blood pressure partly explain the results. More autistic participants were taking psychotropic medication (9 versus 1); the authors argue this would work against their finding, but it is still a difference between the groups. The main age effect appeared only in the autistic group, which conflicts with earlier reports of age-related decline in neurotypical adults. The authors attribute this to their sample being younger on average (mean 52 years). The link to GABA is presented as a possible mechanism borrowed from other researchers' work, not something measured in this study.

Funded by the National Institute of Mental Health (R01-MH103494) and the National Institute on Minority Health and Health Disparities (S21MD010690, U54MD012397). The authors declare no conflicts of interest. Participants were compensated for their time.

Do not read lower brain signal variability as a thinking or memory problem in autistic adults. This study measured only the blood-oxygen signal during rest, reported no cognitive or behavioural outcomes, and the authors say the results cannot tell us whether older autistic adults are ageing faster or simply differ from neurotypical people in the same way they always have.