A preliminary study of cerebral blood flow, aging and dementia in people with Down syndrome.
S Thalman, K L Van Pelt, A-L Lin and 8 others
PMID 32996650WHAT IT FOUND
In adults with Down syndrome, cerebral blood flow drops significantly after age 45 and is lowest in those diagnosed with Alzheimer's disease.
Lower blood flow correlates with worse cognitive scores, suggesting it may be an early marker for dementia.
Key findings
01Adults with Down syndrome and probable Alzheimer's disease had significantly lower global cerebral blood flow than both controls and those with Down syndrome but no dementia.
02Within the Down syndrome group, lower cerebral blood flow was associated with greater impairment on cognitive tests and informant reports of dementia.
03Cerebral blood flow in people with Down syndrome showed a non-linear decline, with a rapid drop observed after age 45.
STILL TO COME
How it was doneWhat they foundWhat it means for SLPs
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What it does not show
The study was cross-sectional, meaning it measured participants at one point in time. It cannot prove that low blood flow causes dementia or predict individual decline rates. The sample size was small, particularly the group with dementia (7 people). Participants with Down syndrome were younger on average than the control group, which could influence comparisons. The MRI technique used (ASL) is sensitive to blood flow speed, and some of the observed 'low flow' in older participants may have been an imaging artifact (residual arterial signal) rather than true physiological reduction, although researchers attempted to account for this.
Declared interests
No conflicts of interest were declared. The study was supported by the National Institutes of Health (N.I.H., Extramural).
The easy way to misread this
Do not interpret the rapid decline in blood flow after age 45 as a definitive diagnostic marker for individual patients. This is a preliminary group-level finding from a small cross-sectional study, and the observed drop may be partly influenced by imaging artifacts rather than pure physiological change.