The Relationship Between Age, Brain Structure, and Cognition in Chronic Traumatic Brain Injury.
Amber Ayton, Jennie Ponsford, Amelia J Hicks and 3 others
PMID 42140612WHAT IT FOUND
In chronic moderate-severe TBI, middle-aged adults had lower fornix and thalamus brain structure than same-age controls.
In the oldest groups, TBI and control differences were smaller or absent. Lower structure was linked to poorer verbal memory and processing speed.
Key findings
01Compared with non-TBI controls, the TBI group had reduced integrity in all 72 white matter tracts, reduced volume in 12 of 14 subcortical structures, and reduced thickness in 13 of 117 cortical regions.
02In the left thalamus and the left and right fornix, individuals with TBI had lower volume or integrity than same-aged controls in middle age, but not in the oldest groups.
03Lower left and right fornix integrity was associated with poorer processing speed, verbal story memory, and verbal wordlist memory in the TBI group.
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, so it cannot show how an individual person's brain structure changes over time. Older adults in the sample had shorter time since injury than younger participants, which may reflect survival and recruitment biases. Controls had higher premorbid IQ and educational attainment than the TBI group. The oldest age groups were small, and the age-by-group interaction in the fornix and thalamus was not significant after correction in the sensitivity analysis. The sample was limited to adults aged 40 years and above, so it does not address younger adults with chronic TBI. The paper reports MRI and cognitive outcomes, not physical function outcomes.
Declared interests
The study was supported by the National Health and Medical Research Council under Grant APP 1127007. The authors declared no potential conflicts of interest.
The easy way to misread this
Do not conclude that older adults with chronic TBI have accelerated brain ageing. The study did not find a steeper age-related decline in older adults with TBI; differences in the left thalamus were absent in the 70s and 80s, and differences in the fornix were absent in the 80s.