Diffusion tensor imaging biomarkers for assessing cognitive and physical function in aging.

The design is cross-sectional, so it cannot show that white-matter changes cause physical or cognitive decline. It did not account for comorbidities or lifestyle factors that can affect both white-matter integrity and function. Only age, sex and education were used as covariates. Participants had to be community-dwelling, able to walk independently and able to consent, and severe cognitive impairment was excluded, so results do not apply to more severely impaired patients. Some participants were excluded because of neurological disorders or unstable conditions during MRI, which may limit generalisability. The tests and sample were from Korea, using Korean cognitive and language measures, so findings may not transfer directly to other languages or cultural settings. The study did not test whether DTI improves clinical decisions, predicts decline over time or guides therapy.

The funder named is the National Research Foundation of Korea. The supplied text does not include an author conflict-of-interest declaration.

Do not conclude that diffusion MRI can diagnose age-related decline or guide therapy. The study reports associations between white-matter measures and test scores in a cross-sectional cohort, not a clinical test, prediction rule or treatment effect.