A blood test measuring the protein p-tau217 can predict cognitive decline in cognitively healthy older adults with accuracy exceeding 90%, according to a study published in the Journal of the American Medical Association. Researchers at Mass General Brigham and Harvard Medical School followed 2,684 adults over several years and found that rising levels of the biomarker in blood samples signalled the accumulation of tau pathology in the brain long before clinical symptoms appeared. The test matched or surpassed the diagnostic performance of PET scans and lumbar punctures, the current gold standards, opening the possibility of routine, low-cost screening for Alzheimer’s disease in its preclinical stage.

A separate line of attack is emerging from immunotherapy. A phase 1b trial led by the Weizmann Institute of Science in Israel, published in Nature Medicine, tested an anti-PD-L1 antibody called IBC-Ab002 in 40 patients with early-stage Alzheimer’s across eleven centres in the United Kingdom, Israel and the Netherlands. Rather than targeting amyloid plaques directly, the drug aims to restore age-related immune dysfunction that fuels brain inflammation. The trial was designed to assess safety and tolerability; efficacy endpoints will require larger studies.

Observational research is also refining the understanding of how everyday behaviours may influence brain ageing. Japanese scientists analysing data from nearly 1,900 British adults over 50 found that regular attendance at museums, galleries, theatres or cinemas was associated with a physiological age roughly three years younger, as measured by markers including blood pressure, BMI and walking speed. The effect size was comparable to that of frequent physical activity, though the study, published in the Journal of Epidemiology and Community Health, cannot establish causation. Separately, preliminary findings presented at a recent scientific conference linked speaking two languages to a six-year delay in brain ageing, and four languages to a delay of up to thirteen years. However, a meta-analysis of multiple studies found that multilingualism does not lower the incidence of dementia but delays diagnosis by two to five years, likely by building cognitive reserve that masks early symptoms. Researchers caution that education, socioeconomic status and migration background confound the picture: migrants often face a higher dementia risk despite speaking multiple languages, while a study of American women linked anxiety about ageing to accelerated epigenetic ageing.

Viewed from Tehran, Iranian neurologists emphasise that modifiable risk factors—including metabolic health, physical activity, mental stimulation and oral hygiene—remain the most actionable levers for individuals. The blood test now moves towards validation in broader clinical settings, while the immunotherapy programme is expected to advance to larger efficacy trials. Regulatory assessments of the p-tau217 assay for population-level screening will be the next milestone to watch.