ALZHEIMER'S DISEASE: ADVANCES IN EARLY DIAGNOSIS, BIOMARKERS, AND THERAPEUTIC PERSPECTIVES

Alzheimer's disease is the leading cause of dementia and has a long biological phase preceding advanced functional impairment. The recognition of alterations in beta-amyloid and tau, together with the development of cerebrospinal fluid, neuroimaging, and blood biomarkers, has changed the diagnostic paradigm, enabling the identification of pathophysiology at earlier stages. This review discusses advances in early diagnosis, biomarkers, and therapeutic perspectives, with an emphasis on clinical assessment, cognitive tests, magnetic resonance imaging, amyloid and tau PET, cerebrospinal fluid, plasma beta-amyloid, phosphorylated tau, neurofilament light chain, and glial fibrillary acidic protein. Symptomatic and disease-modifying therapies are also analyzed, including anti-amyloid monoclonal antibodies, their benefits, limitations, the need for confirmation of amyloid pathology, and the risk of amyloid-related imaging abnormalities. Blood biomarkers, especially p-tau217 in high-performance assays, are approaching specialized clinical application, although they do not replace comprehensive clinical assessment. It is concluded that the field is moving toward earlier biological diagnosis and individualized treatment, but access, safety, test interpretation, and long-term clinical benefit remain challenges.