The 2024 revision of the McDonald criteria for diagnosis of multiple sclerosis marks a substantial departure from previous iterations, establishing a unified framework that integrates presentation, lesion topography and a flexible combination of paraclinical tools. This Clinical Outlook considers the major changes and their clinical implementation, and the implications of the new criteria.

Approximately half of the people currently with multiple sclerosis (MS) are ≥50 years of age, yet guidelines for management of MS in older age are lacking. This Consensus statement presents the outcomes of an International Advisory Committee on Clinical Trials (IACCT) in MS workshop on ageing and MS, including recommendations for advancing research, care and awareness.

Anti-amyloid treatments for early symptomatic Alzheimer disease have greatly increased the need for biomarker confirmation of amyloid pathology and blood biomarker tests offer an accessible and scalable biomarker test. This Consensus Statement provides recommendations for the minimum acceptable performance of blood biomarker tests for clinical use.

Autologous haematopoietic stem cell transplantation (AHSCT) is a treatment option for some forms of multiple sclerosis (MS), but uncertainties remain about its implementation in clinical practice and treatment protocols need to be optimized. This Consensus Statement provides guidance and recommendations for the use of AHSCT in MS and neuromyelitis optica spectrum disorders.

A new study presented at the 2025 American Neurological Association Annual Meeting indicates that area postrema syndrome in people with neuromyelitis optica spectrum disorder is related to elevated levels of the gut hormone glucagon-like peptide 1 and its receptor GLP-1R.

A new meta-analysis presented at the 2025 American Neurological Association Annual Meeting shows that initiation of hormone replacement therapy in women soon after the onset of menopause is associated with a reduced risk of Alzheimer disease.

In the 2024 revisions of the McDonald criteria for diagnosis of multiple sclerosis (MS), dissemination in time is no longer required. This paradigm shift is the result of advances in understanding of MS and the development of other biomarkers, enabling earlier diagnosis and treatment that will ultimately improve long-term outcomes.

The 2024 revisions of the McDonald criteria for multiple sclerosis for the first time permit diagnosis in asymptomatic people with MRI findings suggestive of multiple sclerosis pathology. Although these changes promise opportunities for earlier treatment and improved clinical outcomes, they present a new risk in the form of overdiagnosis.

The 2024 revision of the McDonald criteria for diagnosis of multiple sclerosis marks a substantial departure from previous iterations, establishing a unified framework that integrates presentation, lesion topography and a flexible combination of paraclinical tools. This Clinical Outlook considers the major changes and their clinical implementation, and the implications of the new criteria.

Updates to the McDonald criteria for diagnosis of multiple sclerosis emphasize the value placed on recognizing the earliest manifestations of multiple sclerosis, providing new opportunity to advance understanding of the prodromal phase.