Rethinking Multiple Sclerosis Clinical Course Classifications in the Modern Era: Daniel Ontaneda, MD, PhD

WATCH TIME: 3 minutes

“We now understand MS as a single disease with different biological processes occurring in different proportions over time. Those processes are influenced not only by treatment, but also by comorbidities, lifestyle factors, and what patients themselves report experiencing.”

How clinicians define and classify multiple sclerosis (MS) has continued to evolve over the past decade, driven by advances in imaging, biomarkers, and an improved understanding of disease biology. The 2024 revision of the McDonald Diagnostic criteria further accelerated this shift by expanding how MS can be diagnosed earlier and across a broader range of clinical and radiologic contexts, including individuals with minimal or atypical symptoms.

Radiologic considerations sit at the center of this evolution. Updated diagnostic frameworks increasingly rely on MRI not only to establish dissemination in space and time, but also to identify disease activity that may not be clinically apparent. At the 2026 Americas Committee for Treatment & Research in Multiple Sclerosis (ACTRIMS) Forum, held February 5-7 in San Diego, California, MS expert Daniel Ontaneda, MD, PhD, touched on these concepts in a session titled Rethinking MS Clinical Course Descriptors: Radiological Considerations.

During the meeting, Ontaneda, a staff neuroimmunologist at Cleveland Clinic, sat down to discuss his presentation and the evolution of MS description over time. Throughout the conversation, he explained how focal inflammatory activity and progressive mechanisms coexist to varying degrees across patients and disease stages, challenging the traditional separation between relapsing and progressive MS. Furthermore, Ontaneda, an ACTRIMS attenedee for several years, highlighted the growing role of patient-reported outcomes, comorbidities, and real-world factors in shaping how clinicians understand disease activity, progression, and overall disease burden.

Click here for more 2026 ACTRIMS Forum coverage.