The following is a summary of “Association of Specific “Critical” Demyelinating Lesions and Motor Impairment in Progressive Multiple Sclerosis: A Prospective Study,” published by Ahmad, et al.

The researchers’ overarching goal was to quantify the prevalence of “critical” lesions in a tertiary care MS clinic’s patient population with progressive Multiple Sclerosis. In carefully selected cohorts of patients with demyelinating illness, “critical” demyelinating lesions are physically linked to increasing motor disability. From July 1, 2021, to March 31, 2022, participants will be enrolled in a prospective, observational cohort study of patients with progressive MS at the Mayo Clinic. Subspecialty, MS experts conducted a thorough neurological evaluation and analyzed all relevant clinical data and brain and spinal cord MRIs. Those with progressive multiple sclerosis were diagnosed with primary progressive motor, cognitive, cerebellar, or sensory impairment. Clinical progressive motor impairment was contrasted with MRI evaluation to identify patients with:  Progressive motor impairment is anatomically related to one or two “tandem” “critical” demyelinating lesions, which are typically located on the sides of the axial spinal cord and cause localized areas of atrophy.

A total of 196 MS patients were enrolled (126 with SPMS, 64.3%, and 70 with PPMS, 35.7%), with 128 already established at the MS clinic and 68 newly evaluated. Progressive motor impairment was the primary symptom in 181 (92.3%) patients, followed by ataxia in 13% and sensory dysfunction in 2.1%. About 76% of the 149 people with increasing motor impairment had a lesion burden too high to pinpoint the cause of their motor decline. Of 47 (24%), a focal “critical” lesion was identified physically as the cause of progressive motor impairment (38 (19.4%) had one “critical,” and 9 (4.6%) had two “tandem” “critical” lesions). The cervical spinal cord’s lateral column was the most common location for “critical” demyelinating lesions. About 24% of people with progressing MS have anatomically identifiable “critical” demyelinating lesions linked to motor disability. Those with progressive motor impairment due to MS may benefit from targeting “critical” demyelinating lesions as a prognostic and therapeutic target.