The research was presented at the 4th Congress of the European Academy of Neurology (EAN), recently held in Lisbon, in the oral presentation “Spinal cord area is a stronger predictor of physical disability than brain volume in secondary progressive multiple sclerosis.”
MS patients progressively lose neurons in the spinal cord due to demyelination, or loss of the protective layer of nerve fibers called myelin.
Prior research reported contradictory results regarding the assessment of spinal cord atrophy (shrinkage) as a predictor of clinical disability in MS. Although scientists suggested that changes in the spinal area could be used to monitor disease progression and treatment effects, a 2017 study reported otherwise.
In turn, recent evidence showed that atrophy — the disappearance or shrinking — of brain lesions correlates with physical disability in MS, particularly the loss of lesion volume with that volume being replaced by cerebrospinal fluid (the liquid filling the brain and spinal cord).
The scientists compared measures of spinal cord and brain atrophy, looking particularly at their sensitivity in assessing disability progression in SPMS. The study included 60 SPMS patients (mean age 53.8, 37 men), participants in the MS-SMART Phase 2 trial (NCT01910259) taking place in the U.K. Patients’ mean disease duration was 23.4 years.
Participants underwent neurological evaluations, as well as brain and spinal cord magnetic resonance imaging (MRI) scans. Specifically, the researchers measured the mean upper cervical-cord cross-sectional area (MUCCA) and normalized brain volume (NBV), a common practice to reduce brain volume variation across patients.
They also assessed patients using the expanded disability status scale (EDSS), a widely used tool to quantify disability in MS; the MS functional composite (MSFC), a three-part outcome measure for MS clinical trials; and the Symbol Digit Modalities Test (SDMT), a screening instrument to detect cognitive impairment.
The study explored whether MRI variables correlated with clinical scores.
Results revealed that atrophy in both the spinal cord area and in brain volume was associated with EDSS and SDMT. However, only changes in measures of the spinal cord were linked to changes in MSFC scores.
Subsequent analysis showed that while the spinal cord area was the strongest predictor of EDSS, brain volume was the strongest predictor of SDMT.
“Our findings demonstrate that spinal cord area shows increasing promise as a marker of disability in progressive disease,” the researchers concluded.