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Updated: Dec 26, 2025
Comprehensive Autopsy Program for Individuals with Multiple Sclerosis
Published on: July 19, 2019
Race, ethnicity, and cognition in persons newly diagnosed with multiple sclerosis
Lilyana Amezcua1, Jessica B Smith1, Edlin G Gonzales1
1From the Department of Neurology (L.A.), University of Southern California, Keck School of Medicine, Los Angeles; Department of Research & Evaluation (J.B.S., E.G.G.) and Los Angeles Medical Center, Department of Neurology (A.L.-G.), Southern California Permanente Medical Group, Pasadena; and Philadelphia College of Osteopathic Medicine (S.H.), PA.
Objective:
To determine whether black or Hispanic patients with newly diagnosed multiple sclerosis (MS) are more likely to have cognitive impairment than white patients when compared to controls matched on age, sex, and race/ethnicity. Whether black or Hispanic patients have a more aggressive MS disease course than white patients remains unclear. No prior studies have examined differences in early cognitive impairment. The oral Symbol Digit Modalities Test (SDMT) is sensitive to early cognitive impairment in MS but normative data in nonwhite patients are limited.
Methods:
We studied 1,174 adults who enrolled in the MS Sunshine Study. SDMT and verbal fluency were measured in 554 incident cases of MS or clinically isolated syndrome (CIS) and 620 matched controls. Multivariable regression was used to examine correlates of abnormal SDMT in the entire cohort.
Results:
The strongest independent predictors of lower oral SDMT scores in rank order were having MS/CIS, lower educational attainment, and being black or Hispanic. Black and Hispanic patients and controls had lower SDMT scores than white participants even after controlling for age, sex, and education. However, no interaction between race/ethnicity and MS case status on SDMT scores was detected. Easy-to-use reference scores stratified by age and educational attainment for black and Hispanic patients are provided.
Conclusion:
Persons with newly diagnosed MS/CIS are more likely to have subtly impaired cognitive function than controls regardless of race/ethnicity. Lower absolute SDMT scores among black and Hispanic patients compared to white patients highlight underlying US population differences rather than differences in MS disease severity.
Insights
Cognitive impairment in newly diagnosed multiple sclerosis (MS) affects all races equally. However, Black and Hispanic patients show lower Symbol Digit Modalities Test (SDMT) scores, reflecting population differences, not MS severity.
Area of Science:
- Neurology
- Neuroimmunology
- Cognitive Neuroscience
Background:
- Multiple sclerosis (MS) diagnosis is increasing, with cognitive impairment being a common symptom.
- Understanding cognitive differences across racial/ethnic groups in early MS is crucial for accurate assessment and management.
- Limited normative data exists for cognitive tests like the Symbol Digit Modalities Test (SDMT) in non-white populations.
Purpose of the Study:
- To compare cognitive impairment in newly diagnosed Black and Hispanic multiple sclerosis (MS) patients versus white patients.
- To investigate potential differences in MS disease course based on race/ethnicity.
- To establish normative data for the oral Symbol Digit Modalities Test (SDMT) in diverse populations.
Main Methods:
- A cohort of 1,174 adults from the MS Sunshine Study was analyzed.
- Cognitive function was assessed using the oral Symbol Digit Modalities Test (SDMT) and verbal fluency tests.
- Multivariable regression models were employed to identify predictors of cognitive impairment.
Main Results:
- Lower oral SDMT scores were independently predicted by having MS/clinically isolated syndrome (CIS), lower educational attainment, and belonging to Black or Hispanic racial/ethnic groups.
- Black and Hispanic participants, both with and without MS/CIS, exhibited lower SDMT scores compared to white participants, even after adjusting for covariates.
- No significant interaction was found between race/ethnicity and MS/CIS status on SDMT scores, suggesting population-level differences.
Conclusions:
- Newly diagnosed individuals with MS/CIS experience cognitive impairment compared to controls, irrespective of race/ethnicity.
- Observed lower SDMT scores in Black and Hispanic patients reflect broader demographic disparities in cognitive function rather than differences in MS disease severity.
- The study provides essential reference scores for the SDMT, stratified by age and education, for Black and Hispanic populations.
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