A new look at an old test: Normative data of the symbol digit modalities test –Oral version

Abstract

Background: The Symbol Digit Modalities Tests (SDMT) is the most sensitive measure to multiple sclerosis (MS)related cognitive dysfunction. However, existing normative data has been under scrutiny. Specifically, they are outdated, do not take into account gender, and are poorly stratified by education. More importantly, there exists no oral only version norms, which is typical administration among individuals with MS. Objective: The present investigation aimed to develop updated normative data of the oral version SDMT in which age, gender, and education were taken into consideration. Methods: A total of 675 healthy individuals, stratified by age, gender, and education completed the oral version SDMT. Results: Significant effects were found for age, gender, and education, consistent with previous contentions. Specifically, performance on the SDMT tends to decline with age, with the most noticeable decline beginning in the third decade of life and continuing into the sixth decade. Women, in general perform better than men, with an average of 5.1 more points. Finally, education effects were apparent among those aged 25-54. Conclusion: Based on these findings, updated normative data are provided. Utilization of these updated norms will result in a much needed and more accurate assessment of processing speed for individuals with MS.

Effect of Ozanimod on Symbol Digit Modalities Test Performance in Relapsing MS

“…SDMT scores were lower at baseline among men. Furthermore, normative scores on the oral SDMT in healthy volunteers are significantly (p < 0.001) lower for men than women (Strober et al, 2020). The previously published primary analysis of SUNBEAM did not show a significant variation in ozanimod efficacy by gender, based on ARR, new/enlarging T2 lesion count, or GdE lesion count (Comi et al, 2019).…”

“…Normative scores in a (non-MS) general community population <40 years of age ranged from 50-58 for written responses and 59-66 for oral responses (Sheridan et al, 2006). Scores tend to decrease with age and are influenced by education and gender (Sheridan et al, 2006;Strober et al, 2020). Updated normative values for the oral SDMT range from 55-68 in men aged 18-54 years, and 60-70 in women in the same age range (Strober et al, 2020).…”

“…Scores tend to decrease with age and are influenced by education and gender (Sheridan et al, 2006;Strober et al, 2020). Updated normative values for the oral SDMT range from 55-68 in men aged 18-54 years, and 60-70 in women in the same age range (Strober et al, 2020). A score change of ≥4 points is considered clinically meaningful .…”

Strengthening Mental Abilities with Relational Training (SMART) in Multiple Sclerosis (MS): Study Protocol for a Feasibility Randomised Controlled Trial

“…The SDMT (37) is a symbol substitution test that examines processing speed and attention and is reported as the most sensitive test for MS cognitive problems (38) . Age-, education-, and gender-adjusted norms are available (39) , and these will be used to de ne cognitive impairment (for study-eligibility) as: scoring 1.5 SDs or more below the normative reference-value.…”

Life satisfaction prevents decline in working memory, spatial cognition, and processing speed: Latent change score analyses across 23 years

“…In the current study, the SDM test showed strong betweenperson (α = .90-.92) and within-person reliability (α = .90). Furthermore, it has shown strong 2-week retest reliability (r = .74), convergent and discriminant validity, with scores of measures of different constructs [71][72][73].…”