Symbol Digit Modalities Test Variant in a Smartphone App for Persons With Multiple Sclerosis: Validation Study

Area of Science:

• Neurology
• Digital Health
• Cognitive Neuroscience

Background:

• Cognitive processing speed (CPS) decline is a common issue in multiple sclerosis (MS).
• The Symbol Digit Modalities Test (SDMT) is a standard tool for assessing CPS.
• A smartphone application (MS sherpa) was developed to implement a variant of the SDMT.

Purpose of the Study:

• To evaluate the construct validity of the smartphone SDMT variant (sSDMT).
• To assess the test-retest reliability of the sSDMT.
• To explore user experiences with the sSDMT in individuals with MS.

Main Methods:

• A validation study involved 25 individuals with relapsing-remitting MS and 79 healthy controls (HC).
• Construct validity was assessed by comparing sSDMT scores with the paper-and-pencil SDMT.
• Test-retest reliability was determined through repeated sSDMT assessments over time.

Main Results:

• The sSDMT demonstrated strong construct validity with a high intraclass correlation coefficient (ICC) of 0.838.
• Excellent test-retest reliability was observed across different participant groups (MS, HC matched, HC normative) with ICCs ranging from 0.857 to 0.874.
• Participants reported a positive experience with the sSDMT, emphasizing the need for user-centered adaptation.

Conclusions:

• The sSDMT exhibits robust construct validity and test-retest reliability.
• The sSDMT is a promising tool for monitoring cognitive processing speed in MS.
• The sSDMT can be utilized in both clinical research and practice for individuals with MS.