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Smartphone-based symbol-digit modalities test reliably captures brain damage in multiple sclerosis.

ABSTRACT: As the burden of neurodegenerative diseases increases, time-limited clinic encounters do not allow quantification of complex neurological functions. Patient-collected digital biomarkers may remedy this, if they provide reliable information. However, psychometric properties of digital tools remain largely un-assessed. We developed a smartphone adaptation of the cognitive test, the Symbol-Digit Modalities Test (SDMT) by randomizing the test's symbol-number codes and testing sequences. The smartphone SDMT showed comparable psychometric properties in 154 multiple sclerosis (MS) patients and 39 healthy volunteers (HV). E.g., smartphone SDMT achieved slightly higher correlations with cognitive subscores of neurological examinations and with brain injury measured by MRI (R²?=?0.75,?Rho?=?0.83, p?

SUBMITTER: Pham L

PROVIDER: S-EPMC7904910 | biostudies-literature | 2021 Feb

REPOSITORIES: biostudies-literature

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Smartphone-based symbol-digit modalities test reliably captures brain damage in multiple sclerosis.

Pham Linh L Harris Thomas T Varosanec Mihael M Morgan Vanessa V Kosa Peter P Bielekova Bibiana B

NPJ digital medicine 20210224 1

As the burden of neurodegenerative diseases increases, time-limited clinic encounters do not allow quantification of complex neurological functions. Patient-collected digital biomarkers may remedy this, if they provide reliable information. However, psychometric properties of digital tools remain largely un-assessed. We developed a smartphone adaptation of the cognitive test, the Symbol-Digit Modalities Test (SDMT) by randomizing the test's symbol-number codes and testing sequences. The smartpho ...[more]

PMID: 33627777

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Project description:BackgroundThe decline of cognitive processing speed (CPS) is a common dysfunction in persons with multiple sclerosis (MS). The Symbol Digit Modalities Test (SDMT) is widely used to formally quantify CPS. We implemented a variant of the SDMT in MS sherpa, a smartphone app for persons with MS.ObjectiveThe aim of this study was to investigate the construct validity and test-retest reliability of the MS sherpa smartphone variant of the SDMT (sSDMT).MethodsWe performed a validation study with 25 persons with relapsing-remitting MS and 79 healthy control (HC) subjects. In the HC group, 21 subjects were matched to the persons with MS with regard to age, gender, and education and they followed the same assessment schedule as the persons with MS (the "HC matched" group) and 58 subjects had a less intense assessment schedule to determine reference values (the "HC normative" group). Intraclass correlation coefficients (ICCs) were determined between the paper-and-pencil SDMT and its smartphone variant (sSDMT) on 2 occasions, 4 weeks apart. Other ICCs were determined for test-retest reliability, which were derived from 10 smartphone tests per study participant, with 3 days in between each test. Seven study participants with MS were interviewed regarding their experiences with the sSDMT.ResultsThe SDMT scores were on average 12.06% higher than the sSDMT scores, with a standard deviation of 10.68%. An ICC of 0.838 was found for the construct validity of the sSDMT in the combined analysis of persons with MS and HC subjects. Average ICCs for test-retest reliability of the sSDMT for persons with MS, the HC matched group, and the HC normative group were 0.874, 0.857, and 0.867, respectively. The practice effect was significant between the first and the second test of the persons with MS and the HC matched group and trivial for all other test-retests. The interviewed study participants expressed a positive attitude toward the sSDMT, but they also discussed the importance of adapting a smartphone cognition test in accordance with the needs of the individual persons with MS.ConclusionsThe high correlation between sSDMT and the conventional SDMT scores indicates a very good construct validity. Similarly, high correlations underpin a very good test-retest reliability of the sSDMT. We conclude that the sSDMT has the potential to be used as a tool to monitor CPS in persons with MS, both in clinical studies and in clinical practice.

Project description:Outcome measures to capture disability, such as the Multiple Sclerosis Functional Composite (MSFC), were developed to enhance outcome measurements for clinical trials in adults with multiple sclerosis (MS). The MSFC initially included three components: a timed 25-foot walk [T25FW], 9-hole peg test [9HPT], and the Paced Auditory Serial Addition Task [PASAT]. Modifications to the original MSFC, such as adding binocular low-contrast letter acuity (LCLA) or substituting the symbol digit modalities test (SDMT) for the PASAT, improved the capacity to capture neurologic impairment in adults. Similar outcome scales for pediatric MS have not yet been established.To determine whether the three-component MSFC or a modified MSFC with LCLA and the SDMT better identifies neurological deficits in pediatric MS.We evaluated 5 measures (T25FW, 9HPT, Children's PASAT [ChiPASAT], SDMT, and binocular LCLA [Sloan charts, 1.25% contrast]) in children with MS (disease onset <18 years) and healthy controls. To be able to compare measures whose scores have different scales, Z-scores were also created for each test based on the numbers of standard deviations from a control group mean, and these individual scale scores were combined to create composite scores. Logistic regression models, accounting for age, were used to determine whether the standard 3-component MSFC or modified versions (including 4 or 5 metrics) best distinguished children with MS from controls.Twenty pediatric-onset MS subjects, aged 6-21 years, and thirteen healthy controls, aged 6-19 years, were enrolled. MS subjects demonstrated worse scores on the 9HPT (p=0.004) and SDMT (p=0.001), but not the 25FTW (adjusted for height, p=0.63) or the ChiPASAT (p=0.10): all comparisons adjusted for age. Decreased (worse) binocular LCLA scores were associated with MS (vs. control status, p=0.03, logistic regression; p=0.08, accounting for age). The MSFC composite score for the traditional 3 components did not differ between the groups (p=0.28). Replacing the ChiPASAT with the SDMT (OR 0.72, p=0.05) better distinguished MS from controls. A modified MSFC-4 with the SDMT replacing the ChiPASAT and including binocular 1.25% LCLA had the greatest capacity to distinguish pediatric MS from controls (OR 0.89, p=0.04, logistic regression). Including all 5 metrics as a composite MSFC-5 did not improve the model (p=0.18).A modified MSFC (25FTW, 9HPT, SMDT, and binocular 1.25% LCLA) is more sensitive than the traditional MSFC or its components to capture the subtle impairments that characterize pediatric MS and should be validated in order to be considered for future pediatric MS trials.

Project description:BackgroundIncorporating cognitive testing into routine clinical practice is a challenge in multiple sclerosis (MS), given the wide spectrum of both cognitive and physical impairments people can have and the time that testing requires. Shortened paper and verbal assessments predominate but still are not used routinely. Computer-based tests are becoming more widespread; however, changes in how a paper test is implemented can impact what exactly is being assessed in an individual. The Symbol Digit Modalities Test (SDMT) is one validated test that forms part of the cognitive batteries used in MS and has some computer-based versions. We developed a tablet-based SDMT variant that has the potential to be ultimately deployed to patients' own devices.ObjectiveThis paper aims to develop, validate, and deploy a computer-based SDMT variant, the Cognition Reaction (CoRe) test, that can reliably replicate the characteristics of the paper-based SDMT.MethodsWe carried out analysis using Pearson and intraclass correlations, as well as a Bland-Altman comparison, to examine consistency between the SDMT and CoRe tests and for test-retest reliability. The SDMT and CoRe tests were evaluated for sensitivity to disability levels and age. A novel metric in CoRe was found: question answering velocity could be calculated. This was evaluated in relation to disability levels and age for people with MS and compared with a group of healthy control volunteers.ResultsSDMT and CoRe test scores were highly correlated and consistent with 1-month retest values. Lower scores were seen in patients with higher age and some effect was seen with increasing disability. There was no learning effect evident. Question answering velocity demonstrated a small increase in speed over the 90-second duration of the test in people with MS and healthy controls.ConclusionsThis study validates a computer-based alternative to the SDMT that can be used in clinics and beyond. It enables accurate recording of elements of cognition relevant in MS but offers additional metrics that may offer further value to clinicians and people with MS.

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Smartphone-based symbol-digit modalities test reliably captures brain damage in multiple sclerosis.

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Smartphone-based symbol-digit modalities test reliably captures brain damage in multiple sclerosis.

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