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Biomarkers and Bioinformatics Poster Presentation

P0146 - Reliability, concurrent and ecological validity of smartphone-based cognition and walking tests (ID 780)

Speakers
Presentation Number
P0146
Presentation Topic
Biomarkers and Bioinformatics

Abstract

Background

The early detection and monitoring of cognitive and ambulatory dysfunction in multiple sclerosis (MS) may be enhanced with smartphone-adapted cognition and walking tests. Contrary to clinical measures, smartphone-based assessment allows more frequent measurements in the everyday environment, which potentially better reflects daily functioning.

Objectives

To determine the reliability, concurrent and ecological validity of self-administered smartphone-adapted Symbol Digit Modalities Test (SDMT) and Two-Minute Walking Test (2MWT).

Methods

Patients with MS were recruited. At baseline the SDMT and Timed 25-foot Walk Test (T25FW) were assessed clinically. During a 28-day follow-up, patients used the MS sherpa® app to perform the smartphone SDMT and 2MWT three times a week. The smartphone SDMT was assessed through tapping numbers corresponding to symbols on the smartphone during 90 seconds. The 2MWT measured walking distance utilizing the smartphone built-in sensors during two minutes of normal walking. Reliability of the smartphone tests were assessed by calculating intra-class correlation coefficients (ICC) between scores from week 2 and 3. Concurrent validity was addressed by calculation of correlation coefficients between the smartphone tests and their clinical counterparts. MS sherpa® also included one-item self-report scores for perceived fatigue and impact of MS on daily functioning. To assess ecological validity, the temporal association between the MS sherpa® tests and self-report scores from the everyday environment were analyzed using linear mixed models with the repeated measures as random effects.

Results

102 patients with MS were included. During the 28-day follow-up 102 patients completed a mean (± SD) of 12.1 (± 6.8) SDMTs and 74 patients completed a mean (± SD) of 8.8 (± 6.1) 2MWTs. Smartphone SDMT correlated significantly with the clinical SDMT (r = 0.607, p < 0.001) and demonstrated excellent reliability (ICC = 0.923). 2MWT was significantly correlated with T25FW (ρ = -0.352, p = 0.001) and demonstrated good reliability (ICC = 0.845). Over the 28-day period, higher 2MWT scores were related with lower perceived impact of MS on daily functioning (b = -0.005, 95% CI [-0.010, -0.001]) and higher SDMT scores were related with lower perceived fatigue (b = -0.014, 95% CI [-0.026, -0.003]).

Conclusions

Smartphone-adapted cognition and walking tests can be assessed frequently from the participants’ own environment and demonstrated validity and reliability in assessment of information processing speed and ambulatory function in MS. Support for ecological validity was found for perceived fatigue and impact on functioning in the everyday environment.

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