Real-world keystroke dynamics are a potentially valid biomarker for clinical disability in multiple sclerosis

K. H. Lam*, K. A. Meijer, F. C. Loonstra, E. M. E. Coerver, J. Twose, E. Redeman, B. Moraal, F. Barkhof, V. de Groot, B. M. J. Uitdehaag, J. Killestein

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

Abstract

Background: Clinical measures in multiple sclerosis (MS) face limitations that may be overcome by utilising smartphone keyboard interactions acquired continuously and remotely during regular typing. Objective: The aim of this study was to determine the reliability and validity of keystroke dynamics to assess clinical aspects of MS. Methods: In total, 102 MS patients and 24 controls were included in this observational study. Keyboard interactions were obtained with the Neurokeys keyboard app. Eight timing-related keystroke features were assessed for reliability with intraclass correlation coefficients (ICCs); construct validity by analysing group differences (in fatigue, gadolinium-enhancing lesions on magnetic resonance imaging (MRI), and patients vs controls); and concurrent validity by correlating with disability measures. Results: Reliability was moderate in two (ICC = 0.601 and 0.742) and good to excellent in the remaining six features (ICC = 0.760–0.965). Patients had significantly higher keystroke latencies than controls. Latency between key presses correlated the highest with Expanded Disability Status Scale (r = 0.407) and latency between key releases with Nine-Hole Peg Test and Symbol Digit Modalities Test (ρ = 0.503 and r = −0.553, respectively), ps < 0.001. Conclusion: Keystroke dynamics were reliable, distinguished patients and controls, and were associated with clinical disability measures. Consequently, keystroke dynamics are a promising valid surrogate marker for clinical disability in MS.

Original languageEnglish
Pages (from-to)1421-1431
Number of pages11
JournalMultiple Sclerosis
Volume27
Issue number9
Early online date5 Nov 2020
DOIs
Publication statusPublished - 1 Aug 2021

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