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

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

The association between age and inflammatory disease activity on MRI in relapse-onset multiple sclerosis during long-term follow-up

BACKGROUND: Inflammatory disease activity in multiple sclerosis (MS) decreases with advancing age. Previous work found a decrease in contrast enhancing lesions (CELs) with age. Here we describe the relation of age and MRI measures of inflammatory disease activity during long-term follow-up in a large real-world cohort of people with relapse-onset MS. METHODS: We investigated MRI data from the long-term observational Amsterdam MS cohort. We used logistic regression models and negative binomial generalized estimating equations to investigate the associations between age and radiological disease activity after a first clinical event. RESULTS: We included 1,063 participants, and 10,651 cranial MRIs. Median follow-up time was 6.1 years (IQR 2.4-10.9 years). Older participants had a significantly lower risk of CELs on baseline MRI (40-50 years vs. 50 years vs. 50 years vs. 50 years, a less aggressive treatment strategy might be appropriate compared to younger patients