Progression independent of relapse activity can be predicted by passively acquired tapping speed through a smartphone for 1 month: A prospective study

Background: Tapping speed (TS) correlates with baseline disability scales in people with multiple sclerosis (pwMS)Objective: The study aimed to address if progression independent of relapse activity (PIRA) could be predicted by first-month measurement of TS. Methods: Prospective study including pwMS in one referral MS center. Consecutive patients were included and keys/second (Keys/s) were passively measured each day using an in-house smartphone application for 1 month. Median, mean, and maximum keys/s were obtained. Multivariate logistic regression models (including keys/s, age, sex, and baseline disability scores) were obtained for prediction of a PIRA event after 1 year. Results: Overall, 59 patients were included in the final analysis (64.4% women, median age of 44.5 years). However, 10 patients presented a PIRA event, without differences regarding baseline characteristics between PIRA and no-PIRA groups. PIRA group presented lower median keys/s (2 vs 4 keys/s, p = 0.002) and mean keys/s (2.8 vs 4.6, p = 0.008), while maximum keys/s were similar (p = 0.32). A median <= 3 keys/s was independently associated with PIRA (aOR = 16.8, p = 0.03), as did a mean <= 3.7 keys/s (aOR = 17, p = 0.02). These differences were not detected regarding other variables analyzed. Conclusion: Low median or mean keys/s obtained during initial month of assessment were indicative of a PIRA event within the next year.