Assessing physical activity levels in people with multiple sclerosis: Should be used standardized or individualized cutoff?

Assessing and monitoring the level of physical activity in people with Multiple Sclerosis (PwMS) seems central as physical activity has been considered a main therapy for maintaining autonomy and improving quality of life in this population. One of the main strategies to evaluate objectively the level of physical activity of PwMS in an ecological context is the use of accelerometers. These on-board devices allow to easily convert physical measurement (acceleration) in a more intuitive outcome as the time doing moderate to vigorous physical activity (MVPA) by PwMS. The challenge in this conversion is the use of the appropriate cutoff as PwMS present different physical profiles. To overcome this problem, an interesting alternative should be the determination of personalized cutoffs. This study aimed to determine how much the measurement of the MVPA levels in PwMS differed when using a personalized and generic cutoff. The study was conducted on a group of 28 PwMS. An accelerometer was given to PwMS for use on their non-dominant hip for 14 days. They were instructed to wear it every day from waking up until bedtime. Data collected on the accelerometer were processed and time spending in MVPA was computed with a personalized and generic cutoff. Our findings revealed a difference of 78 % in measuring MVPA using a personalized and generic MVPA cutoff in PwMS. Given the crucial role of PA in managing multiple sclerosis, it seems important to better determine personalized MVPA cutoffs before the assessment of daily life performance of PwMS.