Understanding Tools to Assess Aerobic Capacity, Physical Activity in Spinal Muscular Atrophy: Jacqueline Montes, PT, EdD

WATCH TIME: 4 minutes

"Because of this sort of range of ability, phenotype, and age, we have outstanding measures for certain groups, and then there are gaps in others. One gap that is not solved by CPET is for the very weak, those with minimal motor function, where capturing the change they might be experiencing isn’t so easy. Or at least our standard tools aren’t designed to measure them.”

Since its approval in 2016, approximately 3700 adults with spinal muscular atrophy (SMA) have been treated with nusinersen (Spinraza; Novartis) worldwide. Several studies have demonstrated clinically meaningful improvements on core assessments of motor function; however, few have reported on the effects of nusinersen on aerobic capacity or physical activity. Aerobic capacity is a measure of cardiorespiratory fitness, defined as the peak oxygen update during intense or maximal exercise, whereas physical activity is any bodily movement produced by skeletal muscles that requires energy expenditure.

An analysis conducted by Jacqueline Montes, PT, and others, aimed to assess changes in these outcomes for patients treated with nusinersen over a 6-month period, using post hoc trial data. All told, there were no improvements in function, as measured by 6-minute walking test distance, fatigue, or muscle oxygen uptake over the treatment period. Additionally, there were observed improvements in aerobic capacity (mean change, 27.3%) in nusinersen-treated adults not previously observed in a controlled trial of aerobic exercise (mean change, 2.3%). While not significant, there was a trend in increases in percentage of predicted maximal heart rate during the Cardiopulmonary Exercise Tolerance Test (CPET).

CPET, along with the International Physical Activity Questionnaire–Short Form (IPAQ-SF), were the 2 main methods used to assess changes in aerobic capacity and physical activity. Montes, an associate professor of rehabilitation and regenerative medicine at Columbia University, sat down with NeurologyLive^® to discuss the reasons behind using these assessment tools, as well as whether the available measures do a sufficient enough job at capturing physical and motor capacity.