Longitudinal changes in respiratory and upper limb function in a pediatric type III spinal muscular atrophy cohort after loss of ambulation

Abstract

Introduction/Aims Spinal muscular atrophy (SMA) type III is a relatively mild form of SMA. Few studies have investigated the changes in both respiratory and upper limb function within this population after loss of ambulation. The aim of this study was to assess change in percentage of predicted forced vital capacity (FVC% predicted) and change in the Revised Upper Limb Module (RULM) score in these patients throughout a 24‐month period after loss of ambulation. Effect of scoliosis and its surgical correction, disease duration since loss of ambulation, weight, and height were also investigated. Methods Retrospective analyses were performed on 24 nonambulant SMA III patients from data collected at two centers in the United Kingdom. Results The FVC% predicted score showed a significant progressive deterioration of 17% over the 24‐month period. Respiratory deterioration correlated significantly with age, weight, disease duration since loss of ambulation, and spinal correctional surgery. Longitudinal RULM data were available for 16 patients; a significant deterioration was observed with a mean decrease in score of 3 over 24 months. Age correlated negatively with RULM score, as did height and time since loss of ambulation. A significant positive correlation between FVC% predicted and RULM was demonstrated. Discussion This study highlights how SMA type III patients have progressive deterioration of respiratory and upper limb function after loss of ambulation. Combining data from these assessments could provide insight into clinical progression, inform clinical trials, and provide assistance in managing disease progression expectations for patients.

Assessment of the upper limb function, strength, and mobility in treatment‐naive children with spinal muscular atrophy Types 2 and 3

“…Our results confirms the limitations of the RULM scale for the ambulant SMA Type 3 children, where most of the patients showed no change in score over the year. We recognize that a 24‐month or longer follow‐up period in a larger cohort would be better suited to detect changes in this population as also previously suggested by others 5,10,22 …”

“…Our results confirms the limitations of the RULM scale for the ambulant SMA Type 3 children, where most of the patients showed no change in score over the year. We recognize that a 24-month or longer follow-up period in a larger cohort would be better suited to detect changes in this population as also previously suggested by others 5,10,22. While the RULM scale provides an indication of the overall motor function in the upper limbs, high precision dynamometry provides an additional assessment of hand muscle strength allowing more subtle changes to be captured in an interval of time during which RULM changes do not occur.…”

Examination of Upper Limb Function and the Relationship with Gross Motor Functional and Structural Parameters in Patients with Spinal Muscular Atrophy

“…In the case of the HFMSE, the increase was 1.9 points according to Coratti and 1.6 points in SMA2 and 0.9 points in SMA3 in Pane’s publication. However, only a few papers reported an improvement in the treated SMA patients, whereas the data were dominated by the deterioration ranging from 0.13 to as much as 3 points on the RULM scale and about 0.5 points on the HFMSE scale [ 9 , 11 , 24 , 25 , 26 ]. This is most likely due to the later initiation of treatment and the large deficits that have already occurred.…”

The Association between the Respiratory System and Upper Limb Strength in Males with Duchenne Muscular Dystrophy: A New Field for Intervention?

“…The next interesting result of our study showed that MIP, MEP, HGS, and PUL values were characterized by a high standard deviation. Meier et al reported high coefficients of variability for MIP (18%) and MEP (15%), irrespective of age, in a group of 64 DMD patients, aged 10–18 years [ 32 ]. The cited study concluded that patients have difficulty regarding the reproducibility of the measurements.…”