Using the Hammersmith Functional Motor Scale Expanded (HFMSE) and the Revised Upper Limb Module (RULM) in combination could increase the sensitivity of detecting clinically meaningful changes in motor function in patients with spinal muscular atrophy (SMA) types 2 and 3. This is according to a new study by Giorgia Coratti PT, MsC, and colleagues published in the journal Muscle & Nerve.
The HFMSE and RULM are widely used in natural history studies, as well as clinical trials to assess motor function in patients with SMA and other neuromuscular conditions.
To establish how the scales relate to each other at different age points in SMA type 2 and 3, a team of researchers led by Eugenio Mercuri MD, PhD, from Università Cattolica del Sacro Cuore in Rome, Italy, reanalyzed previously published data about the natural history of SMA from 364 patients with the disease.
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The patients showed different trends in score and point of slope change for the 2 scales. For type 2 disease, the point of slope change was 4.1 years for the HFMSE and 5.8 years for the RULM. On the other hand, for type 3 disease, the point of slope change was 6 years for the HFMSE and 7.3 years for the RULM.
Of the 364 patients, 121 had 2 or more assessments at the 12-month mark. The longitudinal analysis of the 12-month changes also included the analysis of concordance between scales. Changes were grouped as stable, improved, or declined.
Full concordance was found in more than half (57.3%) of the assessments. In 40.4% of them, one scale remained stable and the other changed. Each scale appeared to be more sensitive to specific age or functional subgroups.
“The two scales, when used in combination, may increase the sensitivity to detect clinically meaningful changes in motor function in patients with SMA types 2 and 3,” the researchers reported.
Coratti G, Pera MC, Montes J, et al. Different trajectories in upper limb and gross motor function in spinal muscular atrophy. Muscle Nerve. Published online July 30, 2021. doi:10.1002/mus.27384