“Risdiplam treatment results in motor function improvement mainly in younger patients with spinal muscular atrophy(SMA), followed by stabilization. However, daily clinical practice teaches that adult patients, even with long disease duration, report unexpected motor improvements.
We followed 12 SMA type 2(58%) or 3(42%) patients, aged 16 to 58 years old(median 30.5), before to start risdiplam(T0) and after 6(T6,N=12) and 12 months(T12,N=8) with a multidimensional approach. We assessed motor function with the Hammersmith-Functional-Motor-Scale-Expanded (HFMSE),the Revised-Upper-Limb-Module (RULM) and the 32-item Motor-Function-Measure (MFM-32), in these scales higher scores indicate better function with a maximum score of 66, 37 and 96 respectively. A score change of 2 points in HFMSE and RULM and of 3 points in MFM-32 has been considered clinically meaningful in natural history studies.
At baseline, all patients showed low scores at HFMSE (mean 8.17,SD:12.36), RULM (mean 13.42,SD:10.6) and MFM-32 (mean 28.75,SD:20.34).At the HFMSE none, with one exception, had a clinically meaningful increase at T6 or T12. At the RULM none showed changes at T6, although 3/8 patients had an improvement of 2 points at T12. Interesting, all but one patient, showed an improvement when assessed by the MFM-32 scale, with a clinically meaningful increase in the total score in 2/12 patients at T6 and 6/8 patients at T12.
Although the administration of the MFM-32 is time consuming, this tool, composed by more items exploring tasks also achievable by weaker patients, might be more sensitive than other outcome measures to detect minimal functional changes in patients with a severe motor involvement”