Two researchers from Chungbuk National University Hospital of Korea have discovered that children with spinal muscular atrophy (SMA) type 2 demonstrated improvements in fine manual dexterity after nusinersen treatment, according to a study published in Neuromuscular Disorders in Children and Adolescents.

Nusinersen is a treatment that targets defective survival motor neuron (SMN) genes. “Previous research has consistently demonstrated that nusinersen treatment improves both gross motor function as measured using the Hammersmith Functional Motor Scale (expanded version) (HFMSE) and upper extremity motor function as measured using the Revised Upper Limb Module (RULM) in patients with later-onset SMA,” Gu and Kong wrote. 

However, a detailed study focusing on improvements in fine manual dexterity, such as picking up coins or tearing a piece of paper, has not been conducted. The research team hence decided to investigate the effects of nusinersen on fine manual dexterity in SMA type 2 patients.


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They recruited 5 patients with SMA type 2 and administered nusinersen intrathecally at the 12 mg dose on day 0, day 14, day 28, and day 63, then every 4 months for maintenance. Patients were evaluated for functional ability, including fine manual dexterity, before starting treatment, between the 3rd and 4th dose, and before nusinersen administration during the maintenance period. 

Using the HFMSE and Purdue Pegboard (PP) tests, patients demonstrated functional improvements after the administration of nusinersen according to the protocol described (the PP test specifically assesses for hand functional movement). The researchers reported, “Changes in PP scores from baseline to 18 months confirmed that nusinersen treatment improved fine manual dexterity in patients with SMA type 2.” 

Further studies could possibly involve recruiting different types of SMA patients to study the effects of nusinersen on their fine manual dexterity.

“Since this study was conducted only on patients with SMA type 2, the effect of nusinersen on fine manual dexterity in patients with other subtypes of SMA could not be identified,” the researchers noted.

Reference

Gu M, Kong H-H. Improvement in fine manual dexterity in children with spinal muscular atrophy type 2 after nusinersen injection: A case seriesChildren. Published online November 11, 2021. doi:10.3390/children8111039