General movements in spinal muscular atrophy type 1

ABSTRACT

Purpose

To investigate the motor repertoire of infants diagnosed with spinal muscular atrophy Type I (SMA Type I) without administration of any disease-modifying agent.

Methods

Motor Optimality Score-Revised (MOS-R) was calculated from videos recorded between post-term weeks 9–17 for 22 infants with SMA Type I. The MOS-R of infants with SMA Type I was compared with those of 22 infants with cerebral palsy (CP) and 22 infants with typical development.

Results

Of the infants with SMA Type I, 17 had absent fidgety movements (FMs) and 5 had sporadic FMs. Age adequate movement repertoire was absent, and the variety of movements in infants was very low. Movements were symmetrical but movements of four limbs remained on the surface level. Antigravity movements were very rare. Movement characterization was monotonous, slow speed, and small amplitude. The MOS-R of infants with SMA Type I was lower than those of infants with typical development but similar to those of infants with CP.

Conclusions

Infants with SMA Type I had a motor repertoire similar to infants with CP, while they had a poorer motor repertoire than infants with typical development in the fidgety period as evidenced by MOS-R. Central nervous system involvement in these infants with SMA Type I with absent FMs and reduced MOS-R is unknown. Further studies are needed to determine the role of problems in the afferent and efferent pathways of spinal cord and muscle atrophy in the observation of normal FMs.

KEYWORDS:

• Spinal muscular atrophy
• general movement assessment
• motor repertoire

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

The author(s) reported that there is no funding associated with the work featured in this article.