Handgrip and finger flexion strength in children: A cross-sectional assessment of age-related normative data and application as a clinical functional marker in paediatric neuromuscular disorders

BackgroundThe aim of this study was to evaluate handgrip and finger flexion strength (HGFS) as functional marker for disease progression in children with neuromuscular disorders (NMD) and present normative data in a paediatric healthy cohort.MethodsWe applied the fixed hand and finger dynamometer HFD 200 to assess HGFS under standardised, isometric and biomechanical conditions. In our cross-sectional study HGFS was analysed in n = 233 paediatric healthy controls (HC) and a cohort of n = 33 children with NMD between five and 18 years. In seven children with spinal muscular atrophy (SMA), HGFS were assessed prior to and under treatment with nusinersen over a two months period. HGFS of children with NMD was correlated with respiratory parameters, anthropometric data, hand function and motor scores.ResultsPatients with NMD exhibited a heterogenous HGFS pattern. HGFS was lower than in HC (p < 0.001). Children with SMA gained a significant increase in strength after two months of treatment (p < 0.05, r = 0.75–0.9).ConclusionHGFS is a sensitive functional marker in paediatric NMD to identify minimal changes in distal muscle strength. HGFS may evolve as a sensitive outcome measure to monitor upcoming therapeutic interventions in particular for non-ambulant patients with NMD.