A continuous repetitive task to detect fatigability in spinal muscular atrophy

Orphanet J Rare Dis. 2018 Sep 12;13(1):160. doi: 10.1186/s13023-018-0904-5.


Background: To determine the value of a continuous repetitive task to detect and quantify fatigability as additional dimension of impaired motor function in patients with hereditary proximal spinal muscular atrophy (SMA).

Results: In this repeated measure case-control study 52 patients with SMA types 2-4, 17 healthy and 29 disease controls performed five consecutive rounds of the Nine-Hole Peg test to determine the presence of fatigability. We analysed differences in test performance and associations with disease characteristics. Five patients with SMA type 2 (22%) and 1 disease control (3%) could not finish five rounds due to fatigue (p = 0.01). Patients with SMA type 2 performed the test significantly more slowly than all other groups (p < 0.005) and disease controls were slower than healthy controls (p < 0.05). Patients with SMA type 2 performed round five 27% slower than round one, while healthy controls performed round five 14% faster than round one (p = 0.005). There was no difference between SMA type 3a, type 3b/4 or disease controls and healthy controls (p > 0.4). Time needed to complete each round during the five-round task increased in 15 patients with SMA type 2 (65%), 4 with type 3a (36%), 4 with type 3b/4 (22%), 9 disease controls (31%) and 1 healthy control (6%). There was no effect of age at disease onset or disease duration in SMA type 2 (p = 0.39). Test-retest reliability was high.

Conclusion: Fatigability of remaining arm function is a feature of SMA type 2 and can be determined with continuous repetitive tasks.

Keywords: Clinical neurology; Fatigability; Neuromuscular disease; Outcome measure; Repeated nine-hole peg test; SMA; Spinal muscular atrophy; r9HPT.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Case-Control Studies
  • Child
  • Diagnostic Tests, Routine / methods*
  • Fatigue / diagnosis*
  • Fatigue / physiopathology*
  • Female
  • Humans
  • Male
  • Middle Aged
  • Muscular Atrophy, Spinal / diagnosis*
  • Muscular Atrophy, Spinal / physiopathology*
  • Reproducibility of Results
  • Spinal Muscular Atrophies of Childhood / diagnosis
  • Spinal Muscular Atrophies of Childhood / physiopathology
  • Young Adult