A continuous repetitive task to detect fatigability in spinal muscular atrophy

Abstract

Abstract 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 0.4). 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

• Neuromuscular disease
• Spinal muscular atrophy
• SMA
• Clinical neurology
• Fatigability
• Outcome measure