Control of the upper body movements during level walking in patients with facioscapulohumeral dystrophy.

Facioscapulohumeral dystrophy (FSHD) is a muscular disease usually spreading from upper to lower body and characterised by asymmetric muscle weakness. Walking ability is compromised in these patients, with a consequent high risk of falls. A quantitative analysis of the upper body oscillations may unveil useful information about the capacity of these patients to stabilise the head, maintain balance, and compensate for lower limb muscle weakness during walking. This study involved 13 patients with FSHD and 13 healthy volunteers. The trajectories of three points located on the cranio-caudal axis, at head, shoulder, and pelvis levels, during level walking, were analysed. The range of motion of these three points and the attenuation of the relevant accelerations going from pelvis to head level were used to describe the upper body movements during walking. The patients had wider and less symmetrical oscillations than the healthy controls both in antero-posterior and medio-lateral directions. Furthermore, the capacity of the patients to attenuate the accelerations going from pelvis to head level was reduced. These features may be related not only to upper body muscle weakness, but also to a strategy functional to the compensation of proximal leg muscle weakness. In conclusion, this study highlighted that the control of upper body oscillations and of head stability is reduced in patients with FSHD, suggesting that the assessment of the upper body movements should be included in the treatment decision process.