Postural assessment in hereditary spastic paraparesis

Hereditary spastic paraparesis (HSP) is a heterogeneous group of neurodegenerative disorders, characterized by spasticity and weakness of the lower limbs, which may perturb the balance control. Purpose of this study was to quantify postural stability in HSP children. We tested 5 children with HSP and 5 healthy participants (H). Kinematic data were recorded with an optoelectronic system and a full body marker set, allowing to directly determine the Centre of Mass (CoM). Two force plates measured the centre of pressure of each foot (CoP_LEFT, CoP_RIGHT), as well as the body weight distribution between feet. Participants were asked to stand barefoot for 30 seconds, with their big toes aligned on a transverse line drawn on the force plates. Three trials were performed, both with eyes open (EO) and closed (EC). Preliminary results showed that, in both visual conditions, whole-body CoP was shifted about 15 mm toward forefoot in HSP, with a larger asymmetry between CoP_LEFT and CoP_RIGHT (13.9 mm in HSP vs. 8.5 mm in H), as well as in weight distribution (4.4% in HSP vs. 2.3% in H). Moreover, in EO, the anterior-posterior range of CoP and CoM was larger in HSP (+53% and +72%, respectively), while changes with EC were inconsistent. Present results need to be statistically confirmed on a larger sample and future experiments will also address different paediatric motor disorders, to ascertain if disease specific hallmarks may be identified.