Gastrocnemius and soleus spasticity and muscle length in Friedreich's ataxia

Lower limb spasticity compromises the independence of people with Friedreich's ataxia (FRDA). This study sought to examine lower limb spasticity in FRDA in order to offer new insight as to the best approach and timing of spasticity management. Gastrocnemius and soleus spasticity and muscle length were measured by the Modified Tardieu Scale (MTS) in 31 participants with typical and late-onset FRDA. Relationships between the MTS and the Friedreich Ataxia Rating Scale (FARS), Functional Independence Measure (FIM), and disease duration were analysed. Differences between ambulant (n = 18) and non-ambulant (n = 13) participants were also examined. All participants had spasticity in at least one muscle, and 38.9% of ambulant and 69.2% of non-ambulant participants had contracture in one or both of their gastrocnemius muscles. Significant negative correlations were found between both gastrocnemius and soleus angle of catch and the FARS score. The FIM score also demonstrated significant correlations with gastrocnemius muscle length and angle of catch. Gastrocnemius and soleus spasticity and contracture is apparent in people with FRDA. Spasticity is evident early in the disease and in ambulant participants. Management of spasticity and reduced muscle length should be considered in people with FRDA at disease onset to optimise function.