The distribution and severity of lower-limb hypertonicity and spasticity differentially impacts walking speed in...

To investigate the relationship between the distribution and severity of hypertonicity and spasticity on walking speed in people with neurological injuries.

This cross-sectional observation cohort study used the Modified Ashworth Scale (MAS) and Modified Tardieu Scale (MTS) to assess hypertonicity and spasticity of the gastrocnemius, soleus, hamstrings and quadriceps. Participants were classified as having a distal (gastrocnemius and/or soleus), proximal (hamstrings and/or quadriceps) or mixed distribution of hypertonicity or spasticity. The 10-m walk test was used to quantify walking speed.

Seventy-five individuals with an adult-onset neurological condition participated. Those with a mixed distribution of hypertonicity or spasticity walked more slowly than those with a distal distribution. This finding was statistically significant when examining spasticity (0.54 vs 1.05 m/sec, p = 0.005), not hypertonicity (0.73 vs 1.05 m/sec, p = 0.162). The higher the severity score of hypertonicity or spasticity, the lower the walking speed. This finding was statistically significant when examining hypertonicity (r = -0.502, p < 0.001), but not spasticity (r = -0.171, p = 0.143).

The severity of hypertonicity demonstrated a relationship with walking speed, whereas the severity of spasticity did not. Results for the MAS and MTS are not interchangeable.