Quantitative assessment of alterations induced by spasticity on gait of individuals with multiple sclerosis using 3D gait analysis

Background: Among the spectrum of symptoms associated with multiple sclerosis (MS), spasticity represents one of the most commonly observed. While a wide range of pharmacological and rehabilitative treatments are available to manage the negative consequences of spasticity, there are still some unresolved issues that regard in particular the actual impact of such therapies on the functions possibly impaired. Aims: This study aims to assess quantitatively the impact of spasticity on gait in people with MS using 3D gait analysis from which kinematic, spatial-temporal (ST) and muscular activation (EMG) data will be extracted. Methods: Nineteen patients with relapsing-remitting MS (12 women, seven men, mean age 54.6±9.5 years) with an Expanded Disability Status Scale (EDSS) score in the range 3.5–6.5 were enrolled in the study. An equally numbered age-matched control group (age 47.1±11.4 years, EDSS 2.5–4.5) was established from individuals affected by MS without any clinical evidence or selfreported spasticity symptoms. Using an optoelectronic system, kinematic and ST parameters of gait, as well as data on dynamic range of motion (ROM) for hip, knee and ankle joints and muscular activation of rectus femoris, lateral gastrocnemius and tibialis anterior, were acquired. Kinematic data were summarized using the gait variable score (GVS) and the gait profile score (GPS), two measures previously validated for MS by the authors. Statistical analysis was performed using two-way multivariate analyses of variance (MANOVA). Results: MANOVA revealed a significant influence of spasticity on gait kinematics, ST parameters and muscular activation (P<0.001 in all cases). In particular, we observed reduced gait speed (–66%), cadence (–63%), stride length (–58%) and swing phase percentage (–27%) and increased double support (+43%, P<0.001 in all cases) in the spasticity group. GPS was significantly increased (11.9° vs. 7.9°, P<0.001) and flexion-extension ROM in hip and knee joints reduced due to spasticity (33.5° vs. 45.9° and 32.5° vs. 58.7°, P<0.001) while EMG activation of rectus femoris increased (0.64 vs. 0.50 V, P<0.001). Conclusions: The 3D quantitative analysis of gait, through the integration of kinematic, ST and EMG data, supplies a detailed picture of the alterations of the gait patterns induced by spasticity in people with MS. Such data may be useful in verifying the actual transfer of the treatment effectiveness from the symptom to the function in the context of real-life activities