Gait stability correlates with axonal loss in early MS

Multiple sclerosis

By Mardi Chapman

19 Sep 2022

Gait stability is a more sensitive indicator of neurodegeneration than currently used measures such as walking speed in people with early multiple sclerosis (MS) and low disability scores, an Australian study reports.

The trial compared gait stability in 25 people with MS and 15 healthy controls. MS patients were Expanded Disability Status Scale (EDSS) 0-2 with no evident gait changes on standard clinical examination and a 3D motion capture system was used to record marker kinematics in participants walking for 5 mins on a treadmill at a fixed walking speed.

Data included step time, step width, stride time, cadence and local divergence exponents (LDE) which were calculated across multiple planes as a measure of gait stability.

Participants also had whole-body scans using ultra-high field 7-Tesla MRI, 3D T1-weighted structural scans of the brain and DWI tractography.

The study, published in the Multiple Sclerosis Journal (link), found that people with MS had higher LDEs or lower stability than healthy controls.

As well, lower gait stability was associated with greater tract damage in MS patients.

“We found that of all tract measures, CSTFDC [a combined measure of fibre density and fibre cross-section in the corticospinal tract] was the main predictor (significant) of gait stability when measured at both sacral and cervical levels.”

“These findings highlight the importance of the CST integrity to maintain the functionality of gait, particularly stability.”

The study found LDE at the 7th cervical vertebra was also moderately correlated with mean fibre density and the combined FDC at the interhemispheric sensorimotor tracts (IHSTs).

“Damage to the IHST has been shown to correlate with decreased functionality of the trans-callosal inhibitory sensorimotor network, which may affect bilateral synchronisation of motor outputs during walking.”

The investigators, led by LaTrobe University’s Research Fellow in Sport and Exercise Science Dr Eduardo Cofre Lizama, said the findings were relevant for better understanding the underlying structural damage which may explain deterioration in gait stability in people with MS.

“Some studies have already shown the sensitivity of LDE to physiotherapy interventions and sensory manipulations in people with MS. It is possible that LDE, or perhaps other non-linear measures of gait, may also be sensitive to the effects of newly developed disease-modifying drugs,” the investigators said.

They concluded ongoing longitudinal studies would provide evidence for the potential use of the LDE as a more sensitive measure of walking deterioration in MS.

“Furthermore, implementation of the LDE in clinical settings using wearable technology may help to routinely monitor progress and effects of pharmacological and non-pharmacological interventions at early stages of the disease for more timely clinical decision-making.”

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