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McLoughlin J.1, Barr C.1, Lord S.2, Sturnieks D.2, Patritti B.3, North R.4, Crotty M.1
1Flinders University, Rehabilitation, Aged & Extended Care, Adelaide, Australia, 2Neuroscience Research Australia (NeuRA), Sydney, Australia, 3Repatriation General Hospital, Adelaide, Australia, 4Orthotics and Prosthetics SA, Adelaide, Australia
Background: Fatigue and difficulty with mobility are major problems for people with Multiple Sclerosis (MS). Walking induced fatigue leads to a reduction in lower limb strength as well as deterioration in standing postural sway in those people with MS with mild to moderate disability. Foot drop is a common problem of walking in people with MS with reduced dorsiflexion at initial contact shown to occur after a fatiguing walk using the six-minute walk test. Increased postural sway, reduced lower limb strength and trips are all known to contribute to falls in people with MS, so any intervention able to minimise these impairments may be of important therapeutic value.
Purpose: The aim of our research was to investigate ways to minimise known effects of walking induced fatigue on a number of key mobility related motor impairments with interventions that assist ankle dorsiflexion. We investigated two orthotic interventions including a Dorsiflexion Assist Orthosis (DAO) and a Functional Electrical Stimulation Device (FES).
Methods: The DAO (Foot-Up®, Ossur) was investigated using a randomised cross-over design involving 34 people with MS, that analysed a number of measures before, during and after a 6MWT including; walking distance fatigue, physiological cost, lower limb strength and postural sway. To investigate FES (NESS L300®, Bioness Inc.,Valencia, CA), Thirteen people with MS completed a timed up and go (TUG), postural sway, lower limb strength 3D gait analysis with FES off and on, before and after a fatiguing 6-minute walk, at baseline and after 8 weeks of FES use.
Results: The use of the DAO was immediately effective in reducing the physiological cost of walking and mitigating the fatigue effects on knee extensor strength and standing postural sway following the 6MWT. Prolonged use of an FES device for foot drop in people with MS over an 8-week period resulted in improved TUG, knee extensor strength and postural sway. Gait changes included improved ankle and knee control after initial contact, an increase in ankle plantarflexion push off power and hip power generation in late stance, with improved parameters of step time, step length, and double support time. 8-weeks of FES alone was not sufficient to overcome all fatigue related deficits in gait following the 6MWT, but there was evidence that it was able to ameliorate some fatigue effects on lower limb kinetics, including benefits to ankle power at push-off.
Conclusion(s): Targeted interventions, such as the DAO, that aim to minimize fatigue related effects may lead to more efficient mobility. Prolonged use of an FES device leads to improved mobility and lower limb strength with resultant improvement in gait parameters, even under fatigued conditions.
Implications: With increasing evidence for gait and balance retraining to manage mobility and fatigue in people with MS, further research should combine these interventions with ankle orthotic devices to determine what additional benefit these might provide in improving safe mobility over longer distances.
Funding acknowledgements: Multiple Sclerosis Research Australia, The Repat Foundation, Australian National Members Society of the International Society for Prosthetics and Orthotics.
Topic: Neurology
Ethics approval: DAO - Repatriation General Hospital Research and Ethics Committee (EC00191). FES - Southern Adelaide Clinical Human Research Ethics Committee (202.10)
All authors, affiliations and abstracts have been published as submitted.
