Treating Foot Drop in People With Multiple Sclerosis Using Electrical Stimulation

People with multiple sclerosis (MS) often suffer from foot drop, which impairs their walking ability. Foot drop is the inability to lift the foot during the swing phase of walking. The purpose of this study is to find out if electrical stimulation of the leg, using the Bioness L300 Foot Drop System, can be used to treat foot drop in people with MS. It is expected that using this system will reduce foot drop, and therefore improve walking ability, particularly in the areas of speed, strength, balance and falls.

Due to damage of their central nervous system, people with multiple sclerosis (MS) often develop abnormal gait. One common problem is the inability to lift the foot during the swing phase; this is called foot drop, and is caused by loss of ankle dorsiflexor strength and spasticity of the ankle plantarflexors. Foot drop leads to imbalance and increased risk of falling, due to the foot dragging on the ground. Treating foot drop can result in improved gait, faster walking speeds, improved balance and reduced risk of falling. Functional electrical stimulation (FES) stimulates either the superficial or deep branches of the common peroneal nerve. This stimulation leads to contraction of the ankle dorsiflexors and evertors, which causes dorsiflexion and eversion of the foot, resulting in the stepping motion of lifting the toes toward the shin. This reduces foot drop, allowing the user to regain a more natural stepping pattern; it also reduces spasticity, strengthens muscles and increases joint range of motion. The Bioness L300 Foot Drop System consists of three components: a leg cuff worn just below the knee, which provides electrical stimulation to the common peroneal nerve; a gait sensor attached to the shoe, which detects which stage of the gait cycle the foot is in; and a control unit, which is used to adjust the level of stimulation received. These three components communicate wirelessly with each other, so that the electrical stimulation is applied at the appropriate time during each gait cycle. The study physician will set up the system to optimize stimulation according to each participant's gait and needs, and participants will use the system for 12 weeks. There will be an initial four week adaptation period for using the system. During this first four weeks participants will gradually increase their use of the system until they are using it all day, which will allow their muscles to adjust to the electrical stimulation and help prevent fatigue. During the remaining eight weeks participants will be instructed to use the system all day, when walking at home and in the community. Participants will have their walking speed and heart rate measured during a 10-metre straight line walking test and a 4-minute figure-8 walking test at baseline, weeks 4, 8 and 12. Participants will perform both tests at each time point without and with the L300 Foot Drop System. Participant satisfaction will be assessed at the end of the 12-week trial.

Participants will use the Bioness L300 Foot Drop System for walking daily during the 12 weeks of the study.

During the 10-metre straight line walking test, participants walk 10 metres, as marked on the floor with tape, at a steady, self-selected pace, with room for acceleration and deceleration before and after the test. The test measures walking speed, which assesses overall gait function and stability. Participants will complete this test both with and without using the L300 device.

During the 4-minute figure-8 walking test, participants walk at a self-selected speed around a figure-8 track as many times as they can during the four-minute test. The test measures speed, balance, stability and coordination, since it incorporates turning.

During the 10-metre straight line walking test, participants walk 10 metres, as marked on the floor with tape, at a steady, self-selected pace, with room for acceleration and deceleration before and after the test. The test measures walking speed, which assesses overall gait function and stability. Participants will complete this test both with and without using the L300 device. This timepoint will assess the initial effects of the L300 device.

During the 10-metre straight line walking test, participants walk 10 metres, as marked on the floor with tape, at a steady, self-selected pace, with room for acceleration and deceleration before and after the test. The test measures walking speed, which assesses overall gait function and stability. Participants will complete this test both with and without using the L300 device.

During the 4-minute figure-8 walking test, participants walk at a self-selected speed around a figure-8 track as many times as they can during the four-minute test. The test measures speed, balance, stability and coordination, since it incorporates turning. This timepoint will assess the initial effects of the L300 device.

During the 4-minute figure-8 walking test, participants walk at a self-selected speed around a figure-8 track as many times as they can during the four-minute test. The test measures speed, balance, stability and coordination, since it incorporates turning.

The satisfaction questionnaire will assess participant satisfaction with the L300 Foot Drop System. It will include information about ease of use and desire to continue using the system.

Participants will walk on a standard treadmill at a slow, comfortable speed between 0.5 to 0.8 m/s for one minute. The treadmill is instrumented with an unobtrusive pressure mapping system (Vista Medical Ltd) under the treadmill belt. The pressure mapping system records the centre of foot pressure for each step, which is used to compute step length and width, step time and swing time for 30 consecutive steps. These spatio-temporal gait variables are used to quantify gait performance. This assessment will be completed at baseline and week 12.

Inclusion Criteria: Have multiple sclerosis for at least one year Being 18 years of age or older Have upper motor neuron-type foot drop (based on the study clinician's medical opinion) Able to ambulate at least 10 metres independently or with one person assistance, with or without walking aid Having the cognitive capacity to understand and follow the study protocol Exclusion Criteria: Severe cardio-respiratory difficulties (including using a pace-maker) or other health issues that may prohibit walking training Significant lower motor neuron neuropathy (based on the study clinician's medical opinion) History of frequent falls (more than once a week) Having used functional electrical stimulation to treat gait within the past six months

Laufer Y, Hausdorff JM, Ring H. Effects of a foot drop neuroprosthesis on functional abilities, social participation, and gait velocity. Am J Phys Med Rehabil. 2009 Jan;88(1):14-20. doi: 10.1097/PHM.0b013e3181911246.

Ring H, Treger I, Gruendlinger L, Hausdorff JM. Neuroprosthesis for footdrop compared with an ankle-foot orthosis: effects on postural control during walking. J Stroke Cerebrovasc Dis. 2009 Jan;18(1):41-7. doi: 10.1016/j.jstrokecerebrovasdis.2008.08.006.

Stein RB, Everaert DG, Thompson AK, Chong SL, Whittaker M, Robertson J, Kuether G. Long-term therapeutic and orthotic effects of a foot drop stimulator on walking performance in progressive and nonprogressive neurological disorders. Neurorehabil Neural Repair. 2010 Feb;24(2):152-67. doi: 10.1177/1545968309347681. Epub 2009 Oct 21.

O'Dell MW, Dunning K, Kluding P, Wu SS, Feld J, Ginosian J, McBride K. Response and prediction of improvement in gait speed from functional electrical stimulation in persons with poststroke drop foot. PM R. 2014 Jul;6(7):587-601; quiz 601. doi: 10.1016/j.pmrj.2014.01.001. Epub 2014 Jan 9. Erratum In: PM R. 2014 Oct;6(10):967.