MS Speaks

Meeting Coverage



By John Gever, Deputy Managing Editor, MedPage Today

Note that these studies were published as abstracts and presented at a conference. These data and conclusions should be considered to be preliminary until published in a peer-reviewed journal.

DALLAS -- With impaired walking ability generally considered the number one functional problem for multiple sclerosis (MS) patients, new approaches to assistive devices were described here, ranging from the mechanical to the furry.

In the former category, PhD student Morgan Boes and colleagues at the University of Illinois in Urbana-Champaign (UIUC) have designed a self-contained, pneumatic-powered ankle-foot orthosis (AFO) aimed at boosting a patient's ability to push off while walking or climbing stairs.

In the latter category is Bamse, a 6-year-old boxer dog trained by Cecilie Fjeldstad, PhD, of the Oklahoma Medical Research Foundation in Oklahoma City, to provide both physical and psychological support to moderately disabled MS patients as they walk.

Both researchers described their progress to date with their respective approaches at the joint meeting of the Consortium of Multiple Sclerosis Centers and the Americas Committee for Treatment and Research in Multiple Sclerosis (CMSC-ACTRIMS).

Pneumatic Powered AFO

Boes, who is completing her doctoral studies in the UIUC lab of Robert Motl, PhD, showed her device's design at two CMSC-ACTRIMS poster sessions.

It's powered by bottled CO2 gas worn on a belt, which is connected to an AFO that includes positional and force sensors and a pneumatic actuator that flexes the foot while increasing joint stability and motion control.

The primary goal, Boes explained, is to provide "directional powered assistance during each phase of the gait."

Passive AFOs are already widely available to support the foot and ankle in MS patients and others with weakened lower-extremity muscle function. A common problem in MS is drop foot -- impairment in the strength of ankle-foot flexion, depriving patients of the power needed to move forward while walking.

These devices stabilize the joint and hold the foot in a neutral position, which helps patients with drop foot to walk but cannot provide an actual strength boost.

The UIUC device provides up to 100 lbs per square inch (PSI) of force during three of the four gait stages: initial contact when the foot strikes the ground (stage 1), forward propulsion (stage 3), and leg advancement (stage 4). No power is delivered at the second stage, known as loading response, when the weakened foot is flat on the ground and the walker has not yet begun to push off on it.

Pilot studies with healthy people in the lab have indicated that it should perform more or less as desired, but testing in MS patients has not yet begun. Boes's group is gearing up for a trial with planned enrollment of about 30 patients already using an AFO or for whom it has been recommended. The trial will use the 6-minute walk test as the primary endpoint.

Boes admitted that the prototype's design was somewhat awkward looking (although when this was suggested to her, she laughed and said it was "sleek" relative to an earlier model). But she pointed out that it was constructed from readily available and inexpensive components and the pneumatic system was known to be both robust and safe. She said her group had considered an electromechanical design and decided it would have more minuses than pluses.

Service Dog for Walking Assistance

Fjeldstad reported on an initial trial with Bamse (Norwegian for "stuffed teddy bear," she explained, pronouncing it as "bom-suh") in 36 patients with pronounced walking impairment but who did not currently require an assistive device such as a cane or walker.

She personally trained the animal (already a certified therapy dog) to walk beside a person without pulling ahead or lagging behind, and designed a special harness with a flexible handle. Hence, the patient cannot and should not lean on the dog like a cane.

The intent is similar to that of a guide dog for the blind, Fjeldstad indicated. The person may gain some physical steadying from having a hand on the dog's harness, but the support is primarily psychological in giving the patient more confidence in walking.

In the trial, the 36 patients underwent a total of four timed 25-foot walk (T25W) tests with Bamse -- an unassisted walk followed 3 minutes later with a second walk with Bamse. After a 15-minute rest, each patient then repeated the two T25W tests but in reverse order (assisted followed by unassisted).

The mean unassisted time to complete the 25-foot walks was 9.3 seconds (SD 0.4), well in excess of the 8-second threshold for substantial impairment proposed in a Neurology paper last year by several researchers including Motl.

Bamse's assistance improved the T25W times only a little -- to a mean of 8.7 second (SD 0.3), which was statistically significant at P=0.014 -- but then, the participants had not trained with the dog before and one might expect that the confidence boost would increase with practice.

Fjeldstad said that these results should encourage more research into the use of service animals as an aid to ambulation in MS patients.

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The study by Boes' group was supported by the CMSC Foundation and the National Science Foundation Research Center for Compact and Efficient Fluid Power.

The study by Fjeldstad's group had no external funding.

Authors of both studies declared they had no relevant financial interests.


Primary source: CMSC-ACTRIMS

Source reference: Boes M, et al. "Evaluation of a portable powered ankle-foot orthosis on gait function in persons with multiple sclerosis" CMSC-ACTRIMS 2014.


Source reference:Fjeldstad C, et al. "Does using a service dog help ambulation in MS individuals with gait dysfunction?" CMSC-ACTRIMS 2014; Abstract RH07.