World MS Day – research into fall risk in multiple sclerosis

Today is World MS Day. Currently approximately 20,000 people in Australia live with Multiple Sclerosis. The international theme this year is ‘independence’ with MS organisations all over the world celebrating ways that people affected by MS can maintain independence and get on with their lives. At NeuRA, Dr Phu Hoang and colleagues are investigating how research into reducing falls in those affected by MS can assist with promoting that independence.

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Dr Phu Hoang

Falls are highly prevalent among people with multiple sclerosis (MS). Research on falls in MS in the past 5 years consistently showed that about 60% of people with MS will experience at least one fall in the next 3 – 6 months and more than 30% people with MS will experience 3 or more falls (these people are often referred as “frequent fallers”). Nearly 50% of MS fallers will sustain a fall-related injury, sometimes very complicated that can keep the person with MS in hospital for months. But, more importantly, the fear of falls that developed from bad experience with falls are also very high among people with MS, which, in turn, can severely affect the confidence of people with MS in their physical activities in daily living. It has been shown that increased concern about falling associates with MS severity, which is primarily mediated by reduced physical ability (especially if this resulted in disability and falls) and less so by executive functioning. This suggests people with MS have a realistic appraisal of their concern about falling.

The risks of falling in MS are multifactorial. Many of the signs and symptoms typical of MS, such as poor balance, muscle weakness, visual impairments, altered sensation and impaired thinking can contribute to fall risks. To date our understanding of which combinations of symptoms pose the greatest risk of falls is much better than 5 years ago. A number of research groups in the world recently focused on studies to investigate the key risk factors for falls in people with MS and develop targeted interventions to reduce falls. In general, the profile of an MS “frequent faller” includes high disability levels, progressive course of the disease, use of ambulation device, poor performance in walking, coordination and balance tests and reduced cognitive capacity. On the other hand, gender and age seem to not have any influence on frequency of falls.

The next questions for both clinicians and researchers are perhaps how to best measure fall risks in people with MS and what tests can be used in clinical trials to test the effectiveness of falls intervention programs. The recently formed International MS Falls Prevention Research Network (IMSFPRN) suggests that the primary outcome measure of a falls-prevention program should be a reduction in the number of falls, and that fall risk measures of dynamic balance be included as an outcome measure for use in falls-prevention trials.

Measures of dynamic balance in MS are often either done with “high-tech” equipment in the laboratories such as posturography using force plate or with “low-tech” equipment in clinical setting. We have recently tested a very simple tool called the Choice Stepping Reaction Time (CSRT) test for measuring falls risk in people with MS. This ‘low-tech’ method uses a rubber mat and a stopwatch to measure the time it takes to complete 20 steps onto four targets on the mat. The CSRT test did indeed show that this “simple and low-tech” equipment can be used to accurately predict falls risk in people with MS and that it can also discriminate between those who are frequent or non-frequent fallers.

Another “low-tech” tool that can be used to measure fall risks in MS in clinical settings is PPA or “Physiological Profile Assessment” tool that was originally designed by NeuRA’s Prof Stephen Lord for identifying the profile of falls risk factors in elderly individuals. The tool measures lower limb strength, proprioception in the lower limb, balance, vision, hand reaction time and mental information processing speed. The tool is now used around the world to assess falls risk in the elderly. In a recent study published in the Multiple Sclerosis Journal – Experimental, Translational and Clinical, we successfully showed that the PPA can also be accurately used to test and predict falls risk in people with MS. We evaluated the PPA in a group of 416 people with MS and compared them to 352 age matched people without MS. The results showed that the PPA can not only accurately distinguish between people with MS who are ‘non fallers’ and those who are ‘fallers’ but also to differentiate people with MS who were frequent fallers and non-frequent fallers.

In addition, this study also shows that falls risk in people with MS is driven by different factors than those seen in ageing. While sensing lower limb position and lower limb strength are important risk factors for falls in the elderly, visual contrast sensitivity, reaction time and postural sway are, on average, stronger risk factors for falls in people with MS. Together, the above studies show that the low-tech CSRT and PPA can be used clinically to measure dynamic balance to identify people with MS who are at increased risk of falls, and will also be invaluable in in clinical trials of falls intervention programs to ensure that fall reduction programs work and are beneficial in managing falls risk in people with MS. The next step is to establish the reliability of these tests in MS.

Regarding interventions to reduced falls in MS, we have already pilot-tested a home-based step-training program aiming to improve balance in people with MS. The study showed that the home-based stepping exercises not only could improve balance and reaction time in people with MS but also had positive impact on cognitive processing capacity in people with MS. In the past 12 months, with a grant from the NHMRC, we were able to develop a much better step training system compared with the original one. We are poised to roll out a full-scale clinical trial using the new step training system to test whether it is effective in reducing falls in people with MS.

 

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