NASHVILLE, TENNESSEE — However, these associations fall away among patients with more severe disease, according to a new study performed in Australia. The findings could eventually help tailor physical activity interventions.
The research grew out of frustrations with developing interventions focused on strength. “There are many systematic reviews showing stronger and stronger evidence that exercise is beneficial. It does change your walking. It does improve your balance,” said Katrina Williams, PhD, during a presentation of the results at the annual meeting of the Consortium of Multiple Sclerosis Centers.
However, when her group’s intervention studies yielded no statistically significant improvements, she began to search for explanations, and began to suspect heterogeneity among MS patients. Their clinic took all comers, regardless of disability level. “[Our attitude was] we will make it work. We’ll get you actively moving and exercising. But when you break down a lot of those systematic reviews, there’s not a lot of teasing out of disability levels. So, potentially, it is the disability level that might be leading to why some people don’t change or why we’re not getting the statistically significant benefits, because we’re not addressing the individual at their level of disease progression,” said Dr. Williams, who is a senior lecturer in physiotherapy at the University of Queensland, Brisbane, Australia.
“Physiotherapists, we love exercise, we love movement, but we’re a bit unidimensional. It’s some strength training, [or] let’s get on that bike and do cardiovascular. But that may not be enough for individuals who have different symptoms profiles. We’re assuming that the motor profile is the most important, and the one that needs to be addressed in these individuals,” said Dr. Williams.
Focusing on Non-Motor Symptoms
When she searched the literature, she could find little evidence of non-motor symptoms correlating to walking, balance, or even quality of life. To dig deeper, her group studied 220 MS patients in Australia who self-reported symptoms of dizziness, vision problems, fatigue, and spasticity. The population had a mean age of 42 years, and 82% were female. They ranged in disease severity from disease step (DS) 0 to DS 6. The researchers categorized respondents as between DS 0 (mild symptoms that were mostly sensory) to DS 3 (MS interferes with walking) and from DS 4 (early cane use) to DS 6 (requiring bilateral walking support).
Deficits were more commonly reported in the DS 4-6 group than the DS 0-3 group with respect to light touch (88% vs 72%), proprioception (63% vs 41%), fatigue (100% vs 96%), and spasticity (78% vs 69%). There were no significant differences in dizziness, vision, or memory/cognition/emotion.
A linear regression model incorporating sensory worsening, age, social participation, perceived deficit, and spasticity showed an R2 adjusted value of 0.73. However, when they looked only at DS 0-3 patients, the R2 value strengthened to 0.86. Among the DS 4-6 group, the correlation largely disappeared with an R2 value of 0.16. Specifically, there were stronger associations in the DS 0-3 group than the overall group (DS 0-6) between perceived walking deficit and sensory worsening (R2 0.45 vs 0.31), fatigue (0.67 vs 0.05), spasticity (0.47 vs 0.16), and balance (0.8 vs 0.16).
“Most non-motor symptoms do have moderate to weak correlations to walking confidence and walking balance, and quality of life, and the correlations do decline as disability worsens. Those with less disability had more correlations that were stronger, particularly for the walking and balance confidence. So [among those] walking without an aid, there are more non-motor correlations aligned to the actual outcomes. In more disabled, they fell away, so there’s something else going on that we do have to look at,” said Dr. Williams.
She called for other clinicians to explore non-motor symptoms in patients with less disability, and the relationships of those symptoms to gait, balance, and overall MS impact, in the hopes that such observations could improve the tailoring of physiotherapy programs.