Bipedal Hopping Reveals Evidence of Advanced Neuromuscular Aging Among People With Mild Multiple Sclerosis

Abstract

Measures of walking such as the timed 25-ft walk test (T25FWT) may not be able to detect subtle impairment in lower limb function among people with multiple sclerosis (MS). We examined bipedal hopping to determine to what extent people with mild (Expanded Disease Severity Scale ≤ 3.5) MS (n = 13) would differ compared to age-, gender-, and education-matched controls (n = 9) and elderly participants (n = 13; ≥ 70 years old). We estimated lower limb power (e.g., hop length, velocity), consistency (e.g., variability of hop length, time), and symmetry (ratio of left to right foot). Participants completed the T25FWT and, after a rest, they then hopped using both feet 4 times along the walkway. We found that although all groups scored below the 6 -s cutoff for T25FWT, the elderly group had significantly shorter hop lengths, more variability, and more asymmetry than the controls. The results of the MS group were not significantly different from the elderly or controls in most measures and most of their values fell between the control and elderly groups. Hop length, but not measures of walking predicted Expanded Disease Severity Scale score (R = .38, p = .02). Bipedal hopping is a potentially useful measure of lower limb neuromuscular performance.

Bipedal hopping timed to a metronome to detect impairments in anticipatory motor control in people with mild multiple sclerosis

“…Therefore, while the T25FWT was not sensitive enough to detect subtle motor impairment, hopping was able to expose these motor deficits in the same group of individuals. Hopping variables were also predictive of EDSS score (r 2 = 0.38, p = 0.02) (Kirkland et al, 2016). These findings suggest that bipedal hopping may be useful in exposing underlying motor impairment in individuals with low disability scores (Kirkland et al, 2016).…”

“…There has been one study that has measured hopping ability in people with mild MS. This study reported that people with MS display hopping abilities characteristic of an older individual, demonstrating potential early senescence of the neuromuscular system (Kirkland et al, 2016). In this particular study, MS subjects with mild disability as well as age and gender matched controls and elderly subjects performed a two-foot, forward hop at their self-selected pace.…”

“…Hopping variables were also predictive of EDSS score (r 2 = 0.38, p = 0.02) (Kirkland et al, 2016). These findings suggest that bipedal hopping may be useful in exposing underlying motor impairment in individuals with low disability scores (Kirkland et al, 2016). Therefore, in the present study, we utilized bipedal hopping as the motor task for the measure we developed.…”

“…The ability to expose deficits in individuals with MS early in the disease course could help play a pivotal role in targeting therapy and interventions for this group to halt or slow the progression of disability. Previous work has shown that bipedal hopping can detect motor deficits in individuals with MS in the low Expanded Disability Status Scale (EDSS) range (EDSS £ 3.5) (Kirkland et al, 2016). However, not all individuals present with primary motor deficits; some have primarily sensory or cognitive deficits (DeLuca & Nocentini, 2011).…”

“…Several groups are developing more complex motor tasks in order to detect subtle deficits, such as dual-tasking Kirkland, Wallack, Rancourt, & Ploughman, 2015) and standing balance (Spain et al, 2012). Kirkland et al (2016) demonstrated that a bipedal hopping task can reveal motor deficits in a measurable way, even in participants who do not surpass the six-second clinical cut-off of the T25FWT (Kirkland et al, 2016). In the bipedal hop test, PwMS in their 40's demonstrated neuromuscular deficits reminiscent of subjects 30 years their senior (Kirkland et al, 2016).…”