  Older adults and people suffering from neurodegenerative disease often
experience difficulty controlling gait during locomotion, ultimately increasing
their risk of falling. To combat these effects, researchers and clinicians have
used metronomes as assistive devices to improve movement timing in hopes of
reducing their risk of falling. Historically, researchers in this area have
relied on metronomes with isochronous interbeat intervals, which may be
problematic because normal healthy gait varies considerably from one step to
the next. More recently, researchers have advocated the use of irregular
metronomes embedded with statistical properties found in healthy populations.
In this paper, we explore the effect of both regular and irregular metronomes
on many statistical properties of interstride intervals. Furthermore, we
investigate how these properties react to mechanical perturbation in the form
of a halted treadmill belt while walking. Our results demonstrate that
metronomes that are either isochronous or random metronome break down the
inherent structure of healthy gait. Metronomes with statistical properties
similar to healthy gait seem to preserve those properties, despite a strong
mechanical perturbation. We discuss the future development of this work in the
context of networked augmented reality metronome devices.
