1. The Effect of Bilateral Vestibular Stimulation on Locomotor Adaptation
Allison Hoover, Diderick Jan Eikema, Troy Rand, Mukul Mukherjee
University of Nebraska at Omaha, Omaha, Nebraska
INTRODUCTION
RESULTS
The vestibular system is important for maintaining postural control during gait.1
When the vestibular system is perturbed during gait , postural control shows decrements.2
During split belt adaptation, vestibular perturbation through caloric irrigation was shown to affect gait adaptation during slow but not fast walking.3
It is not clear however, how bilateral mastoid vibration would affect split-belt adaptation.
Sensory perturbation is known to enhance adaptive transfer effects through multisensory recalibration.4 such enhanced effects can potentially accelerate rehabilitation in patient populations.
Purpose: Determine if vestibular stimulation will affect gait coordination during learning of a split-belt task.
Figure 2. The Early Adaptation trial showed significant differences from Late Adaptation and Second Exposure trials. * = Significant difference compared to baseline.
METHODS
Group N
Age (years)
Height (cm)
Weight (kg)
Controls 9
21.3 (0.9)
(8.11)
79.79 (16.88)
Received Stimulation
22.3 (3.6)
(11.96)
69.85 (8.64)
Table 1. Means and standard deviations for group characteristics. No significant differences were observed between groups
Figure 1. During Early Adaptation, the group that did not receive stimulation had a greater increase in variability. † = Significant difference from late adaptation, second exposure, and early adaptation with stimulation.
18 subjects (9 receiving vestibular stimulation, 9 healthy controls) walked on a split-belt treadmill, right leg 0.5 m/s faster than the left for three trials. Baseline preferred walking speed trials were also recorded. This baseline trial was then compared to early adaptation split-belt trial, late adaptation split-belt trial, and a second exposure split-belt trials.
DISCUSSION
Bilateral mastoid vibration did not disrupt the learning of the split belt task mechanism.
However those who received the perturbation had a significantly lower variability in the Early Adaptation trial when compared to the Late Adaptation and Second Exposure trials.
The lower variability may indicate a restriction in gait pattern in order to allow sensory organization for learning the split-belt task.
Figure 1. Shows a subject receiving vestibular stimulation while walking on the split-belt treadmill. All subjects had tactors placed on their mastoid processes. 9 received vestibular stimulation from these tactors and 9 were control subjects.
CONCLUSIONS
In healthy subjects, sensory recalibration may reduce the effect of vestibular disruption during gait coordination training.
However, in older adults or those with sensorimotor pathology, such recalibration may be difficult leading to possible risk of falls.
Marker position data was used to determine the difference between step length and stride time for each of the three trials which was calculated and then compared for each group. The stride time for the left and right legs were also compared.
REFERENCES
[1] Chien et al., Sci Rep Jan 27;7:41547.
[2] Chien et al., Ann Biomed Eng Sep;44(9):
[3] Marques et al., Exp Brain Res
[4] Mukherjee et al., Exp Brain Res. Oct;233(10):
ACKNOWLEDGENMENTS: Funding provided by the University of Nebraska Fund for Undergraduate Scholarly Experience (FUSE), and NASA Nebraska Space Grant Fellowship program and COBRE grant from NIH/NIGMS.