Locomotor Sensory Organization Test: How Sensory Conflict Affects the Temporal Structure of Sway Variability During Gait

Abstract

When maintaining postural stability temporally under increased sensory conflict, a more rigid response is used where the available degrees of freedom are essentially frozen. The current study investigated if such a strategy is also utilized during more dynamic situations of postural control as is the case with walking. This study attempted to answer this question by using the Locomotor Sensory Organization Test (LSOT). This apparatus incorporates SOT inspired perturbations of the visual and the somatosensory system. Ten healthy young adults performed the six conditions of the traditional SOT and the corresponding six conditions on the LSOT. The temporal structure of sway variability was evaluated from all conditions. The results showed that in the anterior posterior direction somatosensory input is crucial for postural control for both walking and standing; visual input also had an effect but was not as prominent as the somatosensory input. In the medial lateral direction and with respect to walking, visual input has a much larger effect than somatosensory input. This is possibly due to the added contributions by peripheral vision during walking; in standing such contributions may not be as significant for postural control. In sum, as sensory conflict increases more rigid and regular sway patterns are found during standing confirming the previous results presented in the literature, however the opposite was the case with walking where more exploratory and adaptive movement patterns are present.

Mastoid Vibration Affects Dynamic Postural Control During Gait

“…Our previous research with the LSOT has shown that dynamic balance control during walking in healthy individuals is affected by the manipulation of multisensory inputs. 12,13 The amount of sway variability observed during walking reflects similar balance performance with standing posture, indicating that similar feedback processes may be involved. 12 However, the contribution of visual input is significantly increased during walking in comparison to standing.…”

“…Sway variability measures were used as previously described to investigate dynamic postural control. 12,13 We hypothesized that the MV would affect both the amount and the temporal structure of sway variability during walking and, when applied in combination with manipulations of the visual and the somatosensory inputs, would further augment the observations from in our previous work. 12,13 …”

“…Recently, our group has developed the Locomotor Sensory Organization Test (LSOT) 12,13 as a parallel to the SOT. The LSOT uses sequential manipulations of different sensory systems to study the effects of sensory inputs on dynamic postural control during walking.…”

“…Our results with respect to the temporal structure of sway variability also revealed that as sensory conflict increases, more rigid and regular sway patterns are found during standing. 13 The opposite is the case with walking where more exploratory and adaptive movement patterns are present. In our previous studies, 12,13 however, vestibular inputs were not systematically manipulated.…”

“…13 The opposite is the case with walking where more exploratory and adaptive movement patterns are present. In our previous studies, 12,13 however, vestibular inputs were not systematically manipulated. Thus, the effects of vestibular sensory inputs on dynamic postural control during walking remain unknown.…”