Interactions of touch feedback with muscle vibration and galvanic vestibular stimulation in the control of trunk posture

Abstract

This study investigated the effect of touch on trunk sway in a seated position. Two touch conditions were included: touching an object with the index finger of the right hand (hand-touch) and maintaining contact with an object at the level of the spine of T10 on the mid back (back-touch). In both touch conditions, the exerted force stayed below 2N. Furthermore, the interaction of touch with paraspinal muscle vibration and galvanic vestibular stimulation (GVS) was studied. Thirteen healthy subjects with no history of low-back pain participated in this study. Subjects sat on a stool and trunk sway was measured with a motion capture system tracking a cluster marker on the trunk. Subjects performed a total of 12 trials of 60-s duration in a randomized order, combining the experimental conditions of no-touch, hand-touch or back-touch with no sensory perturbation, paraspinal muscle vibration or GVS. The results showed that touch through hand or back decreased trunk sway and decreased the effects of muscle vibration and GVS. GVS led to a large increase in sway whereas the effect of muscle vibration was only observed as an increase of drift and not of sway. In the current experimental set-up, the stabilizing effect of touch was strong enough to mask any effects of perturbations of vestibular and paraspinal muscle spindle afference. In conclusion, tactile information, whenever available, seems to play a dominant role in seated postural sway and therefore has important implications for studying trunk control.

Effects of support surface stability on feedback control of trunk posture

“…When vision was occluded in the stable condition, ML trunk acceleration did not significantly increase. Similarly, Maaswinkel et al (2014) did not find an effect of closing the eyes on anteroposterior trunk sway in stable sitting. These findings contrast with effects of closing the eyes on postural sway observed in many previous studies (for an overview see Mazaheri et al 2013).…”

“…Subjects were instructed to look straight ahead and not at their arm. Touching a stationary surface reduces trunk sway (Maaswinkel et al 2014), and it has been shown that whole body sway is coupled to the rhythm of moving surfaces when these are touched (Jeka et al 1998;Wing et al 2011).…”

“…The human ligamentous spine, devoid of muscular control, is incapable of carrying the weight of the upper body, as the smallest perturbation will cause it to buckle (Crisco and Panjabi 1992). Therefore, in addition to passive structures such as the intervertebral discs and the ligaments, back and abdominal muscles contribute to stabilization of the trunk against perturbations (Panjabi 1992) through modulation of co-activation and the resultant muscle stiffness and damping (Cholewicki et al 1997;van Dieen et al 2003) and under feedback control based on the sensory information provided by visual, vestibular, proprioceptive, and tactile afferents (Goodworth and Peterka 2009;Maaswinkel et al 2014). The postural control system appears to use multiple sources of sensory information on trunk movement for feedback control.…”

“…The somatosensory system likewise provides indirect information through sensing of shear or pressure induced by motion between body and support area (Lestienne and Gurfinkel 1988;Massion 1992). Also, in studies of whole body control (Lackner et al 2000) and of trunk control (Maaswinkel et al 2014) it was shown that tactile information contributes. Proprioceptive information appears to be a more direct source of information on trunk movement and probably the only Abstract This study aimed to examine the interactions of visual, vestibular, proprioceptive, and tactile sensory manipulations and sitting on either a stable or an unstable surface on mediolateral (ML) trunk sway.…”

Trunk stabilization during sagittal pelvic tilt: from trunk-on-pelvis to trunk-in-space due to vestibular and visual feedback

“…In addition, galvanic vestibular stimuli in both standing and seated subjects resulted in lateral low-back flexion/extension (Andreopoulou et al 2015;Day et al 1997;Maaswinkel et al 2014). However, pelvic translations in the sagittal plane lead primarily to trunk-on-pelvis stabilization with eyes closed (van Drunen et al 2015), suggesting only minor vestibular contributions to trunk stabilization in the sagittal plane.…”