Local and global effects of neck muscle vibration during stabilization of upright standing

Abstract

Neck muscle vibration (NMV) during upright standing is known to induce forward leaning, which has been explained as a global response to the (illusory) perception of a lengthening of the dorsal neck muscles. However, the effects of NMV both at the level of individual joints and on whole-body postural coordination, and its potential modulation by vision, have not yet been analyzed in detail. Eight healthy young adult participants completed a total of ten trials each, with a 10-s period of unperturbed standing followed by a 10-s period of NMV. Participants were instructed to stand ''as still as possible''. This postural task was executed under two visual conditions: eyes open (EO) and eyes closed (EC). Postural responses were measured in terms of center of pressure (CoP) and center of mass (CoM) profiles, and whole-body kinematics. Responses to NMV at the level of individual body segments and joints were assessed by decomposing the time series into linear trends and residual fluctuations. Inter-segmental coordination was analyzed using a decorrelation technique, assessing motor-equivalent stabilization of four task-related variables: CoM position, trunk orientation, as well as head position and orientation. NMV induced a general forward leaning response under both visual conditions, visible in CoP, CoM, segment positions and orientations. Locally, NMV induced a pronounced extension of the atlanto-occipital joint. Residual fluctuations were higher with EC and unaffected by NMV. Coordination analysis showed that stabilization of different body parts was differentially affected by NMV. Head orientation was consistently stabilized across all conditions, with weaker coordination in the EC condition. In contrast, motor-equivalent stabilization of CoM and head position, and trunk orientation was only observed during no-vibration periods. Taken together, our results demonstrate specific effects of vision and proprioception on different aspects of local and global postural control. While perturbed neck proprioception seemed to affect the postural ''set point'' (inducing forward leaning), vision appeared to mainly serve in noise reduction (residual fluctuations) and control of head orientation.

Neck muscle vibration can improve sensorimotor function in patients with neck pain

“…Vibration was applied via a handheld vibration device (Vibrasens; Techno Concept, France) that was already used in previous studies [7]. Neck muscles were vibrated for 30 seconds with a frequency of 100 Hz [5] and a linear displacement of 1 mm of the vibration head.…”

“…More specifically, subjects showed increased body sway displacements toward the side opposite to the vibrated spot [6]. Furthermore, altered postural alignment in the upper cervical spine [7], a shifted perception of the body midline [8,9], and illusory movements have been reported [10]. These vibration-induced impairments are of short duration and depend on the length of application.…”

Postural Reorganization Induced by Torso Cutaneous Covibration

“…The processing of recorded signals from both the motion capture system and force plate was performed using MATLAB (MathWorks). The recorded signals (marker and COP displacements) were low-pass filtered with a zero phase, second-order Butterworth filter with a 10 Hz cutoff frequency because the frequency of body kinematic signals is Ͻ10 Hz during quiet standing (Winter, 1995;Sienko et al, 2010;Verrel et al, 2011). The two positions of each pair of homonymous markers (which were placed symmetrically on the aforementioned body landmarks) were averaged to generate a postural profile represented in the midsagittal plane.…”

“…Another recent study found that dorsal neck muscle vibration induced a posterior leaning of the head whereas all of the other body segments leaned in the anterior direction (Verrel et al, 2011). Thus, a coordinated multisegmental response to torso cu-taneous vibration may be likely.…”

Postural Stability and Visual Verticality Perception of Neck Disturbance of the Middle-aged during Quiet Standing

“…Vibration of dorsal neck muscles stimulates neck proprioceptive inputs [8][9][10] , and changes proprioceptive signals code of body spatial orientation and postural stabilization 11) . An increase in forward leaning was induced by neck muscle vibration during static standing, which has been explained as a response to the perception of the lengthening of the dorsal neck muscles 12) .…”