Long-Lasting Event-Related Beta Synchronizations of Electroencephalographic Activity in Response to Support-Surface Perturbations During Upright Stance: A Pilot Study Associating Beta Rebound and Active Monitoring in the Intermittent Postural Control

Movement related beta band cortical oscillations, including beta rebound after execution and/or suppression of movement, have drawn attention in upper extremity motor control literature. However, fewer studies focused on beta band oscillations during postural control in upright stance. In this preliminary study, we examined beta rebound and other components of electroencephalogram (EEG) activity during perturbed upright stance to investigate supraspinal contributions to postural stabilization. Particularly, we aimed to clarify the timing and duration of beta rebound within a non-sustained, but long-lasting postural recovery process that occurs more slowly compared to upper extremities. To this end, EEG signals were acquired from nine healthy young adults in response to a brief support-surface perturbation, together with the center of pressure, the center of mass and electromyogram (EMG) activities of ankle muscles. Event-related potentials (ERPs) and event-related spectral perturbations were computed from EEG data using the perturbation-onset as a triggering event. After short-latency (<0.3 s) ERPs, our results showed a decrease in high-beta band oscillations (event-related desynchronization), which was followed by a significant increase (event-related synchronization) in the same band, as well as a decrease in theta band oscillations. Unlike during upper extremity motor tasks, the beta rebound in this case was initiated before the postural recovery was completed, and sustained for as long as 3 s with small EMG responses for the first half period, followed by no excessive EMG activities for the second half period. We speculate that those novel characteristics of beta rebound might be caused by slow postural dynamics along a stable manifold of the unstable saddle-type upright equilibrium of the postural control system without active feedback control, but with active monitoring of the postural state, in the framework of the intermittent control.

Cortical Activity During Postural Recovery in Response to Predictable and Unpredictable Perturbations in Healthy Young and Older Adults: A Quantitative EEG Assessment

Introduction: To investigate the effects of predictable and unpredictable external perturbations on cortical activity in healthy young and older adults. Methods: Twenty healthy older and 19 healthy young adults were exposed to predictable and unpredictable external perturbations, and their cortical activity upon postural recovery was measured using a 32-channel quantitative encephalography. The absolute spectral power and coherence z-scores of cortical waves were analyzed through a 3-way mixed ANOVA. Results: During postural recovery from predictable perturbations, older adults exhibited higher frontoparietal beta power and higher alpha and beta coherence during the late-phase recovery than the young individuals. After unpredictable perturbations, the older group showed lower alpha power in the early phase and higher beta power in the late phase as compared to the young group. Results for the group × time and group × location interactions in the older group showed a higher alpha and beta coherence over the late phase, a higher alpha coherence in F3−P3 and F4−P4 regions, and a higher beta coherence in the F4−P4 region compared to the younger group. Conclusion: Our results revealed that the cortical activation after external perturbations increases with aging, particularly in frontoparietal areas. A shift from automatic (subcortical level) to attentional (cortical level) processing may reflect the contribution of attentional resources for postural recovery from an external threat in older individuals.

The Feasibility of Using the Virtual Time-to-Contact Measure of Postural Stability to Examine Postural Recovery in People With Diabetes Mellitus

This study aimed to examine the feasibility of using time-to-contact measures during the perturbation protocol in people with diabetes mellitus. Three-dimension motion capture and force data were collected during 0.5-s perturbations in four directions (forward, backward, right, and left) and at two accelerations (20 and 40 cm/s2) to compute the time-to-contact. Time-to-contact analysis was divided into three phases: perturbation, initial recovery, and final recovery. The statistical analysis showed the main effects of Direction and Phase (p < .01) as well as a Direction by Phase interaction (p < .01). Backward perturbation with lower acceleration and backward/forward perturbation with higher acceleration had deleterious effects on postural stability in people with diabetes mellitus.

Long-lasting event-related beta synchronizations of electroencephalographic activity in response to support-surface perturbations during upright stance

Movement related beta band cortical oscillations, including beta rebound after execution and/or suppression of movement, have drawn attention in upper extremity motor control literature. However, fewer study focused on beta band oscillations during postural control in upright stance. Here, we examined beta rebound and other components of electroencephalogram (EEG) activity during perturbed upright stance to investigate supraspinal contributions to postural stabilization. Particularly, we aimed to clarify the timing and duration of beta rebound within a non-sustained, but long-lasting, postural recovery process that occurs more slowly compared to upper extremities. To this end, EEG signals were acquired from nine healthy young adults in response to a support-surface perturbation, together with the center of pressure (CoP) and mass (CoM) and electromyogram (EMG) activities of ankle muscles. Event-related potentials (ERPs) and event-related spectral perturbations were computed from EEG data using the perturbation-onset as a triggering event. After short-latency (< 0.3 s) ERPs, our results showed high-beta band power decrease (event-related desynchronization), which was followed by an event-related synchronization at high-beta band and theta band desynchronization. Specifically, beta synchronization (beta rebound) was sustained for as long as three seconds. EMGs of the ankle muscles and the ankle and hip joint torques remained activated in the first half period of the beta rebound. They returned to the steady-state in the remaining phase, where the CoP/CoM were in their final approach to the equilibrium. We propose possible mechanistic causes of the long-lasting beta rebound, which may be related to underlying intermittent control strategy in upright stance.New & NoteworthyBeta rebound cortical activity was identified during postural recovery from a perturbed upright stance. Contrary to upper extremities, it was initiated before the recovery of motion was completed, and sustained for as long as three seconds. Those novel characteristics of the beta rebound might be caused by slow dynamics of the upright posture and by selections of on/off switching in an intermittent feedback controller, which was shown to stabilize upright posture.

PROPHYLAXIS CAUSED BY OVERLOADING THE JUNIOR JUDO PLAYER

The research was conducted on judo performance, from the National Romanian Olympic Junior Judo Centre from Pitesti. In the first phase subjects we discussed and insisted on postural defects awareness and adoption of hypercorrection posts. In the second phase begins corrective physical therapy programs, aimed at toning the muscles of the back and seat scapula-humeral and pelvic muscle tone and movement promoting linkages within. In the first category 14 athletes have incorrect postural attitudes to an improvement in their clinical symptoms. For the other four programs should continue for months or years to obtain the necessary correction. 90% of subjects studied had attitudes among kyphotic, kyphoscoliosis, scoliosis, and inadequacies kyphosis and scoliosis. By implementing physical therapy programs we followed the following objectives: enhancing the mobility of the spine; Postural recovery; Selective muscle tone back and abdomen; paravertebral muscles change length selection; improving respiratory function; general training body.