Effect of Social Context on Cognitive and Motor Behavior: A Systematic Review.

Human cognitive and motor behavior is influenced by the social contexts. The aim of this systematic review is to investigate the impact of the social contexts on human behaviors. A systematic search of the literature was performed via Pub-Med/Medline, Web of sciences, Google scholar, Science direct, Springer-Link and EMBASE and 68 articles were selected. After applying all the inclusion and exclusion criteria, 16 articles were retained. The results show that the presence of other people and the social context influence motor behavior (i.e. movement duration, trajectory behavior, maximum speed) and cognitive behavior (reaction time). Studies have shown an improvement in performance in the presence of other people compared to the individual situation. However, other studies showed that the presence of other people led to deterioration in performance compared to the individual situation. The improvement of behavior is attributed to the social phenomenon of facilitation while the deterioration was explained by the conduct theory or the distraction conflict theory. These social phenomena of facilitation or inhibition could be related to the perception-action theory, which interferes with interaction with other. This, in turn, seems to be associated with neural circuits of mirror neurons and motor system.

How Does the Central Nervous System Control Forthcoming Movement with Different Emotional Stimuli?

Maintaining postural balance is a key factor in human motor skills, based in part on emotional stimuli. Our objective in this study was to measure the effect of emotion on postural control as influenced by the direction of forthcoming movement. Eighteen right-handed women initiated a step forward or backward or remained in a static position after visualizing an emotional stimulus (positive, negative, or neutral). Center of pressure (COP) parameters (2D velocity, Medio-lateral (ML), and antero-posterior (AP) amplitude) were recorded for 3-second windows for movement direction and emotional stimulus. We observed a motion * direction effect on 2D velocity, characterized by a decrease in the emotional stimulus and static direction windows. The participants' ML amplitude was influenced by direction, and their reduced amplitude was evident in the presence of emotions. AP amplitude was high in the direction versus emotion window. In the static position, the AP amplitude was high in the direction window and low in the emotion window. The participants' movement planning and programming phase (direction window) was characterized by less oscillation for forward or backward movements and more oscillation before movement, suggesting anticipatory postural adjustments in the emotion window. Static direction was characterized by low oscillation, compared to forward and backward movement and in negative versus positive emotional context, proving the interactive impact of direction and emotion on COP amplitudes. Thus, postural control was influenced by both movement (direction) and emotional content (valence). This study provided insight regarding the interactive effect of emotion and direction on planning and programming forthcoming movement.

Perception of Emotion and Postural Stability Control at Different Distances.

The effect of emotion on postural control has been widely demonstrated in the literature. Postural control also depends on the distance that separates the subject from the observed stimulus. This work examines (i) the effect of distance on the perception of emotional stimuli and (ii) its effect on postural control. Sixty-eight women were asked to maintain orthostatic equilibrium under three emotional conditions (positive, negative, and neutral) at four distances (0.5 m, 2.1 m, 6 m, and 10 m). The findings showed that the perception of emotions was not influenced by distance but was influenced by valence and intensity, and that postural control was not influenced by emotional valence but by distance, with reduced oscillation amplitudes at 0.5 m distance. The perception of the image (valence and intensity) depended on the content, but not on the distance, and the presentation of emotional images tended to activate the defensive system, regardless of the emotional content. The center of pressure sway amplitude increased with an eye-object distance of up to 6 m (role of vision). The perception of the emotional effect was not linked to the distance effect on the postural control of women in static positions.

Predicting manual wheelchair initiation movement with EMG activity during over ground propulsion.

Context/Objective: This is a preliminary study of movement finalities prediction in manual wheelchairs (MWCs) from electromyography (EMG) data. MWC users suffer from musculoskeletal disorders and need assistance while moving. The purpose of this work is to predict the direction and speed of movement in MWCs from EMG data prior to movement initiation. This prediction could be used by MWC to assist users in their displacement by doing a smart electrical assistance based on displacement prediction.Design: Experimental study.Setting: Trained Subject LAMIH Laboratory.Participants: Eight healthy subjects trained to move in manual wheelchairs.Interventions: Subjects initiated the movement in three directions (front, right and left) and with two speeds (maximum speed and spontaneous speed) from two hand positions (on the thighs or on the handrim). A total of 96 movements was studied. Activation of 14 muscles was recorded bilaterally at the deltoid anterior, deltoid posterior, biceps brachii, pectoralis major, rectus abdominis, obliquus externus and erector spinae.Outcome Measures: Prior amplitude, prior time and anticipatory postural adjustments were measured. A hierarchical multi-class classification using logistic regression was used to create a cascade of prediction models. We performed a stepwise (forward-backward) selection of variables using the Bayesian information criterion. Percentages of well-classified movements have been measured through the means of a cross-validation.Results: Prediction is possible using the EMG parameters and allows to discriminate the direction / speed combination with 95% correct classification on the 6 possible classes (3 directions * 2 speeds).Conclusion: Action planning in the static position showed significant adaptability to the forthcoming parameters displacement. The percentages of prediction presented in this work make it possible to envision an intuitive assistance to the initiation of the MWC displacement adapted to the user's intentions.

Arm-trunk coordination in wheelchair initiation displacement: A study of anticipatory and compensatory postural adjustments during different speeds and directions of propulsion.

Arm-trunk coordination during the initiation of displacement in manual wheelchair is a complex task. The objective of this work is to study the arm-trunk coordination by measuring anticipatory and compensatory postural adjustments. Nine healthy subjects participated in the study after being trained in manual wheelchair. They were asked to initiate a displacement in manual wheelchair in three directions (forward vs. left vs. right), with two speeds (spontaneous vs. maximum) and with two initial hand's positions (hands on thighs vs. hands on handrails). Muscular activities in the trunk (postural component) and the arms (focal component) were recorded bilaterally. The results show two strategies for trunk control: An anticipatory adjustment strategy and a compensatory adjustment strategy with a dominance of compensation. These two strategies are influenced by the finalities of displacement in terms of speed and direction depending on the hands positions. Arm-trunk coordination is characterized by an adaptability of anticipatory and compensatory postural adjustments. The study of this type of coordination for subjects with different levels of spinal cord injury could be used to predict the forthcoming displacement and thus assist the user in a complex task.

Adaptability and Prediction of Anticipatory Muscular Activity Parameters to Different Movements in the Sitting Position.

Voluntary movement often causes postural perturbation that requires an anticipatory postural adjustment to minimize perturbation and increase the efficiency and coordination during execution. This systematic review focuses specifically on the relationship between the parameters of anticipatory muscular activities and movement finality in sitting position among adults, to study the adaptability and predictability of anticipatory muscular activities parameters to different movements and conditions in sitting position in adults. A systematic literature search was performed using PubMed, Science Direct, Web of Science, Springer-Link, Engineering Village, and EbscoHost. Inclusion and exclusion criteria were applied to retain the most rigorous and specific studies, yielding 76 articles, Seventeen articles were excluded at first reading, and after the application of inclusion and exclusion criteria, 23 were retained. In a sitting position, central nervous system activity precedes movement by diverse anticipatory muscular activities and shows the ability to adapt anticipatory muscular activity parameters to the movement direction, postural stability, or charge weight. In addition, these parameters could be adapted to the speed of execution, as found for the standing position. Parameters of anticipatory muscular activities (duration, order, and amplitude of muscle contractions constituting the anticipatory muscular activity) could be used as a predictive indicator of forthcoming movement. In addition, this systematic review may improve methodology in empirical studies and assistive technology for people with disabilities.