Submovement interpersonal coupling is associated to audio-motor coordination performance.

Acting in concert with others, a key aspect of our social life, requires behavioral coordination between persons on multiple timescales. When zooming in on the kinematic properties of movements, it appears that small speed fluctuations, called submovements, are embedded within otherwise smooth end-point trajectories. Submovements, by occurring at a faster timescale than that of movements, offer a novel window upon the functional relationship between distinct motor timescales. In this regard, it has previously been shown that when partners visually synchronize their movements, they also coordinate the timing of their submovement by following an alternated pattern. However, it remains unclear whether the mechanisms behind submovement coordination are domain-general or specific to the visual modality, and whether they have relevance for interpersonal coordination also at the scale of whole movements. In a series of solo and dyadic tasks, we show that submovements are also present and coordinated across partners when sensorimotor interactions are mediated by auditory feedback only. Importantly, the accuracy of task-instructed interpersonal coordination at the movement level correlates with the strength of submovement coordination. These results demonstrate that submovement coordination is a potentially fundamental mechanism that participates in interpersonal motor coordination regardless of the sensory domain mediating the interaction.

The microstructure of intra- and interpersonal coordination.

Movements are naturally composed of submovements, i.e. recurrent speed pulses (2-3 Hz), possibly reflecting intermittent feedback-based motor adjustments. In visuomotor (unimanual) synchronization tasks, partners alternate submovements over time, indicating mutual coregulation. However, it is unclear whether submovement coordination is organized differently between and within individuals. Indeed, different types of information may be variably exploited for intrapersonal and interpersonal coordination. Participants performed a series of bimanual tasks alone or in pairs, with or without visual feedback (solo task only). We analysed the relative timing of submovements between their own hands or between their own hands and those of their partner. Distinct coordinative structures emerged at the submovement level depending on the relevance of visual feedback. Specifically, the relative timing of submovements (between partners/effectors) shifts from alternation to simultaneity and a mixture of both when coordination is achieved using vision (interpersonal), proprioception/efference-copy only (intrapersonal, without vision) or all information sources (intrapersonal, with vision), respectively. These results suggest that submovement coordination represents a behavioural proxy for the adaptive weighting of different sources of information within action-perception loops. In sum, the microstructure of movement reveals common principles governing the dynamics of sensorimotor control to achieve both intra- and interpersonal coordination.

Interpersonal sensorimotor communication shapes intrapersonal coordination in a musical ensemble.

Social behaviors rely on the coordination of multiple effectors within one's own body as well as between the interacting bodies. However, little is known about how coupling at the interpersonal level impacts coordination among body parts at the intrapersonal level, especially in ecological, complex, situations. Here, we perturbed interpersonal sensorimotor communication in violin players of an orchestra and investigated how this impacted musicians' intrapersonal movements coordination. More precisely, first section violinists were asked to turn their back to the conductor and to face the second section of violinists, who still faced the conductor. Motion capture of head and bow kinematics showed that altering the usual interpersonal coupling scheme increased intrapersonal coordination. Our perturbation also induced smaller yet more complex head movements, which spanned multiple, faster timescales that closely matched the metrical levels of the musical score. Importantly, perturbation differentially increased intrapersonal coordination across these timescales. We interpret this behavioral shift as a sensorimotor strategy that exploits periodical movements to effectively tune sensory processing in time and allows coping with the disruption in the interpersonal coupling scheme. As such, head movements, which are usually deemed to fulfill communicative functions, may possibly be adapted to help regulate own performance in time.

[Management of testicular torsion by a general surgeon isolated in Africa]. / Prise en charge de la torsion du testicule par un chirurgien généraliste isolé en Afrique.

The onset of sudden and intense scrotal pain exposes to several problems when it occurs in a young man in Africa. Among the possible etiologies, testicular torsion is the surgical emergency to rule out, because beyond 6 hours of evolution the functional prognosis of the testicle is concerned. The septic evolution towards a purulent melting, in case of exceeded torsion, is also possible. Of slightly lower incidence than in Western countries, lack of awareness of this pathology by local health actors, the precariousness or health isolation of certain populations in certain under-medicalized regions, contribute to diagnostic and therapeutic delays. This often leads to a pejorative development, loss of the testicle being directly correlated with the delay in treatment. Testicular torsion has thus been identified as one of the main causes of male infertility in Africa. However, clinical diagnosis and surgical treatment require few resources and remain accessible in an environment with low resources or in precarious conditions. Indeed, despite the contribution of ultrasound in certain situations, the clinical picture is at the center of the diagnosis and therapeutic decision making. At the slightest doubt, surgical exploration is necessary. The multi-tunic anatomy of the testicle facilitates its surgical fixation in the event of conservation, ideally by triangulation of single-strand non-absorbable thread. Simultaneous fixation of the contralateral testicle is currently the subject of debate in the literature. In Africa, the benefit/risk balance, taking into account in particular the difficulty of subsequent access to care, justifies, from our point of view, performing contralateral orchidopexy at the same time. Depending on the appearance of the testicle and, to a lesser extent, the duration of the evolution of the symptoms, orchidectomy may be necessary. This article describes the clinical picture of spermatic cord torsion and the orchidopexy technique.

Interpersonal synchronization of movement intermittency.

Most animal species group together and coordinate their behavior in quite sophisticated manners for mating, hunting, or defense purposes. In humans, coordination at a macroscopic level (the pacing of movements) is evident both in daily life (e.g., walking) and skilled (e.g., music and dance) behaviors. By examining the fine structure of movement, we here show that interpersonal coordination is established also at a microscopic - submovement - level. Natural movements appear as marked by recurrent (2-3 Hz) speed breaks, i.e., submovements, that are traditionally considered the result of intermittency in (visuo)motor feedback-based control. In a series of interpersonal coordination tasks, we show that submovements produced by interacting partners are not independent but alternate tightly over time, reflecting online mutual adaptation. These findings unveil a potential core mechanism for behavioral coordination that is based on between-persons synchronization of the intrinsic dynamics of action-perception cycles.

Dance Improves Motor, Cognitive, and Social Skills in Children With Developmental Cerebellar Anomalies.

In this multiple single-cases study, we used dance to train sensorimotor synchronization (SMS), motor, and cognitive functions in children with developmental cerebellar anomalies (DCA). DCA are rare dysfunctions of the cerebellum that affect motor and cognitive skills. The cerebellum plays an important role in temporal cognition, including SMS, which is critical for motor and cognitive development. Dancing engages the SMS neuronal circuitry, composed of the cerebellum, the basal ganglia, and the motor cortices. Thus, we hypothesized that dance has a beneficial effect on SMS skills and associated motor and cognitive functions in children with DCA. Seven children (aged 7-11) with DCA participated in a 2-month dance training protocol (3 h/week). A test-retest design protocol with multiple baselines was used to assess children's SMS skills as well as motor, cognitive, and social abilities. SMS skills were impaired in DCA before the training. The training led to improvements in SMS (reduced variability in paced tapping), balance, and executive functioning (cognitive flexibility), as well as in social skills (social cognition). The beneficial effects of the dance training were visible in all participants. Notably, gains were maintained 2 months after the intervention. These effects are likely to be sustained by enhanced activity in SMS brain networks due to the dance training protocol.

[Re]moving Bodies - A Shared Diminished Reality Installation for Exploring Relational Movement.

In this article we explore an epistemic approach we name dis/embodiment and introduce "Articulations," an interdisciplinary project bringing together Virtual Reality (VR) designers, cognitive scientists, dancers, anthropologists, and human-machine interaction specialists. According to Erin Manning, our sense of self and other emerges from processes of bodying and relational movement (becoming oneself by moving in relation with the world). The aim of the project is to exploit the potential of multi-person VR in order to explore the intersubjective dynamics of relational movement and bodying, and to do so with scientific, artistic and therapeutic purposes in mind. To achieve this bridge, we bring up a novel paradigm we name "Shared Diminished Reality". It consists in using minimalist representation to instantiate users' bodies in the virtual space. Instead of using humanoid avatars or full body skeletons, we reduce the representation of the moving bodies to three spheres whose trajectories reflect the tracking of the head and the two wrists. This "diminished"virtual rendition of the body-in-movement, we call dis/embodiment. It provides a simple but clear experience of one's own responsive movement in relation to the world and other bodies. It also allows for subtle manipulations of bodies' perceptual and cross-perceptual feedback and simplifies the tracking and the analysis of movements. After having introduced the epistemic framework, the basic architecture, and the empirical method informing the installation, we present and discuss, as a proof-of-concept, some data collected in a situated experiment at a science-art event. We investigate motion patterns observed in different experimental conditions (in which participants either could or could not see the representation of their own hands in the virtual space) and their relation with subjective reports collected. We conclude with reflection on further possibilities of our installation in exploring bodying and relational movement.

Coordinated Interpersonal Behaviour in Collective Dance Improvisation: The Aesthetics of Kinaesthetic Togetherness.

Collective dance improvisation (e.g., traditional and social dancing, contact improvisation) is a participatory, relational and embodied art form which eschews standard concepts in aesthetics. We present our ongoing research into the mechanisms underlying the lived experience of "togetherness" associated with such practices. Togetherness in collective dance improvisation is kinaesthetic (based on movement and its perception), and so can be simultaneously addressed from the perspective of the performers and the spectators, and be measured. We utilise these multiple levels of description: the first-person, phenomenological level of personal experiences, the third-person description of brain and body activity, and the level of interpersonal dynamics. Here, we describe two of our protocols: a four-person mirror game and a 'rhythm battle' dance improvisation score. Using an interpersonal closeness measure after the practice, we correlate subjective sense of individual/group connectedness and observed levels of in-group temporal synchronization. We propose that kinaesthetic togetherness, or interpersonal resonance, is integral to the aesthetic pleasure of the participants and spectators, and that embodied feeling of togetherness might play a role more generally in aesthetic experience in the performing arts.

Embodiment of intersubjective time: relational dynamics as attractors in the temporal coordination of interpersonal behaviors and experiences.

This paper addresses the issue of "being together," and more specifically the issue of "being together in time." We provide with an integrative framework that is inspired by phenomenology, the enactive approach and dynamical systems theories. To do so, we first define embodiment as a living and lived phenomenon that emerges from agent-world coupling. We then show that embodiment is essentially dynamical and therefore we describe experiential, behavioral and brain dynamics. Both lived temporality and the temporality of the living appear to be complex, multiscale phenomena. Next we discuss embodied dynamics in the context of interpersonal interactions, and briefly review the empirical literature on between-persons temporal coordination. Overall, we propose that being together in time emerges from the relational dynamics of embodied interactions and their flexible co-regulation.

Head to head comparison of nomograms predicting probability of lymph node invasion of prostate cancer in patients undergoing extended pelvic lymph node dissection.

OBJECTIVE: To validate the Briganti nomogram and compare it with 2 current lymph node invasion (LNI) nomograms (the Cagiannos nomogram and the updated 2007 Partin tables). The Briganti nomogram predicts the probability of LNI in patients undergoing extended pelvic lymph node dissection (EPLND) during radical prostatectomy for prostate cancer. METHODS: Irrespective of the risk of LNI, 173 consecutive patients were treated for localized prostate cancer with radical laparoscopic prostatectomy and EPLND. The area under the receiver operating characteristics curve was used to estimate the predictive accuracy of the nomograms, and calibration plots were used for comparisons between the predicted and observed probabilities of LNI. RESULTS: The median number of nodes removed was 15 (range 10-34). Of the 173 patients, 12 (6.9%) had LNI. The Briganti nomogram achieved a receiver operating characteristic curve of 0.88 versus 0.83 with the Cagiannos nomogram and 0.84 with the 2007 Partin tables. The difference in predictive accuracy was not statistically significant (P < .2). The Briganti nomogram showed only minor departures from the ideal predictions in the low-risk range and the Cagiannos nomogram showed major departures from the ideal predictions for the entire risk range. CONCLUSION: The Briganti nomogram provides highly accurate predictions of the risk of LNI after EPLND. Its performance tended to be increased without being significantly better. The other tools also performed reasonably well but underestimate the true risk of LNI. We recommend the use of these tools to identify patients at low risk of LNI for whom EPLND can be safely spared.