An exploratory study of the kinematics of girls with Turner Syndrome in a visuo‐motor task

In this paper a study is reported in which a group of children with Turner Syndrome (TS) is compared on motor performance tests and real‐time kinematic data with a control group. The objective of this study was to identify possible kinematic variables that characterize the movement patterns utilized by this group of children in achieving their optimal performance. The underlying idea is that by comparing test results and movement kinematics one might gain more insight into the movement production of children than by just looking at the test results or by just using clinical movement observation. The children performed a pen and paper task, the flower trail (one of the sub‐tests of the Movement ABC) (Henderson and Sugden, 1992), on an XY‐tablet. We explored kinematic variables, such as trajectory length, movement time, velocity and pen pressure. It was found that, although girls with TS have a severe motor deficit, they are able to draw a line accurately between two narrow boundaries just as well as the control children (no significant difference in mean number of spatial errors). However, quantitative analysis revealed that girls with TS made a large amount of deviations from the optimal path such that their trajectory length increased with more than 10% per flower trail compared to the control group children. They also made more pen lifts and more changes in velocity. The study showed that children from the two groups may reach the same basic accuracy performance level by using very different strategies. Kinematic registration of fine motor tasks holds promise in gaining more insight into how clinical groups cope with their specific motor problems. Copyright © 2003 John Wiley & Sons, Ltd.     

Effect of Instructions Prioritizing Speed or Accuracy on Kinematics and Kicking Performance in Football Players

The authors' purpose was to investigate if there is a speed accuracy trade-off in soccer kicking by using instructions prioritizing velocity, accuracy, or both upon soccer kicking performance and kicking direction in experienced soccer players. In addition, kinematics were measured to investigate the eventual differences in performance. Thirteen experienced male footballers performed penalty kicks with different instructions prioritizing velocity, accuracy or both. Three-dimensional kinematics, together with maximal ball velocity and hitting accuracy, were measured on all kicks. The main findings were that when the main aim was accuracy, accuracy increased, while the velocity reduced, which supports Fitts' law (Fitts, 1954 Fitts, P. M. (1954). The information capacity of the human motor system in controlling the amplitude of movement. Journal of Experimental Psychology, 47, 381–391.[Crossref], [PubMed] , [Google Scholar]). In addition, kicking accuracy was higher when kicking to the contralateral side. The slower ball velocity was caused by lower segmental and in run velocities. These lower segmental velocities were mainly caused by the lower maximal knee extension and pelvis rotation during the accuracy priority kicks.     

Oral kinematics: examining the role of edibility and valence in the in-out effect

Previous research has revealed a stable preference for words with inward consonantal-articulation patterns (from the front to the back of the mouth; e.g. BENOKA), over outward-words (from the back to the front; e.g. KENOBA). Following the oral approach-avoidance account suggesting that the in–out effect is due to the resemblance between consonantal-articulations patterns and ingestion/expectoration, recent findings have shown that when judging inward-outward names for objects with particular oral functions, valence did not modulate the effect while the oral function did. To replicate and examine further the role of edibility and valence in shaping the in–out effect, we asked participants (N?=?545) to rate inward and outward names for edible and non-edible products while controlling for valence. Results revealed that the motor-to-affect link was only observed for edible products, regardless of valence.     

Lower limb tri-joint synchrony during running gait: A longitudinal age-based study

Biomechanical research exploring the age-based mechanics of running gait can provide valuable insight into the reported decline in master endurance running performance. However, few studies have shown consistent biomechanical differences in the gait of trained distance runners compared to their younger counterparts. It might be that differences occur in the interaction between joints. The aim was to explore the differences in tri-joint synchrony of the lower limb, quantified through cluster phase analysis, of runners at 50 years of age compared to seven years later. Cluster phase analysis was used to examine changes in synchrony between 3 joints of the lower limb during the stance phase of running. Ten male, endurance-trained athletes M50 (age = 53.54 ± 2.56 years, mass = 71.05 ± 7.92 kg) participated in the study and returned after seven years M57 (age = 60.49 ± 2.56 years, mass = 69.08 ± 8.23 kg). Lower limb kinematics (Vicon, 120 Hz) and ground reaction forces (Kistler, 1080 Hz) were collected as participants performed multiple trials at a horizontal running velocity = 3.83 ± 0.40 m·s⁻¹ over the force plate. Significant increase (31%) in rate of force development in the absorption phase, and significantly reduced sagittal plane knee joint range of motion (30.50 v 23.68°) were found following the seven years of ageing. No further discrete single joint measures were significantly different between M50 and M57. Joint synchrony between the hip, knee and ankle was significantly higher at M57 compared to M50 during the absorption phase of stance. The force attenuation strategy is compromised after seven years of ageing, which is associated with more synchronous movements in the lower limb joints. Increased joint synchrony as a function of age could be a mechanism associated with this key injury provoking phase of running gait.     

Why do we need perceptual content?

Most representationalists argue that perceptual experience has to be representational because phenomenal looks are, by themselves, representational. Charles Travis (2004 Travis, C. (2004). The silence of the senses. Mind, 113, 57–94.[Crossref], [Web of Science ®] , [Google Scholar]) argues that looks cannot represent. I argue that perceptual experience has to be representational due to the way the visual system works.     

Effect of Transient Perturbations of Short-Term Memory on Target-Directed Blind Locomotion

It is difficult to walk without vision to a nearby destination if there is a time delay between watching the destination and walking toward it. Indeed, path deviation occurred when delays were introduced before initiating straight ahead blindfolded walking (R. A. Tyrrell, K. K., Rudolph, B. G., Eggers, &; H. W. Leibowitz, 1993 Tyrrell, R. A., Rudolph, K. K., Eggers, B. G., &; Leibowitz, H. W. (1993). Evidence for the persistence of visual guidance information. Perception &; Psychophysics, 54, 431–438.[Crossref], [PubMed] , [Google Scholar]). The questions are whether the location of a 60-s delay in the walking path and whether performing a cognitive task during the delay influence the accuracy in reaching a previously seen target while walking without vision. Thirty young adults walked blindfolded and stopped when they believed they had reached a target at 8 m. Delays were 60 s in duration, were located at 0, 4, and 7 m, and involved waiting or backward counting. Significant differences were found between 0-m and 4-m delay locations for distance to target, distance travelled and path deviation (p < .05). Significant effect of backward counting during the 60-s delay was found at the 0-m delay for distance travelled (p < .05). The interaction between retaining visual guidance information during 60 s and performing a cognitive task likely influenced target-directed blind navigation.     

Shaping of Reach-to-Grasp Kinematics by Intentions: A Meta-Analysis

When we reach to grasp something, we need to take into account both the properties of the object we are grasping and the intention we have in mind. Previous research has found these constraints to be visible in the reach-to-grasp kinematics, but there is no consensus on which kinematic parameters are the most sensitive. To examine this, a systematic literature search and meta-analyses were performed. The search identified studies assessing how changes in either an object property or a prior intention affect reach-to-grasp kinematics in healthy participants. Hereafter, meta-analyses were conducted using a restricted maximum likelihood random effect model. The meta-analyses showed that changes in both object properties and prior intentions affected reach-to-grasp kinematics. Based on these results, the authors argue for a tripartition of the reach-to-grasp movement in which the accelerating part of the reach is primarily associated with transporting the hand to the object (i.e., extrinsic object properties), the decelerating part of the reach is used as a preparation for object manipulation (i.e., prepare the grasp or the subsequent action), and the grasp is associated with manipulating the object's intrinsic properties, especially object size.     

The Smith-Walley Interpretation of Subjective Probability: An Appreciation

The right interpretation of subjective probability is implicit in the theories of upper and lower odds, and upper and lower previsions, developed, respectively, by Cedric Smith (1961) and Peter Walley (1991). On this interpretation you are free to assign contingent events the probability 1 (and thus to employ conditionalization as a method of probability revision) without becoming vulnerable to a weak Dutch book. Special Issue Formal Epistemology I. Edited by Branden Fitelson     

Neurones miroir, résonance et cognition sociale

Mirror neurons were discovered in the 1990's by cognitive neuroscientists from Parma. How central are mirror neurons in primates, social cognition. Do mirror neurons enable an observer to match the agent's observed movements onto her own motor repertoire? Does this matching enable the observer to represent the agent's intention, as argued by Rizzolatti et al? A positive answer to these questions can't be provided unless one assumme that mirror neurons compute the goal of an action by means of a “forward model” of the perceived action. However, the experimental evidence rather suggests that mirror neurons compute the motor means for achieving the desired goal, in accordance with an “inverse model” of the perceived action.     

Music Sight-Reading Skill in Flute Players

This article reports an investigation of factors related to music sight-reading skill. Flute players (N = 30) performed six tasks: (a) sight-reading standard music, (b) sight-reading random music, (c) recall of music notation, (d) recall of letters, (e) eye-performance span, and (f) choice reaction time for playing individual notes. Sight-reading ability was significantly correlated with eye-performance span (.85), and music recall (.80), but not with letter recall (-.39), thus replicating results of previous work with pianists. Sight-reading skill was correlated with choice reaction time to notes (- .54), and there was a significant partial correlation between sight-reading skill and eye-performance span, with music-reading ability controlled. These results are consistent with the idea that increased skill involves both the speed-up of individual processing stages, and an increase in the degree to which these stages operate in parallel.