Relationship between lower limb coordination and walking speed after stroke: an observational study

BackgroundAlthough lower limb muscle strength is associated with walking performance in people after stroke, even when there is good strength, walking speed may remain slower than normal, perhaps due to incoordination.ObjectiveThe aim of this study was to examine the relationship between walking speed and lower limb coordination in people with good strength after stroke.MethodsAn observational study was conducted with 30 people with stroke and 30 age-matched controls. Inclusion criteria for stroke were good lower limb strength (i.e., ≥Grade 4) and walking speed at >0.6 m/s without aids in bare feet (with recruitment stratified so that walking speed was evenly represented across the range). Walking performance was measured as speed during the 10-m Walk Test and distance during the 6-min Walk Test. Coordination was measured using the Lower Extremity Motor Coordination Test and reported in taps/s.ResultsStroke survivors walked at 1.00 (SD 0.26) m/s during the10-m Walk Test (64% of normal), walked 349 (SD 94) m during the 6-min Walk Test (68% of normal), and performed the Lower Extremity Motor Coordination Test at 1.20 (SD 0.34) taps/s with the affected side (64% of normal). Lower Extremity Motor Coordination Test scores for the affected side were statistically significantly correlated with walking performance in the 10-m Walk Test (r = 0.42, p = 0.02) and the 6-min Walk Test (r = 0.50, p = 0.01).ConclusionCoordination was related to walking performance, suggesting that loss of coordination may contribute to slow walking in this group of stroke survivors with good strength.Trial registration: ANZCTR12614000856617 (www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=366827).     

Knowledge and Attitudes of Health Personnel About Organ Donation: A Tertiary Hospital Example,Turkey

Objective

In order to increase limited organ donations, public awareness must be raised. It is also essential that health personnel have enough knowledge about organ donation. This research aims at determining health personnel knowledge and attitudes about organ donation in a tertiary hospital with an organ transplant center.

Contribution de la mesure de la pression intra-orale pour la compréhension des troubles de la coordination pneumophonique dans la dysarthrie parkinsonienne

Introduction

Parkinsonian dysarthria can alter oral communication of the patients in the long-term. Subthalamic nucleus (STN) stimulation represents an interesting therapeutic option, although it does not seem to improve axial signs, of which dysarthric speech. The objective of our study was to contribute to the evaluation of STN stimulation effects on speech impairment and in particular on pneumophonic coordination: this latter parameter can be assessed indirectly by evaluating the temporal progression of the intraoral pressure (IOP) during the expiratory phase; thus, IOP represents the transient expression of subglottal pressure (SGP).

Patients and method

Using a dedicated system (EVA2), 20 parkinsonian patients were recorded in ON and OFF STN stimulation conditions in order to evaluate IOP on three measurement points (2nd, 4th and 6th consonants P) during realization of the sentence “Papa ne m’a pas parlé de beau-papa” (“Daddy did not speak to me about daddy-in-law”) which corresponds to a breath group. Eleven control subjects were recorded in parallel in order to define reference measurements.

Results

STN stimulation improved significantly IOP at the level of the initial measurement points (2nd P and 4th P), with an effect of convergence at the level of the third point (6th P) where the difference between OFF and ON STIM conditions was not significant any more. In addition, the performance of the patients ON STIM remained much lower than that of the control subjects.

Conclusion

Our results raise the significant concept that IOP measurement can be regarded as a relevant indicator for dysarthria in Parkinson's disease. They also show that the improvement of pneumophonic coordination by STN stimulation is restricted to the initial period of the expiratory phase, confirming again the mitigated and controversial effect of STN stimulation on axial signs.     

Biased wrist and finger coordination in Parkinsonian patients during performance of graphical tasks

Handwriting impairments in Parkinson's disease (PD) have been associated with micrographia, i.e. diminished letter size. However, dyscoordination of the wrist and fingers may also contribute to handwriting deterioration in PD. To investigate this hypothesis, right-handed PD patients and controls were tested in performance of three types of cyclic wrist and finger movements: drawing of two lines and a circle. The line drawing was performed with either simultaneous flexion and extension of the wrist and fingers (equivalent pattern resulting in a right-tilted line) or with wrist flexion/extension accompanied with finger extension/flexion (nonequivalent pattern resulting in a left-tilted line). Circle drawing required a specific phase difference between wrist and finger motions. Movements were performed with an inkless pen on a digitizer-tablet at two frequency levels. Consistent deformations of the circle into right-tilted ovals and lower variability in equivalent compared with nonequivalent lines revealed preference to produce right-tilted shapes. This preference became more apparent with increased movement speed and it was amplified in PD patients. Analysis revealed that the circle deformation emerged mainly due to reduction in relative phase, while wrist and finger amplitudes remained unchanged. The results suggest that PD causes deficit characterized by strong tendency to produce certain coordination patterns between wrist and finger motions. This deficit may significantly contribute to handwriting impairments in PD by reducing the dexterity in the production of the variety of shapes of the cursive letters. Furthermore, the deficiency revealed in wrist and finger coordination may represent a more general deficit affecting control of various multi-joint movements in PD.     

Reflections on Jacques Paillard (1920–2006) — A pioneer in the field of motor cognition

This article reviews the scientific contributions of Jacques Paillard (1920–2006), who strengthened substantially the role of physiological psychology in the field of movement neuroscience. His research began in 1947 under the direction of the French neurophysiologist, Alfred Fessard (1900–1982), with whom he then collaborated for 9 years while an undergraduate and then graduate student and junior faculty member in psychology at the University of Paris (the Sorbonne). Paillard moved to the University of Marseille in 1957 as a Professor of Psychophysiology. In parallel, he became a founding member and administrator of the Institute of Neurophysiology and Psychophysiology, which began in 1963 on the Marseille campus of the National Center of Scientific Research (CNRS). Paillard retired from his university and CNRS positions in 1991 but he continued seminal research until his demise. Paillard advanced understanding of higher brain influences on human spinal motor mechanisms and the functional role of proprioception as revealed in patients deprived of such sensibility. He remains best known, however, for his work on human motor cognition. He reasoned that brain “maps” of the external world are constructed by the body's own movements and the central effects of their resulting central and peripheral feedback. He proposed two levels of interactive brain processing for the planning and/or execution of a reaching movement: 1) a sensorimotor level, using body posture as a key reference; and 2) a “higher” cognitive level for accurate movement performance, using learned representations of the position and shape of the environmental components, including the body, itself.     

Joint-specific disruption of control during arm movements in Parkinson’s disease

The leading joint hypothesis (LJH) suggests distinct types of control (leading and subordinate) at different joints during multi-joint movements. Taking into account specific features of movements in Parkinson’s disease (PD), the LJH predicts distinct effect of PD on control of leading and subordinate joints: impaired interaction torque (INT) regulation should be emphasized at the subordinate joints, and impaired generation of muscle torque (MUS) magnitude should be more pronounced at the leading joint. This prediction was tested by studying three tasks of horizontal shoulder-elbow movements in PD patients and age-matched controls: cyclic line drawing, cyclic point-to-point, and discrete pointing movements. Each task included movements in different directions, providing both shoulder-lead and elbow-lead control patterns. Torque analysis supported the prediction, specifically for Tasks 2 and 3 in which movement targets were chosen to emphasize the shoulder- and elbow-lead control patterns. Patients did not exploit INT for motion generation as successfully as controls did, but only at the subordinate joint. Underproduction of MUS by PD patients was more apparent at the leading than subordinate joint. The results support joint-specific effect of PD on movement control. They also suggest that dyscoordination of joint motions in PD stems predominantly from impaired control of subordinate joints, while bradykinesia is associated more with control of the leading than subordinate joint. Possible contribution of the revealed impairments in joint control to some other movement features in PD is discussed. The study demonstrates the efficiency of the LJH application for revealing changes in joint control caused by motor disorders.     

Task-specific modulation of multi-digit forces to object texture

During multi-digit grasping both local and non-local digit force responses occur in response to changes in texture at selected digits depending on the grasp configuration. However, the extent to which the specific patterns of force distribution depend on the requirement to hold the object against gravity remains to be determined. In the present study, we examined whether grasp force sharing patterns are invariant when the constraint of maintaining the object orientation vertical against gravity is removed. We used changes in object texture to elicit force changes at single digits during two grasping tasks with different behavioral contexts. One task entailed holding an object against gravity (object hold [OH]). A second (force production [FP]) task consisted of generating lifting forces on an object clamped to the tabletop that were matched to those used during OH. Unlike OH, the FP task lacks the behavioral consequences associated with erroneous sharing of normal and tangential digit forces, e.g., object tilt. Ten subjects lifted and simulated lifting an instrumented object measuring grasping normal and vertical tangential forces at all five digits when the textures were uniformly high-friction sandpaper or low-friction rayon and when one digit contacted a different frictional texture than the other four digits. We found that in both tasks texture changes at individual digits elicited force changes at that digit as well as other digits. However, the specific pattern of force distribution changes differed during OH compared to FP. While subjects modulate the normal and tangential digit forces to different degrees depending on object texture and the grasping task, they ignore the requirement of moment equilibrium when this has no consequences on object orientation (FP task). These findings indicate that multi-digit force responses to texture revealed by previous studies are not obligatory and suggest that the behavioral context of a task should be considered when inferring general principles of multi-digit force coordination.     

The commissural transfer of the horizontal optokinetic signal in the rat: a c-Fos study

Using a precision grip, 12 participants horizontally oscillated a lightweight object at different movement frequencies (1.0, 1.5, and 2.0 Hz) under two types of elastic load. In the first (CENT), the center of oscillation coincided with the neutral position of the object in the elastic force field, leading to two peaks in load force (LF) per cycle of movement (2:1 frequency ratio). In the second (BACK and FRONT), the neutral elastic force position of the object was located outside the range of movement, thus leading to only one LF peak per cycle of movement (1:1 frequency ratio). Results showed that in BACK and FRONT the coupling between grip force (GF) and LF (as reflected by coefficients of correlations) remained strong for all movement frequencies. In contrast, this coupling decreased in CENT as movement frequency increased, with participants switching progressively from two to one GF modulation per cycle of movement. Specific evaluation of performance under conditions giving rise to comparable LF frequencies (CENT at 1.0 Hz vs. BACK/FRONT at 2.0 Hz) confirmed the effect of frequency ratio on GF–LF coupling. We conclude that the control of GF is more efficient when LF varies at the frequency of movement than when it varies at twice this frequency, especially when movement frequency is high. These results are interpreted in the context of coordination dynamics and forward modeling approach.     

静脉药物配置中心护士与药师的协调配合策略分析

目的探讨处理临床工作中静脉药物配置中心护士与药师协调配合的策略。方法结合静脉药物配置中心护士与药师岗位职责的界定和实际临床工作中的经验，采用问卷调查的方式对相关人员进行信息采集，并进行分析。结果通过对资料的分析，提出了协调静脉药物配置中心护士与药师工作的“职责明确，互相学习，互相尊重，双赢发展”十六字方针。结论静脉药物配置中心护士与药师的协调配合在医院临床工作中十分重要，于实践工作中总结的处理策略对于协调两者之间的关系具有一定的指导意义。     

Brain activation associated with motor skill practice in children with developmental coordination disorder: an fMRI study

Children with developmental coordination disorder (DCD) have difficulty in learning new motor skills. At present, it is not known whether these children employ a different set of brain regions than typically developing (TD) children during skilled motor practice. Using functional magnetic resonance imaging, we mapped brain activity associated with skilled motor practice of a trail-tracing task in 7 children with DCD and 7 age-matched controls (aged 8-12 years). We indexed change in motor performance as a reduction in tracing error from early practice to retention. Children with DCD showed less blood-oxygen-level-dependent signal as compared to TD children in a network of brain regions associated with skilled motor practice: bilateral inferior parietal lobules (Brodmann Area (BA) 40), right lingual gyrus (BA 18), right middle frontal gyrus (BA 9), left fusiform gyrus (BA 37), right cerebellar crus I, left cerebellar lobule VI, and left cerebellar lobule IX. While no statistically significant differences were detected, effect size testing revealed that children with DCD demonstrated poorer tracing accuracy than TD children at retention (d = 0.48). Our results suggest that, compared to TD peers, children with DCD demonstrate under-activation in cerebellar-parietal and cerebellar-prefrontal networks and in brain regions associated with visual-spatial learning. These data suggest a neurobiological correlation with impaired learning of motor skills in children with DCD, which will need to be confirmed with a larger sample.