Hand Grip and Load Force Coordination of the Ipsilesional Hand of Chronic Stroke Individuals

Object manipulation depends on a refined control of grip force (GF) and load force (LF). After a brain injury, the GF control is altered in the paretic hand but what happens with the non-paretic hand is still unclear. In this study, we compared the GF control and GF–LF coordination of the non-paretic hand of 10 stroke individuals who suffered right brain damage (RBD) and 10 who suffered left brain damage (LBD), with 20 healthy individuals during lifting and oscillation task, using an instrumented object. GF was recorded with a force transducer, and LF was estimated from the object weight and acceleration. Overall, the ipsilesional hand of stroke individuals, independent of the lesion side, presented similar GF control and GF–LF coordination. However, LBD individuals took longer to start lifting the object, which may be due to the need of more time to obtain somatosensory information from the contact with the object. The findings indicate that stroke individuals preserve their ability to control and coordinate GF and LF when using their ipsilesional hand for object manipulation and the left hemisphere may play an essential role in the processing of somatosensory information needed for the GF control.     

Toward an Epistemology of the Hand

Western philosophy has been greatly influenced by visual metaphors. Knowing something has commonly, yet implicitly, been conceptualized as seeing something clearly, learning has been framed as being visually exposed to something, and the mind has been understood as a ‘mirror of nature’. A whole ‘epistemology of the eye’ has been at work, which has had significant practical implications, not least in educational contexts. One way to characterize John Dewey’s pragmatism is to see it as an attempt to replace the epistemology of the eye with an epistemology of the hand. This article develops the epistemology of the hand on three levels: A level of embodiment and metaphors, of craftsmanship and social practices, and of schooling and education.     

What the Eye Tells the Hand

The information flow necessary to coordinate hand movements with vision is summarized. A series of experiments was performed which quantitatively examined and confirmed the summary. In general, an information-theoretic approach was used. It was confirmed that the speed and accuracy of hand movements are in a reciprocal relationship. The accuracy of a movement is more sensitive to a loss of visual information than the pacing mechanism. Both speed and accuracy are sensitive to withdrawal of information to maintain posture. It is suggested that the retrieval of a movement pre-program is disturbed by afferent “noise.” The contribution of visual information to controlling standing posture, arm and shoulder movement, and wrist movement were investigated.     

被试自身人手初始状态对心理旋转加工的影响:眼动研究

利用眼动追踪技术,探讨在左右手判断任务条件下人手心理旋转加工是否受到被试自身人手初始状态的影响.两个实验的反应时数据和眼动数据均发现:(1)心理旋转加工受被试自身人手初始状态的影响,表现出一致性效应;(2)显著的内旋效应;(3)被试心理旋转加工时注视点取样存在着不均衡性.这些结果表明:在左右手判断任务中,心理旋转加工的对象是被试自身人手的表象,是自我参照的心理旋转,并且内旋效应是由被试对自身人手表象进行旋转时受到人手生理机制约束所致,而不是被试旋转刺激图片的表象由"生理机制约束知识"影响所致.     

蛋白质化学与分子生物学携手前进

蛋白质化学的发展历经了几次重大的转变,分析仪器的商品化使蛋白质从实验室走向市场;一级结构信息促进了多肽的合成与改造;分子生物学技术的成熟使人们从设计改造功能蛋白转向设计基因,并尝试进行基因治疗和ＤＮＡ免疫。这些转变,使蛋白质化学技术与分子生物学技术成为人们手中的工具,为人们研究生命拓宽了思路。     

Hand dominance influences the processing of observed bodies

In motor tasks, subgroups of lefthanders have been shown to differ in the distribution of attention about their own bodies. The present experiment examined whether similar attentional biases also apply when processing observed bodies. Sixteen right handers (RHs), 22 consistent left handers (CLHs) and 11 relatively ambidextrous inconsistent left handers (ILHs) performed an own body transformation task in which they were instructed to make speeded left–right judgements about a schematic human figure. Attentional biases associated with handedness were found to extend to observed bodies: CLHs’ judgements were faster to the figure’s left side, while ILHs, like RHs, showed facilitated performance to the figure’s right side. These results demonstrate a novel embodiment effect whereby the processing of a static schematic human figure is modulated by an individual’s personal motor capabilities. This finding suggests that motor simulation may contribute to whole body perception in the absence of actual or implied actions.     

On the Hand Transport Component of Prehensile Movements

Jeannerod (1981) proposed that prehensile movements involve two independent visuomotor channels that are responsible for hand transport and hand aperture. In many studies, the movement of a marker placed on the wrist has been used as an index of hand transport because wrist movement is unaffected by the movements of the digits responsible for hand aperture. In the present study, the spatial paths of the wrist, index finger, and thumb of 5 adults, each performing 50 reaching movements, were measured with a WATSMART movement tracking system, and their variability was analyzed. The measures of movement variability suggest that the motor system is more concerned with thumb position than with wrist position during hand transport. Although the wrist is a technically convenient index of hand transport, the thumb may be a more appropriate index from the point of view of motor control.     

Differentiation of Assaultive Delinquents with the Hand Test

The AOS score on the Hand Test significantly differentiated assaultive from non-assaultive delinquents, correctly categorizing 78 percent of the subjects.     

Knowing at Second Hand

Participants on both sides of the contemporary debate between reductionism and anti‐reductionism about testimony commonly describe testimonial knowledge as knowledge acquired at second hand. I argue that fully appreciating the distinctive sense in which testimonial knowledge is secondhand supports anti‐reductionism over reductionism but also that it supports a particular kind of anti‐reductionism very different from that typically offered in the literature. Testimonial knowledge is secondhand in the demanding sense of being justified by the authority of a speaker where this requires that epistemic responsibility for meeting challenges to the audience's testimonial knowledge is shared between speaker and audience. The epistemic credentials of testimonial knowledge are in this sense importantly interpersonal.     

Hand Preference in India

The degree of asymmetric handedness was measured by a 22-item hand preference questionnaire in a sample of 442 Indian subjects. Factor analysis of the data for right-handers yielded four item-clusters: Gross activities, skilled activities (general), skilled activities (specific), and activities subject to social pressure. Identical analysis for left-handers yielded three item-clusters: Activities that are executed with difficulty, with ease, and with greater frequency. The degree of asymmetric handedness in right-handers was positively (high) correlated with an index of social pressure against left-hand use, especially for the items, writing and eating. The correlation was negative (moderate) in left-handers, however, who had preferred the right hand for eating purposes.     

Test-retest reliability of the Hand Test with normal subjects

The Hand Test (Wagner, 1962) was administered to 71 subjects; 14 days later these subjects were again administered the Hand Test. Results indicated the Hand Test is a highly reliable measure of an individual's behavioral action tendencies.     

Use of the Hand Test in the Assessment of Combat-Related Stress

This study investigated the effectiveness of the Hand Test in discriminating the differential symptomatology of posttraumatic stress (PTS) in Vietnam combat veterans (VCVs). Participants were 108 VCV outpatients, 85 of whom met the Diagnostic and Statistical Manual of Mental Disorders (4th ed. [DSM-IV]; American Psychiatric Association, 1994) criteria for posttraumatic stress disorder (PTSD), and 23 patients that were found to meet some, but not the minimum criteria, required for a diagnosis of PTSD by the DSM-IV. The latter group of patients was classified into a subclinical PTSD, posttraumatic stress symptoms (PTSS) group. Results showed higher levels of overall psychopathology, a vulnerable capacity for coping, and a tendency for feelings of inadequacy and inferiority in the PTSD group. The PTSD group also exhibited more limited interaction with the world around them than the PTSS group, which may be indicative of withdrawal, apathy, or a lack of concern with environmental activities and goals. These findings are discussed in relation to the assessment, understanding, and treatment of PTS symptomatology and PTSD.     

Hand Test Indicators of Antisocial Behavior

The Hand Test Acting Out Score (AOS) and to a limited degree other scores were studied in relationship to offense type of 614 military prisoners, their subsequent disciplinary problems in adjusting to confinement, and an Army measure of mental ability. Significant differences were observed between the mean AOSs of Ss who had committed offenses against people and against property and between Ss who subsequently were model prisoners and disciplinary offenders. The mental ability measure was minimally related to Hand Test response categories. Considerable overlap was observed in AOS distributions of the varying antisocial groups and the AOS was felt to be of questionable value in predicting individual antisocial behavior in confinement.