Support-specific modulation of grip force in individuals with hemiparesis

OBJECTIVE: To investigate whether use of auxiliary sensory input will result in modulated grip force. DESIGN: Case-control study. SETTING: Free-standing acute inpatient rehabilitation hospital. PARTICIPANTS: Six people with unilateral hemiparesis due to unilateral stroke and 6 control subjects without neurologic disorders. INTERVENTIONS: Seated subjects lifted and transported the same object under 3 different conditions: with no support, with the target arm positioned on a freely moving skateboard, and with a finger from the subject's contralateral hand lightly touching the wrist of the target arm. MAIN OUTCOME MEASURES: Peak grip force and temporal coupling between the grip force and lift-off of the object. RESULTS: All subjects were able to better regulate grip force when provided with additional sensory input. Light finger touch resulted in decreased grip force, as did skateboard use ( P <.05). Subjects with hemiparesis showed 2 times longer latency between grip-force application and lift-off of the object ( P <.05). CONCLUSIONS: Statistically significant grip-force reduction was noted with both support aids. These findings could have implications in clinical and rehabilitative areas.     

Tactile functions after cerebral hemispherectomy

Patients that were hemispherectomized due to brain lesions early in life sometimes have remarkably well-preserved tactile functions on their paretic body half. This has been attributed to developmental neuroplasticity. However, the tactile examinations generally have been fairly crude, and subtle deficits may not have been revealed. We investigated monofilament detection and three types of tactile directional sensibility in four hemispherectomized patients and six healthy controls. Patients were examined bilaterally on the face, forearm and lower leg. Normal subjects were examined unilaterally. Following each test of directional sensibility, subjects were asked to rate the intensity of the stimulation. On the nonparetic side, results were almost always in the normal range. On the paretic side, the patients' capacity for monofilament detection was less impaired than their directional sensibility. Despite the disturbed directional sensibility on their paretic side the patients rated tactile sensations evoked by the stimuli, on both their paretic and nonparetic body halves, as more intense than normals. Thus, mechanisms of plasticity seem adequate for tactile detection and intensity coding but not for more complex tactile functions such as directional sensibility. The reason for the high vulnerability of tactile directional sensibility may be that it depends on spatially and temporally precise afferent information processed in a distributed cortical network.     

Migration and fusion of tactile sensation--premorbid susceptibility to allochiria, neglect and extinction?

Migration of tactile sensation was found to occur very frequently in about 25% of normal people (High Error subjects) and very infrequently in others. When synchronous stimuli touched the two hands, if the unattended stimulus was modulated when the attended one was not (and was thus more salient) it "migrated" to the attended hand and fused with or replaced the attended stimulus. However, latencies reflecting congruence and incongruence of simultaneous stimuli showed that their identities on each hand had been (nonconsciously) registered veridically. Subsequent experiments, involving Focused and Divided Attention without speed pressure showed that mislocation errors in these subjects (i) were not due to confusion about location of otherwise perceptually distinct stimuli, (ii) nor to speed demand, (iii) nor to relative salience per se, (iv) were immune to attentional manipulation and practice in most subjects, (v) required a stimulus on the attended hand, and (vi) reflected a changed experience. Finally the same subjects rated similarity of the attended stimulus when accompanied by a distractor to each stimulus alone. Scaling distributions tested against a sampling model showed that most High Error subjects experienced a fusion of the stimuli, some experienced a replacement, and Low Error subjects experienced neither. The individual difference appears to be in attentional separability and spatial binding of tactile stimuli. Mislocation to the focus of spatial attention is common in healthy people, especially when binding is prevented. The present phenomenon appears equivalent to allochiria, but also accounts for phenomena in neglect and extinction, and suggests a premorbid susceptibility to spatial migration and integration that can be exaggerated by brain damage.     

Audiotactile interactions in roughness perception

The sounds produced when we touch textured surfaces frequently provide information regarding the structure of those surfaces. It has recently been demonstrated that the perception of the texture of the hands can be modified simply by manipulating the frequency content of such touch-related sounds. We investigated whether similar auditory manipulations change people's perception of the roughness of abrasive surfaces (experiment 1). Participants were required to make speeded, forced-choice discrimination responses regarding the roughness of a series of abrasive samples which they touched briefly. Analysis of discrimination errors verified that tactile roughness perception was modulated by the frequency content of the auditory feedback. Specifically, attenuating high frequencies led to a bias towards an increased perception of tactile smoothness. In experiment 2, we replicated the rubbing-hands manipulation of previous experimenters while participants rated either the perceived roughness or wetness of their hands. The wetness scale data replicated the results in the literature, while the roughness scale data replicated the result from experiment 1. A final experiment showed that delaying the auditory feedback from the hand-rubbing reduced the magnitude of this parchment-skin illusion. These experiments demonstrate the dramatic effect that auditory frequency manipulations can have on the perceived tactile roughness and moistness of surfaces, and are consistent with the proposal that different auditory perceptual dimensions may have varying salience for different surfaces.     

Effect of light finger touch on postural sway after lower-limb muscular fatigue

OBJECTIVE: To investigate whether a light finger touch can compensate for the increased postural sway induced by lower-limb muscular fatigue. DESIGN: Before-after trials. SETTING: General community. PARTICIPANTS: Nine healthy university students (mean age, 23.8+/-2.6y; mean body weight, 72.7+/-6.9 kg; mean height, 177.2+/-7.5 cm). INTERVENTIONS: Participants stood with their feet together and eyes closed. They were asked to sway as little as possible in 4 conditions: no fatigue/no touch, no fatigue/touch, fatigue/no touch, and fatigue/touch. Calf muscle fatigue was induced by having participants stand on their toes until exhaustion. Touch conditions involved a gentle light touch with the right index finger on a nearby surface at waist height. MAIN OUTCOME MEASURES: Center of pressure displacements were recorded by using a force platform. RESULTS: Light finger touch resulted in decreased postural sway in the no-fatigue and fatigue conditions. Interestingly, this stabilizing effect was more accentuated in the fatigue condition. CONCLUSIONS: Results suggest that the contribution of the haptic cues from the finger for regulating postural sway increases after muscular fatigue. These findings could have implications in clinical and rehabilitative areas.     

Cross-modal performance: behavioural processes, phylogenetic considerations and neural mechanisms

Issues relating to cross-modal performance (CMP) are examined from various points of view, with major emphasis on phylogenetic comparisons and neurological mechanisms. Although it now seems likely that certain distinctions that were made based on training procedures (i.e., among transfer, matching, and recognition) have no functional significance, research on this topic has demonstrated how the level of performance is affected by certain task variables (such as number of trials in the first modality). It has not yet been shown that these relationships differ from ones that would be seen in comparable within-modal studies. Overall phylogenetic differences specific to CMP cannot be sustained from the data for humans, apes, monkeys, and non-primates. However, two possible differences - one phylogenetic and one ontogenetic — require further study. Metaphorical matching has not been demonstrated in nonhumans, and it may be the case that ‘categorical’ CMP appears earlier in development than ‘specific’ CMP. Efforts to establish that CMP is mediated by representations localized in regions of polysensory neural convergence have not provided convincing evidence, so that ‘leakage’ between perceptual/memory systems previously considered to be modality-specific is proposed as the mechanism for CMP. Based primarily upon findings from a study using 2-DG, the suggestion is made that one pathway for such leakage is through the ventral claustrum. Polysensory areas of cortex may play a special role during the initial formation of a multisensory engram.     

基于VOXEL-MAN操作平台肩(骨谬)穴的力反馈研究

目的:通过在肩(骨谬)穴周围组织三维重建的基础上,探讨在该穴进针时的力学虚拟,便于初学者对穴位进针有感性认识.方法:在VOXEL-MAN操作平台中,通过对肩(骨谬)穴相关组织进行分割和数学建模的方式进行重建,即视觉再现;并构建力学模型,与虚拟人相关数据相融合,即触觉再现;联通视觉再现模块和触觉再现模块,实现力反馈仪和虚拟人操作平台之间数据交流.结果:在Linux系统下,通过力反馈仪,操作者可以体验肩(骨谬)穴进针时,针尖穿过各组织以及均匀提插时的力学变化.结论:在VOXEL-MAN操作平台的基础上,通过力反馈仪可以较为完美地再现肩(骨谬)穴进针时视觉和触觉的变化,以便于初学者临摹学习和应用.     

抚触干预对早产儿神经行为影响的临床观察

目的 探讨抚触对早产儿神经行为的影响.方法 选择我院出生的早产儿60例,系孕周31～36周自然分娩或选择性剖宫产儿,随机分为抚触组和对照组各30例.在综合护理措施及育儿指导相同的情况下,抚触组增加抚触护理并随访半年.对两组早产儿在出生后1个月进行神经行为评分(NBNA):3个月、6个月进行智能发育指数(MDI)和心理运动发育指数(PDI)测查及对比分析.结果 抚触组在出生后1个月NBNA与对照组比较差异有统计学意义(P<0.01);3个月、6个月两组MDI和PDI测查差异亦有统计学意义(P<0.05).结论 抚触对早产儿神经系统有良好作用.     

Is OSNA better than imprint cytology for intraoperative diagnosis of cancer involvement of axillary sentinel node in breast cancer?

ObjectiveThe study aim was to establish Sensitivity, Specificity, Positive Predictive Value, Negative Predictive Value (NPV), and Accuracy Values of both imprint cytology (IC) and the OSNA assay for intraoperative assessment of axillary sentinel node (SN) cancer involvement in breast cancer. Specifically, we wished to find out if true positive and false negative results of IC were associated to axillary lymphadenectomy (ALND). Also, we addressed a comparative cost analysis between techniques.Methods244 patients treated for breast cancer in the Breast Unit of Hospital Germans Trias i Pujol from 2011 to 2015 were prospectively included. A transversal, consecutive design was applied to assess IC compared to the reference test (OSNA). Inclusion criteria were: T1 and T2 tumors with negative nodes, both clinically and on ultrasound.ResultsSensitivity of IC for macrometastases was 70%. The NPV of IC for macrometastases was 95,75%. Accuracy of IC was 96,12%. In the comparative cost analysis, the release time of results for OSNA doubled that of IC and was associated with an increased cost of € 370.ConclusionsIC has been stated as a good technique for intraoperative cancer involvement SN with high sensitivity and NPV compared to the OSNA assay. It allows keeping the whole node tissue and thus the possibility of improved histopathological evaluation, which can be useful for adjuvant, and offers the advantage of being less time consuming. Cost analysis shows a higher cost for OSNA, which may exceed the benefit of sorting out false negatives from IC.     

触控式省水阀在综合性医院应用的除尘能力评价

目的通过触控式水阀的除尘能力研究,验证其是否适合在医院环境中使用。方法收集医院环境中的自然落尘,溶于清洁自来水中,人工将其附着于触控头上,干燥24h后开启自来水,将冲脱下来的自来水分段收集,检测其浊度和电导率,观察洗脱效果。结果附着物能在20s内被快速洗脱,将自来水的吸光度值降为零,电导值降到0．018s／cm．清洁度与原自来水检测值一致。结论触控式水阀具备自动除尘能力,能在综合性医院安全应用。