Agility, gnosis, and graphaesthesia for the toes and fingers in children: normative data (ages 7-14 years)

The differential representation of the toes/feet and fingers/hands along the medial and lateral surfaces of the cerebral cortices, respectively, may have diagnostic utility. Normative data for errors for toe and finger graphaesthesia and gnosis, as well as foot and finger agility, were collected for 86 children (ages 7 to 14). The fingers were more agile than the feet, and the right side of the body was more agile than the left side, regardless of age. A marked improvement in toe gnosis, but not in finger gnosis occurred in children after 11-12 years of age. A statistically significant interaction between laterality and gender was due to the greater numbers of errors for both toe and finger gnosis, displayed by girls for the left sides of their bodies compared to their right sides. This discrepancy was not significant for boys.     

Enumeration skills in Down syndrome

Individuals with Down syndrome (DS) exhibit various math difficulties which can be ascribed both to global intelligence level and/or to their atypical cognitive profile. In this light, it is crucial to investigate whether DS display deficits in basic numerical skills. In the present study, individuals with DS and two groups of typically developing (TD) children matched for mental and chronological age completed two delayed match-to-sample tasks in order to evaluate the functioning of visual enumeration skills. Children with DS showed a specific deficit in the discrimination of small numerosities (within the subitizing range) with respect to both mental and chronological age matched TD children. In contrast, the discrimination of larger numerosities, though lower than that of chronological age matched controls, was comparable to that of mental age matched controls. Finally, counting was less fluent but the understanding of cardinality seemed to be preserved in DS. These results suggest a deficit of the object tracking system underlying the parallel individuation of small numerosities and a typical – but developmentally delayed – acuity of the approximate number system for discrimination of larger numerosities.     

一种手指康复装置的机构与控制实验

背景：临床证实,在患者肢体手术后或脑神经损伤的早期康复及自发恢复期间,实施连续被动运动可以补偿患者主动运动的不足,增大其肢体活动度,同时减少相应的并发症。 目的：以正常人体手指作对指运动时手指末端轨迹(预期轨迹)参数为基础设计完成手指康复训练机械手。 方法：以连续被动运动康复理论为基础设计了一种手指康复训练机械手,该机械手主要包括四指机构和拇指机构,采用步进电机进行驱动,以实现人体拇指和四指的对指运动。 结果与结论：针对实现不同长度手指的康复要求,实施了机构对指运动实验,机构末端轨迹与预期轨迹之间的相对误差约为2%,由此表明了机构设计及控制方法的可行性,并能够较好满足患者拇指和四指对指运动的康复需求,实验结果验证了该机械手能较好的实现预期运动。下一阶段,将在现有控制实验的基础上实施真人手指康复训练实验。     

Analog numerical representations in rhesus monkeys: evidence for parallel processing

Monkeys have been introduced as model organisms to study neural correlates of numerical competence, but many of the behavioral characteristics of numerical judgments remain speculative. Thus, we analyzed the behavioral performance of two rhesus monkeys judging the numerosities 1 to 7 during a delayed match-to-sample task. The monkeys showed similar discrimination performance irrespective of the exact physical appearance of the stimuli, confirming that performance was based on numerical information. Performance declined smoothly with larger numerosities, and reached discrimination threshold at numerosity "4." The nonverbal numerical representations in monkeys were based on analog magnitudes, object tracking process ("subitizing") could not account for the findings because the continuum of small and large numbers shows a clear Weber fraction signature. The lack of additional scanning eye movements with increasing set sizes, together with indistinguishable neuronal response latencies for neurons with different preferred numerosities, argues for parallel encoding of numerical information. The slight but significant increase in reaction time with increasing numerosities can be explained by task difficulty and consequently time-consuming decision processes. The behavioral results are compared to single-cell recordings from the prefrontal cortex in the same subjects. Models for numerosity discrimination that may account for these results are discussed.     

Enhancement of force after action observation: behavioural and neurophysiological studies

We tested here the hypothesis that observing others' actions can facilitate basic aspects of motor performance, such as force production, even if subjects are not required to immediately reproduce the observed actions and if they are not aware that observation can form the basis for procedural training. To this end, we compared in healthy volunteers the effects of repeated actual execution (MOV) or observation (OBS) of a simple intransitive movement (abduction of the right index and middle fingers). In a first experiment, we found that both actual and observational training significantly increased the finger abduction force of both hands. In the MOV group, force increases over pre-training values were significantly higher in the trained than in the untrained hand (50% versus 33%), whereas they were similar for the two hands in the OBS group (32% versus 30%). No force change was found in the control, untrained group. In a second experiment, we found that both training conditions significantly increased the isometric force exerted during right index finger abduction, whereas no post-training change in isometric force was found during abduction of the right little finger. Actual performance, imagination and, to a lower extent, observation of fingers movement enhanced the excitability of the corticospinal system targeting the first dorsal interosseus muscle, as tested by transcranial magnetic stimulation; pre- and post-training effects were of similar magnitude. These results show a powerful, specific role of action observation in motor training, likely exerted through premotor areas, which may prove useful in physiological and rehabilitative conditions.     

Evaluation of ADL in patients with Hunter disease using FIM score

MPS type II (Hunter disease) results from deficiency of the lysosomal enzyme iduronate-2-sulfate sulfatase. Two forms of the disease have been recognized, based on absence or presence of progressive intellectual deterioration. This study aimed to assess activities of daily life (ADL) in 27 Hunter disease-affected Japanese patients, using a modified version of the functional independence measure (FIM). Scores of ADL for patients with a severe phenotype were significantly lower than those of control children. Total scores were highest around 5-7 years old, then progressively decreased, and scores <40 were obtained with patients aged 9 years or more. In contrast to motor scores, cognitive scores decreased rapidly, generally reaching a minimum score at around 7 years old. On the other hand, in children with attenuated phenotype, total scores increased progressively with age similar to control children. Two children who had the highest grades at elementary school showed maximum scores. However, all adult patients did not show maximum total scores, and 3 of 4 patients over 25 years old showed decreasing scores. Two children and two adults showed significant lower scores compared with other patients, suggesting an intermediate form from the view of ADL. This study elucidated the precise clinical state of Hunter disease with distinct numerical scores, in addition to previously described narrative data. To maintain the QOL of the patients better, they and their family need to know what specific difficulties they encounter, in which period they encounter them, and what support can fix them. Further ADL investigations with larger populations and/or long-term sequential examination could help the patients and family to understand them well.     

Dyslexia and across-hands finger localization deficits

Two experiments on finger localization are reported. Experiment 1 compared children who were poor readers with two groups of children matched to poor readers for sex and either age (CA controls) or reading age (RA controls). The participant's hands were kept out of his or her sight in a semi-open box while the fingers of one hand were lightly touched by the experimenter. The participant's task was to indicate, using the thumb of either the same hand (within-hand condition) or the opposite hand (across-hands condition) to respond, the finger(s) which had been touched by the experimenter. Performance was significantly impaired in the across-hands condition compared with the within-hand condition. Experiment 2 was carried out with dyslexic adults and a control group of normal readers. Using the same method of responding as in Experiment 1, a significant deficit in the across-hands condition compared to the within-hand condition was found for both groups. The effect was also obtained for both groups when participants were required to point to the relevant fingers on a photograph of a hand rather than use the thumb of the opposite hand to respond. The results are discussed in relation to the hypothesis of a deficit in inter-hemispheric transfer of tactile information in dyslexia.     

Functional asymmetry in the reading of Braille

Difference between right and left handed reading was investigated in two experiments. In the first, summarised previously, children were found to be faster and more accurate when reading with fingers of the left than the right hand. In the second study, using adults, no difference in speed was found, but fewer mistakes were made when reading with the left than with the right middle finger. The findings are discussed in relation to training effects and cortical asymmetry.     

A functional analysis of finger sucking in children

In this investigation, the authors experimentally assessed the functions of finger sucking for 3 typically developing children ages 6, 7, and 14. In Experiment 1, a parent-conducted functional analysis, completed in each child's natural environment, showed that each of the children's finger sucking was most likely to occur when the child was alone, suggesting that the behaviors were maintained by automatic reinforcement. Experiment 2 involved assessing the nature of the sensory stimulation that maintained finger sucking by attenuating the sensory stimulation to the fingers via the use of Band-Aids and attenuating the sensory stimulation to the mouth with a mild numbing agent for 2 of the 3 children. For the 3rd child, mouthing objects were made available noncontingently to determine whether access to such items would result in low levels of finger sucking, suggesting reinforcer substitutability. Results of these analyses suggested that finger sucking was maintained by both oral and digital stimulation for 2 children and by oral stimulation for the 3rd.