Are postural adjustments during reaching related to walking development in typically developing infants and infants at risk of cerebral palsy?

BackgroundIn typical development, postural adjustments during reaching change in the second half of infancy, including increasing rates of direction-specific adjustments. These changes are absent or different in infants at risk of cerebral palsy (CP). To discover whether these changes are related to acquisition of independent walking, we studied postural adjustments during reaching in infants before and after they learned to walk.MethodsTen typically developing (TD) infants and 11 infants at very high risk (VHR) of CP were assessed before and after they learned to walk. Reaching movements were elicited during supported sitting, while surface electromyography was recorded of arm, neck, and trunk muscles. Percentages of direction-specific adjustments (first level of control), and recruitment patterns and anticipatory activation (second level of control) were calculated.ResultsIn both groups, postural adjustments during reaching were similar before and after acquisition of independent walking. Direction-specificity increased with age in typically developing infants but not in VHR-infants.ConclusionIncreasing age rather than the transition to independent walking is associated with increasing direction-specificity of TD-infants during reaching while sitting, while infants at very high risk of CP show no increase in direction-specificity, suggesting that they gradually grow into a postural deficit.     

Age-related changes in visual pseudoneglect

Pseudoneglect is a slight but consistent leftward attentional bias commonly observed in healthy young populations, purportedly explained by right hemispheric dominance. It has been suggested that normal aging might be associated with a decline of the right hemisphere. According to this hypothesis, a few studies have shown that elderly tend to exhibit a rightward attentional bias in line bisection. In the present study, we tested this hypothesis in young and older participants using a perceptual landmark task. Results yield evidence for an age-related shift, from a strong attentional leftward bias in young adults toward a suppressed or even a reversed bias in the elderly. Right hemisphere impairment coupled to a left hemispheric compensation might explain the perceptual shift observed in older adults. However, a decline in corpus callosum function cannot be excluded. Alternatively, these results may be in agreement with the hypothesis of an age-related specific inhibition of return dysfunction, an overt attentional orienting mechanism, and/or a decrease of dopamine.     

Resource-dependent effects during sex categorization

The limited capacity of face perception resources in the left cerebral hemisphere was examined using a sex categorization task. One study tested the hypothesis that sex categorization is impeded whenever feature extraction resources in the left hemisphere are simultaneously being utilized by another task. This hypothesis was tested by presenting prime faces for either 32 ms or 320 ms to either the left or right visual-field just before centrally presented target faces were categorized by sex. Results showed that sex categorization was slower after prime faces were presented for 32 ms in the right visual-field compared to the left visual-field. This difference was not found after the 320 ms prime length. The results are interpreted in the context of a neurocognitive model of social perception and suggest that efficient sex categorization depends, in part, on the availability of facial feature extraction resources in the left hemisphere.     

Does degree of asymmetry relate to performance? An investigation of word recognition and reading in consistent and mixed handers

Is it advantageous to be strongly lateralized? The current study investigated this question by examining the relationship between visual field asymmetries for lexical tasks and reading performance in a sample of 200 young adults. Larger visual field asymmetries were associated with better reading performance, but this relationship was obtained primarily in those with strong and consistent hand preferences. Among mixed handers, variation in visual field asymmetry accounted for little or no variance in reading skill. In addition, correlations between visual field asymmetry and reading performance were observed for word recognition tasks, but not for tasks requiring controlled semantic retrieval. The results are consistent with the idea that consistent and mixed handers may represent differing neurobehavioral populations. Because greater lateralization was associated with better reading skill only for consistent handers, reduced behavioral asymmetry cannot be assumed to be a risk factor for reading dysfunction in the population as a whole.     

冠脉介入术支架内血栓的危险因素和预防策略

支架内血栓形成是经皮冠状动脉介入治疗罕见但极为严重的并发症,常导致患者心肌梗死和死亡。其危险因素包括抗血小板治疗、支架因素、介入操作因素、患者及病变因素等。预防的关键在于积极防治上述危险因素,主要包括延长抗血小板治疗疗程、选择合适的支架类型和操作技术、开发新型支架和抗血小板药物,同时注意冠心病二级预防。     

Gradual increase of perturbation load induces a longer retention of locomotor adaptation in children with cerebral palsy

The goal of this study is to determine whether the size and the variability of error have an impact on the retention of locomotor adaptation in children with cerebral palsy (CP). Eleven children with CP, aged 7–16 years old, were recruited to participate in this study. Three types of force perturbations (i.e., abrupt, gradual and noisy loads) were applied to the right leg above the ankle starting from late stance to mid-swing in three test sessions while the subject walked on a treadmill. Spatial-temporal gait parameters were recorded using a custom designed 3D position sensor during treadmill walking. We observed that children with CP adapted to the resistance force perturbation and showed an aftereffect consisting of increased step length after load release. Further, we observed a longer retention of the aftereffect for the condition with a gradual load than that with an abrupt load. Results from this study suggested that the size of error might have an impact on the retention of motor adaptation in children with CP with a longer retention of motor adaptation for the condition with a small size of error than that with a large error. In addition, enhanced variability of error seems facilitate motor learning during treadmill training. Results from this study may be used for the development of force perturbation based training paradigms for improving walking function in children with CP.     

Embolie gazeuse cérébrale lors d’une séance d’hémodialyse : aspects médico-légaux : à propos d’une affaire judiciaire

Air embolism is a serious iatrogenic event, concerning many invasive medical therapies. It is a rare but life-threatening adverse event. We report a case of a cerebral air embolism occurring during a renal replacement therapy. We report the case of a court case analyzed in the Department of Legal Medicine of Farhat Hached University Hospital in Sousse, Tunisia, related to a cerebral gas embolism occurring during a session of renal replacement therapy. Then we discuss the medical liability of the medical team involved in this act. Through a draft organic law (law No. 41/2019 on patients’ rights and medical liability), Tunisian jurisprudence aims at resolving legal claims in the field of medical liability by providing more opportunities for an amicable solution and by guaranteeing an adequate and quick compensation of the damage suffered.     

Dynamic touch is affected in children with cerebral palsy

Children with developmental disorders such as cerebral palsy have limited opportunities for effortful interactions with objects and tools. The goal of the study was to investigate whether children with cerebral palsy have deficits in their ability to perceive object length by dynamic touch when compared to typically developing children. Fourteen children with typical development and 12 children with cerebral palsy were asked to report the length of hand-held rods after wielding them out of sight. Multilevel regression models indicated that I₁ (maximum principal moment of inertia) was a significant predictor of perceived length – L_P (p < .0001). The effect of I₁ on L_P was significantly different among children (p = .001) and the presence of cerebral palsy (group factor) partially explained such variance (p = .002). In addition, accuracy and reliability of the length judgments made by children with cerebral palsy were significantly lower than the typically developing children (p < .05). Theoretical and clinical implications of these results were identified and discussed.     

Functional cerebral changes in multiple sclerosis patients during an autobiographical memory test

Our aim was to investigate the functional underpinnings of autobiographical memory (AM) impairment in multiple sclerosis (MS) patients. To that end, 18 patients and 18 controls underwent the autobiographical interview (AI). Subsequently, the 36 participants underwent a functional magnetic resonance imaging (fMRI) session designed to assess the construction and elaboration of AMs. A categorical control task was also presented. Patients were trained in the fMRI procedure to optimise the procedural aspects accompanying the task itself. Although the patients obtained significantly poorer AI scores (p < .001), their performance on the easier AM fMRI task was efficiently carried out, allowing relevant comparisons with healthy controls. Relatively to healthy controls, the patients showed increased and bilateral cerebral activations (p < .005) during the construction and elaboration phases. The prefrontal, temporal and posterior cerebral region activations were located within the core network sustaining AM, with the bilateral prefrontal region being centrally involved. The parametric neural responses to the difficulty of access and amount of details of memories were also significantly different for the two groups, with the right hippocampal region showing a particularly increased recruitment (p < .005). The findings suggested the presence of functional cerebral changes during AM performance and supported the presence of AM retrieval deficit in MS patients.