Tactile sensitivity of children: effects of frequency, masking, and the non-Pacinian I psychophysical channel

Tactile perception depends on the contributions of four psychophysical tactile channels mediated by four corresponding receptor systems. The sensitivity of the tactile channels is determined by detection thresholds that vary as a function of the stimulus frequency. It has been widely reported that tactile thresholds increase (i.e., sensitivity decreases) as a function of age. However, there is controversial evidence with regard to the progressive loss of sensitivity starting from childhood. In this study, the tactile thresholds of children (n=9, ages 7-11 years) were measured and compared with the thresholds of young adults (n=11, ages 21-27 years). The stimuli consisted of sinusoidal bursts of mechanical displacements, which were applied to the left index fingertips of the participants by using a cylindrical probe (base area=0.126 cm2) without a contactor surround. Absolute thresholds were measured at frequencies of 2, 10, 40, 100, 250, and 500 Hz without masking. The absolute thresholds decreased at high frequencies and were similar to data from the literature except for some discrepancy because of methodological differences. In addition, the threshold of the non-Pacinian I channel was measured at 40 Hz by elevating the thresholds of the Pacinian channel by forward masking. The effects of forward masking in children were similar to results in young adults. In conclusion, there were no significant differences between the tactile thresholds of children and those of young adults at key frequencies: 40 Hz for the Pacinian and non-Pacinian I channels and 250 Hz for the Pacinian channel. These findings contradict the hypothesis that there is gradual loss of tactile sensitivity starting from childhood to early adulthood. The loss of sensitivity due to aging probably is more abrupt and occurs at a later age.     

Developmental coordination disorder: exploration of a cerebellar hypothesis

This study explored the hypothesis of a specific cerebellar dysfunction in children with developmental coordination disorder (DCD): motor adaptation. The performance of a group of children with DCD (3 girls and 6 boys) was compared to that of a control group (5 girls and 6 boys) on a measure of motor adaptation, the prism adaptation test (PAT). Children were between 6 years 11 months and 11 years 10 months of age. Between-group differences were only found for PAT variables related to throwing accuracy, the DCD group being more variable and less accurate than the control group. While no between-group differences were found for the adaptation variables, individual data analysis revealed that only three children in the DCD group obtained normal adaptation variables. While these findings do not confirm the hypothesis of a cerebellar dysfunction, they also do not refute it. It is possible that the poor throwing accuracy of the DCD group masked the findings for some of the PAT variables. Further exploration of the function of the cerebellum among children with DCD is needed.     

Teachers' knowledge, misconceptions, and lacks concerning Attention Deficit Hyperactivity Disorder

This study was designed to analyze the knowledge, misconceptions, and lacks about Attention Deficit Hyperactivity Disorder (ADHD) in a sample of 193 teachers, as a replication of the study carried by Sciutto, Terjesen and Bender in 2000. Teachers completed the Knowledge of Attention Deficit Hyperactivity Disorder (KADDS) (Spanish version), adapted by the authors of this research, to measure knowledge of ADHD in three content areas: general knowledge, symptoms/diagnosis, and treatment. Results indicated an average of correct responses of 31.67, 63.88 and 40.46% in general knowledge, symptoms/diagnosis and treatment, respectively. Teachers displayed significantly more knowledge in the Symptoms/Diagnosis scale than in the other scales. Their knowledge correlated positively with: years of experience with hyperactive children, number of hyperactive pupils in their classrooms, and level of perceived self-efficacy. These findings are consistent with those obtained by Sciutto and colleagues.     

Career Nomadism and the Building of a Professional Identity in Female Immigrants

This article paints a picture of the professional integration of female immigrants in the Quebec City area, a city in which they are a small minority. Our main interest is the obstacles to their socio-professional integration. We attempt to shed light on this reality by giving an overview of the effects that disruptions in a woman’s career in general and an immigrant woman’s career in particular have in that, as workers in the so-called secondary sector, they are often the first affected by market polarization, our focus is on the intersection of identities that allow us to place the building of a professional identity in these women within its link to the adopted culture. Following is the representation of the obstacles faced by some of the women, approached in the framework of research on their professional integration, and the innovative identity-building strategies used to overcome these obstacles.     

Children's communication of the Linguistic Intergroup Bias and its impact upon cognitive inferences

The hypotheses that children use language strategically (e.g. as in the Linguistic Intergroup Bias) and with increasing strength with age were supported in an experiment with participants ranging in age from 8 to 19 years. In a second experiment, the impact of biased language use on participants' inferences was examined in a sample ranging in age from 5 to 11 years. It was shown for all age groups that participants' inferences were systematically influenced by the abstractness or concreteness of a message. The implications of these findings for the communication and transmission of stereotypes at an early age are discussed. Copyright © 1999 John Wiley & Sons, Ltd.     

Correction to: Bilingualism Is Associated with a Delayed Onset of Dementia but Not with a Lower Risk of Developing it: a Systematic Review with Meta-Analyses

Neuropsychology Review - The original version of this article unfortunately contained the following mistakes.     

Absence of Ankle Stiffening While Standing in Focus and Cognitive Task Conditions in Older Adults

Abstract

Research suggests that an external focus or cognitive task may improve postural control. Removing attention from movement production may promote automaticity, or the tasks may promote ankle stiffening. To investigate these two theories, twenty older adults stood while performing baseline standing, internal focus, external focus, and two cognitive tasks. Changes in postural control occurred in external focus and cognitive task conditions compared to baseline and internal focus, while no change occurred in cocontraction indices. This suggests that an external focus and cognitive task can improve postural control in older adults. Since no change occurred in cocontraction indices across conditions, this suggests that stiffening cannot explain these changes. Instead, changes could be due to automaticity of sway.