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Hand Use (hand + use)
Selected AbstractsRett Syndrome and long-term disorder profileJOURNAL OF INTELLECTUAL DISABILITY RESEARCH, Issue 10 2008E. Smeets Since the identification of mutations in MECP2 in females with clinical Rett syndrome, numerous efforts have been made to understand phenotype-genotype relationships. Most of these studies were conducted by examining the type and localization of these mutations in the gene in relation to clinical severity. It seemed unsatisfactory, in view of the age range and variable severity, to look only at the type and localization of the mutation in MECP2 in trying to establish a phenotype/genotype relationship. Describing each RTT individual after a long term follow up and grouping females with the same disorder history and same MECP2 mutation is therefore appropriate. Complete clinical and molecular data were obtained on 103 females. The guidelines for reporting manifestations common in Rett syndrome were used in the evaluation of clinical severity. The individuals were grouped according to similar disorder profiles on long-term follow up. In a cohort of 103 females clinically diagnosed with Rett syndrome, 91 had a detectable MECP2 mutation. 60% still sit and walk. Hand use is preserved or reduced in 44%. Speech has been lost in the majority (87%). Epilepsy was problematic in about 30%. Scoliosis, severe kyphosis or a combination of both was present in 27%, needing surgery in 13%. Description of the profile of the disorder and long-term clinical history facilitated the grouping of females with the same MECP2 mutation and a similar history. This approach will contribute more to the understanding of the ongoing pathology in Rett syndrome relative to the specific character of the involved MECP2 mutation. Some examples of these disorder profiles will be discussed. [source] Neuropathology of Rett syndromeDEVELOPMENTAL DISABILITIES RESEARCH REVIEW, Issue 2 2002Dawna Duncan Armstrong Abstract Rett Syndrome is unlike any other pediatric neurologic disease, and its clinical-pathologic correlation can not be defined with standard histology techniques. Based on hypotheses suggested by careful clinical observations, the nervous system of the Rett child has been explored utilizing morphometry, golgi preparations, computerized tomography, magnetic resonance imaging, chemistry, immunocytochemistry, autoradiography, and molecular biologic techniques. From these many perspectives we conclude that Rett syndrome is not a typical degenerative disorder, storage disorder, nor the result of gross malformation, infectious or neoplastic processes. There remain regions of the brain that have not been studied in detail but the available data suggest that the neuropathology of Rett syndrome can be summarized as follows: the Rett brain is small for the age and the height of the patient; it does not become progressively smaller over three to four decades; it has small dendritic trees in pyramidal neurons of layers III and V in selected lobes (frontal, motor, and temporal); it has small neurons with an increased neuronal packing density; it has an immature expression of microtubular protein-2 and cyclooxygenase; it exhibits a changing pattern of neurotransmitter receptors with an apparent reduction in many neurotransmitters, possibly contributing to some symptomatology. A mutation in Mecp2 causes this unique disorder of brain development. Neuronal mosaicism for normal and mutated Mecp2 produces a consistent phenotype in the classic female patient and a small brain with some preserved islands of function, but with an inability to support hand use and speech. This paper summarizes our current observations about neuropathology of Rett syndrome. MRDD Research Reviews 2002;8:72,76. © 2002 Wiley-Liss, Inc. [source] Longitudinal development of hand function in children with unilateral cerebral palsyDEVELOPMENTAL MEDICINE & CHILD NEUROLOGY, Issue 4 2010MARIE HOLMEFUR PHD REG OT Aim The aim of this study was to describe how the usefulness of the hemiplegic hand develops in children with unilateral cerebral palsy (CP) aged between 18 months and 8 years. Method A prospective longitudinal study of 43 children (22 males, 21 females) with unilateral CP was conducted. Inclusion age was 18 months to 5 years 4 months (mean 2y 8mo [SD 1y 1mo]). Children were assessed with the Assisting Hand Assessment (AHA) 3 to 11 times per child over a mean period of 4 years 6 months. Two models were used for grouping children: by AHA score at 18 months and by Manual Ability Classification System (MACS) levels. Estimated average motor development curves were fitted with a nonlinear mixed-effects model. Results Children with a high AHA score (high ability level) at 18 months reached a significantly higher ability level and at a higher progression rate than children with a low 18-month AHA score. Limits of development differed between the three MACS levels. Interpretation Results indicate that the AHA score at 18 months can be used to discuss future development of affected hand use in bimanual tasks in children with unilateral CP. [source] Findings from a multidisciplinary clinical case series of females with Rett syndromeDEVELOPMENTAL MEDICINE & CHILD NEUROLOGY, Issue 5 2003Hilary Cass BSc FRCPCH Systematic data from a multidisciplinary clinical assessment of a large series of females with Rett syndrome (RS; n=87) is presented. Participants' ages ranged from 2 years 1 month to 44 years 10 months. Areas assessed included oromotor skills, feeding problems, growth, breathing abnormalities, mobility, postural abnormalities and joint deformities, epilepsy, hand use and stereotypies, self-care, and cognitive and communication skills. Many previously reported trends in the presentation of RS over time were confirmed, notably the increasingly poor growth and near pervasiveness of fixed joint deformities and scoliosis in adulthood. In contrast, there was a slight trend towards improved autonomic function in adulthood, whereas feeding difficulties increased into middle childhood and then reached a plateau. Improvements in mobility into adolescence were followed by a decline in those skills in adulthood. Levels of dependency were high, confirming findings from previous studies. Despite the presence of repetitive hand movements, a range of hand-use skills was seen in individuals of all ages. Cognitive and communication skills were limited, but there was little evidence of deterioration of these abilities with age. These findings confirm that RS is not a degenerative condition and indicate that intervention and support to maintain and increase motor skills, daily living skills, and cognitive and communicative functioning are appropriate targets for individuals with RS. [source] The neural control of bimanual movements in the elderly: Brain regions exhibiting age-related increases in activity, frequency-induced neural modulation, and task-specific compensatory recruitmentHUMAN BRAIN MAPPING, Issue 8 2010Daniel J. Goble Abstract Coordinated hand use is an essential component of many activities of daily living. Although previous studies have demonstrated age-related behavioral deficits in bimanual tasks, studies that assessed the neural basis underlying such declines in function do not exist. In this fMRI study, 16 old and 16 young healthy adults performed bimanual movements varying in coordination complexity (i.e., in-phase, antiphase) and movement frequency (i.e., 45, 60, 75, 90% of critical antiphase speed) demands. Difficulty was normalized on an individual subject basis leading to group performances (measured by phase accuracy/stability) that were matched for young and old subjects. Despite lower overall movement frequency, the old group "overactivated" brain areas compared with the young adults. These regions included the supplementary motor area, higher order feedback processing areas, and regions typically ascribed to cognitive functions (e.g., inferior parietal cortex/dorsolateral prefrontal cortex). Further, age-related increases in activity in the supplementary motor area and left secondary somatosensory cortex showed positive correlations with coordinative ability in the more complex antiphase task, suggesting a compensation mechanism. Lastly, for both old and young subjects, similar modulation of neural activity was seen with increased movement frequency. Overall, these findings demonstrate for the first time that bimanual movements require greater neural resources for old adults in order to match the level of performance seen in younger subjects. Nevertheless, this increase in neural activity does not preclude frequency-induced neural modulations as a function of increased task demand in the elderly. Hum Brain Mapp, 2010. © 2010 Wiley-Liss, Inc. [source] Brief communication: Captive gorillas are right-handed for bimanual feedingAMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY, Issue 4 2010Adrien Meguerditchian Abstract Predominance of right-handedness has historically been considered as a hallmark of human evolution. Whether nonhuman primates exhibit population-level manual bias remains a controversial topic. Here, we investigated the hypothesis that bimanual coordinated activities may be a key-behavior in our ancestors for the emergence and evolution of human population-level right-handedness. To this end, we collected data on hand preferences in 35 captive gorillas (Gorilla gorilla) during simple unimanual reaching and for bimanual coordinated feeding. Unimanual reaching consisted of grasping food on the ground, while bimanual feeding consisted of using one hand for holding a food and processing the food item by the opposite hand. No population-level manual bias was found for unimanual actions but, in contrast, gorillas exhibited a significant population-level right-handedness for the bimanual actions. Moreover, the degree of right-handedness for bimanual feeding exceeds any other known reports of hand use in primates, suggesting that lateralization for bimanual feeding is robust in captive gorillas. The collective evidence is discussed in the context of potential continuity of handedness between human and nonhuman primates. Am J Phys Anthropol 2010. © 2009 Wiley-Liss, Inc. [source] Multiple measures of laterality in Garnett's bushbaby (Otolemur garnettii)AMERICAN JOURNAL OF PRIMATOLOGY, Issue 3 2010David B. Hanbury Abstract Behavioral laterality, a common measure of hemispheric specialization of the brain, has been examined in multiple tasks across several species of prosimian primates; however, there is inconsistency among findings between and within species that leaves many questions about laterality unanswered. Most studies have employed few measures of laterality, most commonly handedness. This study examined multiple measures of laterality within subjects in 17 captive-born Garnett's bushbabies (Otolemur garnettii) to assess the consistency of lateralized behaviors and to examine possible influences such as age, posture, novelty, and arousal to elucidate the relations between direction and strength of laterality. We measured reaching, turning bias, scent marking, tail wrapping, leading foot, side-of-mouth preference, and hand use in prey capture. Because autonomic arousal has been invoked as a determinant of strength of lateralization, we included multiple tasks that would allow us to test this hypothesis. All subjects were significantly lateralized on simple reaching tasks (P<0.01) and tail wrapping (P<0.01). Moreover, the number of animals lateralized on turning (P<0.01), leading limb (P<0.05), mouth use (P<0.01), and prey capture (P<0.01) was greater than would be expected by chance alone. There was consistency in the strength and direction of hand biases across different postures. Tasks requiring hand use were more strongly lateralized than tasks not involving hand use (P<0.001). The data do not support the assumption that arousal (as subjectively categorized) or novelty strengthens lateralized responding. The results of this study are discussed in terms of the effects of arousal, posture, and age on lateralized behavior. Am. J. Primatol. 72:206,216, 2010. © 2009 Wiley-Liss, Inc. [source] Laterality in semi-free-ranging black and white ruffed lemurs (Varecia variegata variegata): head-tilt correlates with hand use during feedingAMERICAN JOURNAL OF PRIMATOLOGY, Issue 12 2009Eliza L. Nelson Abstract Previous studies in human and chimpanzee infants have identified a predictive relationship between early rightward head orientation and later right hand use. Data from lemurs suggest a leftward bias in hand preference, but there are no data on head positioning. The purpose of this study was to examine the relationship between head and hand preferences in the black and white ruffed lemur (Varecia variegata variegata). Ruffed lemurs rotate the head vertically during chewing in a behavior called head-tilting. Frequency of head-tilting and bouts of unimanual hand use were measured during normal feeding in a semi-free-ranging population of lemurs. Subjects were provisioned at feeding platforms twice daily with fresh fruits, vegetables, and other food items. Sampling was spontaneous and all observations were videotaped. No group-level bias was found for head-tilting, but a left hand bias emerged for hand use. A positive relationship was found between direction of head-tilting preference and direction of hand use preference such that left head-tilts increased as left hand use increased. Furthermore, left head-tilts increased as the degree of hand preference lateralization increased. When the hand used to bring food to the mouth just before head-tilting was examined, there was a strong bias for the left hand to precede left head-tilts. For right head-tilts, however, lemurs were equally likely to use either hand before head-tilting. Overall a strong relationship was found between the left hand and left head-tilting in black and white ruffed lemurs, suggesting a common link between these behaviors. However, the direction of bias was different from that seen in human and chimpanzee studies. Additional studies on patterns of laterality would be informative for understanding how laterality has changed across the primate order and the adaptive significance of laterality in primates. Am. J. Primatol. 71:1032,1040, 2009. © 2009 Wiley-Liss, Inc. [source] Laterality in hand use across four tool-use behaviors among the wild chimpanzees of Bossou, Guinea, West AfricaAMERICAN JOURNAL OF PRIMATOLOGY, Issue 1 2009Tatyana Humle Abstract Population-level right handedness is a human universal, whose evolutionary origins are the source of considerable empirical and theoretical debate. Although our closest neighbor, the chimpanzee, shows some evidence for population-level handedness in captivity, there is little evidence from the wild. Tool-use measures of hand use in chimpanzees have yielded a great deal of variation in directionality and strength in hand preference, which still remains largely unexplored and unexplained. Data on five measures of hand use across four tool-use skills,ant-dipping, algae-scooping, pestle-pounding and nut-cracking,among the wild chimpanzees of Bossou, Guinea, West Africa, are presented here. This study aims to explore age- and sex-class effects, as well as the influence of task motor, cognitive and haptic demands, on the strength and directionality of hand preference within and across all five measures of hand use. Although there was no age- or sex-class effect on the directionality of hand preference, immature ,10 years old tended to be less lateralized than adults, especially adult females. Nut-cracking, the most cognitively complex of the four behaviors and the only one requiring complementary coordination of both hands, yielded the greatest strength in hand use with all adults expressing exclusive use of one hand over the other, without overall significant directional preference. The least lateralized behavior was pestle-pounding, which required bimanual coordination, but also imposed constraints owing to fatigue. It emerged that only the most hazardous tool use, i.e. ant-dipping, and the sole haptic task, i.e. the extraction by hand of crushed oil-palm heart, were laterally biased and both to the right. Shared motor or grip patterns in tool-use skills failed to reveal any specialization in hand use at the individual level. Finally, Bossou chimpanzees demonstrated a tendency for a population-level right-hand use. Am. J. Primatol. 71:40,48, 2009. © 2008 Wiley-Liss, Inc. [source] Radiological evaluation of the morphological changes of root canals shaped with ProTaperÔ for hand use and the ProTaperÔ and RaCeÔ rotary instrumentsAUSTRALIAN ENDODONTIC JOURNAL, Issue 3 2008Carlos M. Aguiar dds Abstract This study evaluated, by means of the radiography examination, the occurrence of deviations in the apical third of root canals shaped with hand and rotary instruments. Sixty mandibular human molars were divided into three groups. The root canals in group 1 were instrumented with ProTaperÔ (Dentsply/Maillefer, Ballaigues, Switzerland) for hand use, group 2 with ProTaperÔ and group 3 with RaCeÔ. The images obtained by double superimposition of the pre- and postoperative radiographs were evaluated by two endodontists with the aid of a magnifier-viewer and a fivefold magnifier. Statistical analysis was performed using the Fisher-Freeman-Halton. The instrumentation using the ProTaperÔ for hand use showed 25% of the canals with a deviation in the apical third, as did the ProTaperÔ, while the corresponding figure for the RaCeÔ (FKG Dentaire, La-Chaux-de-Fonds, Switzerland) was 20%, but these results were not statistically significant. There was no correlation between the occurrence of deviations in the apical third and the systems used. [source] | |||||||||||||