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Hand Preference (hand + preference)

Distribution by Scientific Domains

Life Sciences	50%
Medical Sciences	21%

Selected Abstracts

Prevalence and handedness correlates of traumatic injuries to the permanent incisors in 13,17-year-old adolescents in Erzurum, Turkey

DENTAL TRAUMATOLOGY, Issue 5 2003
Varol Canakci
Abstract ,,,The objectives of the present study were to explore the relationship between dental trauma and handedness, and to assess the prevalence of traumatic injuries to the permanent incisors of 13,17-year-old patients, seeking treatment for various dental conditions in Erzurum, Turkey. A questionnaire focusing on handedness was administered to these patients. Handedness was assessed by the Edinburgh Handedness Inventory (Oldfield, 1971). Hand preference was divided into two classes for convenience in data analysis: (i) right-handers (GSc from 80 to 100); and (ii) left-handers (GSc from ,80 to ,100). This study included the 13,17-year-old group patients who had GSc as described above. Thus, the present study was carried out on 2180 (1252 male and 928 female, with a mean age of 14.9 years) out of 2392 patients. The clinical examinations and radiographic assessments were performed in full-designed dental chairs. Preliminary analysis showed no differences in rates of handedness with respect to sex and age. Overall, 10.4% of the patients were left-handers. A total of 292 (13.4%) of 2180 patients examined had one or more traumatized permanent incisors. The proportion of dental trauma was significantly higher in males than in females, 17.41% in males as compared to 7.97% in females; and ratio of the affected males to females was about 2.18. Sex difference in the prevalence of traumatized permanent incisors was statistically significant (P < 0.001). That is, males had a significantly higher risk of dental trauma than females (P < 0.001; odds ratio: 2.49; 95% confidence interval (CI) 1.88, 3.23). There was a higher level of traumatized permanent incisors among left-handers than among right-handers. 28.3% of left-handers and 11.7% of right-handers had dental trauma. This difference in the prevalence of traumatized permanent incisors for handedness was statistically significant (P < 0.001). Indeed, left-handers had a significantly higher risk on dental trauma than right-handers (P < 0.001; odds ratio: 3.09; 95% CI 2.23, 4.29). The primary causative factor in the occurrence of trauma was the fall (27.7%). Then came violence and fight as the second most frequent cause of trauma (24%), followed by sports injury (18.8%). Trauma resulting from collisions and traffic accidents were accounted as 13.7 and 11.3% of all cases, respectively. The other causes were 4.5%. In conclusion, the present study suggests that left-handed adolescents have more frequent permanent incisor tooth trauma than right-handed adolescents. Left-handedness, therefore, appears to be a risk factor for trauma in 13,17-year-old adolescents. [source]

Hand preference in unimanual and bimanual tasks and postural effect on manual laterality in captive red-capped mangabeys (Cercocebus torquatus torquatus)

AMERICAN JOURNAL OF PRIMATOLOGY, Issue 5 2006
C. Blois-Heulin
Abstract Hand preference in 11 captive red-capped mangabeys (Cercocebus torquatus torquatus) was examined under different conditions: a free situation during spontaneous food processing, three different postural conditions (brachiating, and bipedal and tripedal standing), and a situation involving bimanual processing. Generally, individual laterality was found regardless of the task and behavior involved. However, the number of monkeys with hand preferences and the strength of the preference increased with the complexity of the tasks. The monkeys exhibited a significantly higher and positive mean manual preference index (HI) when they were hanging than when they were quadrupedal or sitting. The strength of manual preference (ABS-HI) was in turn higher when the monkeys were hanging or bipedal than when they were quadrupedal. The strength of manual preference was higher for both the bimanual and experimental tasks than for unimanual tasks and spontaneous activities. Although our sample was too small to allow us to make any generalizations concerning lateral preferences in red-capped mangabeys, we propose some hypotheses about the influence of posture stability and task complexity. Am. J. Primatol. 68:1,16, 2006. © 2006 Wiley-Liss, Inc. [source]

Weak hand preference in children with down syndrome is associated with language deficits

DEVELOPMENTAL PSYCHOBIOLOGY, Issue 3 2008
M. A. Groen
Abstract This study explores associations between language ability and hand preference in children with Down syndrome. Compared to typically developing children of the same age, children with Down syndrome showed weaker hand preference, were less consistent in the hand they used and also less willing to reach to extreme positions in contralateral space. Within the group of children with Down syndrome, those who showed a stronger or more consistent hand preference had better language and memory skills. This association could not be explained by differences in non-verbal cognitive ability or hearing loss. These findings are discussed within the theory of neurolinguistic development proposed by Locke [Locke (1997). Brain & Language, 58, 265,326]. © 2008 Wiley Periodicals, Inc. Dev Psychobiol 50: 242,250, 2008. [source]

Cerebral dominance and schizophrenia-spectrum disorders in adults with intellectual disability

JOURNAL OF INTELLECTUAL DISABILITY RESEARCH, Issue 6 2000
D. Rowe
Abstract Studies of the general population without intellectual disability have suggested an association between atypical handedness and schizophrenia-spectrum disorders (SSDs). Mixed handedness is taken as an index of diminished cerebral dominance or laterality. The present study addressed the question of whether such findings extend to the neurodevelopmentally ,at risk' population of adults with intellectual disability and SSDs compared with appropriate controls. Fourteen patients with a dual diagnosis of intellectual disability and SSD were compared with 14 controls with intellectual disability alone. Assessments of self-reported hand preference and relative hand skill were completed. Self-report of hand preference revealed highly significantly greater mixed-handedness in the SSD group. Furthermore, relative hand skill performance was significantly diminished for the dominant hand. The discrepancy between dominant and non-dominant hand functioning was lower in the SSD group and this association was highly significant. The results of the present study support the usefulness of such detailed laterality assessment in this population. Mixed laterality, over and above that of the population with general intellectual disability and developmental disorder, was associated with SSD. These results are consistent with the neurodevelopmental hypothesis of schizophrenia and its cognitive neuropsychiatric/neuropsychological sequelae. [source]

Laterality in semi-free-ranging black and white ruffed lemurs (Varecia variegata variegata): head-tilt correlates with hand use during feeding

AMERICAN JOURNAL OF PRIMATOLOGY, Issue 12 2009
Eliza 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 Africa

AMERICAN JOURNAL OF PRIMATOLOGY, Issue 1 2009
Tatyana 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]

Planar Asymmetry Tips the Phonological Playground and Environment Raises the Bar

CHILD DEVELOPMENT, Issue 4 2001
Mark A. Eckert
Reading readiness varies as a function of family and environmental variables. This study of 11-year-old children (N=39) was designed to determine if there was an additional or interactive contribution of brain structure. Evidence is presented that both environmental and biological variables predict phonological development. Temporal lobe (planar) asymmetry, hand preference, family history of reading disability, and SES explained over half of the variance in phonological and verbal performance. The results demonstrate a linear association between cerebral organization and phonological skill within socioeconomic groups. These data provide concrete evidence to support the commonly held assumption that both environmental and biological factors are independent determinants of a child's ability to process linguistic information. [source]

Brief communication: Captive gorillas are right-handed for bimanual feeding

AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY, Issue 4 2010
Adrien 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]

Laterality in semi-free-ranging black and white ruffed lemurs (Varecia variegata variegata): head-tilt correlates with hand use during feeding

Hand preference in unimanual and bimanual tasks and postural effect on manual laterality in captive red-capped mangabeys (Cercocebus torquatus torquatus)