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PubMedDate not supplied

Patterns of joint distribution in hand osteoarthritis: contribution of age, sex, and handedness.

The most frequent site of osteoarthritis (OA) is the hands, but the pattern of hand OA development remains controversial. Understanding these patterns may assist in evaluating biological aging, determining etiology, and proposing ways of preventing hand OA. We investigated the pattern distribution of OA in hands and the influences of age, sex, and handedness on its development. The study population was comprised of Chuvashians (660 males age 18-89 years and 585 females age 18-90 years). OA development was evaluated for 15 joints of each hand according to the Kellgren and Lawrence grading scheme. Statistical analyses included Pearson correlation, cluster analysis, MANCOVA, and linear and polynomial regression. OA changes first appeared in subjects <30 years of age. Metacarpophalangeal (MP) joints underwent the first OA changes until the sixth decade, when the row of distal interphalangeal (DIP) joints became most affected. Cluster analysis showed that symmetry was the most common pattern of interrelationship between rows of joints. The best-fitting and most parsimonious model of age-related pattern of hand OA was the polynomial two-interval linear model. It showed a higher rate of OA development during the relatively young ages, 32-34 years than later on. We found statistically significant differences between sexes only for the DIP (P = 0.019) and PIP (P = 0.011) rows of joints. Handedness had no influence on hand OA development.

Adolescent↗
PubMed2005

Hair whorls and handedness: informative phenotypic markers in nonsyndromic cleft lip with or without cleft palate (NS CL/P) cases and their unaffected relatives.

Cleft lip with or without cleft palate (CL/P) is a complex disorder with a range of phenotypic manifestations and a birth prevalence that varies by population (1/500-1/2,000). Investigators have postulated that CL/P cases may have abnormal brain development, citing structural brain differences, and cognitive impairments in affected individuals. Previously, increased levels of non-right handedness (NRH), a marker for abnormal brain lateralization, have also been demonstrated in CL/P cases. Atypical hair whorls, more direct markers of altered brain development, may be related to NRH. To date, neither hair whorl patterns nor their relationship to NRH have been studied in a CL/P population. In the current study, we investigate the hypothesis that altered brain development is part of the phenotypic spectrum of NS CL/P by assessing NRH and atypical hair whorls in CL/P families. The study population included 49 nonsyndromic CL/P cases and 116 of their unaffected relatives; 21.8% of the study population was NRH compared to the 10% population estimate (P < 0.0001). Counter-clockwise hair whorls (CCW) were found in 12.7% of all subjects compared to a population rate of 9.9 %. Of all subjects, 11% of the NRH individuals had CCW, which was similar to the frequency of CCW in right-handed individuals. Approximately 80% of the whorls were placed on either the right or center of the scalp. No significant associations were found between the type of cleft and handedness, hair whorl rotation, or placement. These results suggest that certain phenotypic markers of abnormal brain development may comprise part of the extended phenotype of orofacial clefting.

Abnormalities, Multiple↗
PubMed1995

Intertubercular sulcus of the humerus as an indicator of handedness and humeral length.

Measurements of the maximum width and depth of the intertubercular sulcus (ITS), angles of the medial and lateral walls with the floor of the ITS, as well as the length of the humerus in 100 right and 100 left matched, unpaired dry humeri of 100 adults were statistically analyzed. Since 90-95% of the general population is right handed, on the basis of altered size of the dimensions of the right ITS relative to the left, it is proposed that greater width and smaller angles of the medial and lateral walls of the ITS of one side are indicative of handedness on that side. Handedness can further be deduced by the presence of a < 50 degrees angle of the medial wall and of a supratubercular ridge of Meyer on that side. The length of the humerus correlated with the width and depth of the ITS (P < 0.001). Regression equations of the length of the humerus on width, depth, as well as width and depth of the ITS have been derived.

Adult↗
PubMed2004

Influence of object spatial location and task complexity on children's use of their preferred hand depending on their handedness consistency.

The goal of the present study was to compare the use of the preferred versus the nonpreferred hand in children performing two tasks of different levels of complexity, in various positions in space. Right-handed and left-handed consistent children were compared to their inconsistent counterparts. The results showed that the general tendency to use one's preferred hand to grasp an object is more or less pronounced depending on the object's spatial location and the task's complexity. The children used their preferred hand more often even when the object was presented contralaterally, and did so to a greater extent during the more complex task. Inconsistent-handers were more likely to shift to using their nonpreferred hand when the object was presented to this hand's side. Finally, we found that the influence of handedness consistency on hand use for the spatial positions varied with the complexity of the task. These results favor a view of handedness as a dynamic process in which motor preferences interact with task demand, probably through task-related attention.

Child↗
PubMed2005

Handedness and specific language impairment: a study of 6-year-old twins.

Handedness and language skills were assessed in 196 same-sex twin pairs (101 MZ and 95 DZ), who were selected from an epidemiological study of twins, so that children with risk of language impairment were over-represented. When assessed at 6 years of age, 83 children met criteria for specific language impairment (SLI), 32 had general developmental (GD) delay, and the remaining 277 were typically-developing (TD). Hand preference (HP) assessed by inventory did not distinguish SLI, TD, or GD groups. The quantification of hand preference (QHP) measure, which measures persistence of a HP when reaching across the midline, did show weaker HP in those with SLI compared to the other two groups. It is suggested that the QHP measure assesses developmental aspects of manual lateralization, and is sensitive to neurodevelopmental immaturity in SLI. Furthermore, genetic analysis showed that the QHP measure, unlike the handedness inventory, was significantly heritable.

Age Factors↗
PubMed1994

The GBG model: is there more to consider than handedness?

It is peculiar that Bryden and his colleagues admit to the inadequacy of handedness as an index for cerebral anomalous dominance and then attack a model of anomalous dominance using primarily handedness data. In reality, the GBG model (which was intended to be "a hypothesis and program for research," to quote the exact titles of the 1985 articles) is not nearly as narrow as Bryden's worldview. We present here the rest of the literature on the link between immune disorders and language disorders which Bryden et al. neglected and argue that the data are sufficient to have warranted a +2 in their evaluation. The strength of this link is worthy of further investigation, even though the hormonal mechanism proposed in the GBG model may be erroneous.

Animals↗
PubMed1997

Handedness and P300 from auditory stimuli.

The P3(00) event-related potential (ERP) was elicited in 20 left- and 20 right-handed normal young adult male subjects using a simple auditory stimulus discrimination task. P3 amplitude from the target stimuli was larger at anterior electrode sites for left- compared to right-handed subjects. P3 latency from the standard stimuli was shorter for left- compared to right-handers. The N1, P2, and N2 components generally demonstrated similar handedness effects. The relationship of ERP amplitude and handedness to anatomical variables and cognitive factors is discussed.

Adult↗
PubMed2000

Influences of handedness and gender on the grooved pegboard test.

We studied performance on the Grooved Pegboard Test upon repeated trials and transfer of training between the hands in the first trial. The classification of handedness was based on the writing hand. We employed three trials for each hand and two different protocols for the order in which the hands started the test. For the three trials combined, women were faster than men. From the first to the second trial, there was an improvement in performance for both sexes. Within the first trial, sex differences reached significance and the protocol interacted with handedness. In this trial, only left-handed men were found to benefit from previous opposite-hand performance. It is speculated that a larger corpus callosum in left-handed men allows for the greater transfer of training between the hands.

Adult↗
PubMed1996

Determination of DNA helical handedness by fluorescence resonance energy transfer.

Fluorescence resonance energy transfer (FRET) has been used to determine the helical handedness, twist and rise of different DNA conformations. The approach is based on the construction of a set of molecules consisting of two fused helical segments, one of which is in a known reference helical form. The duplexes are covalently labeled at one end with a donor and at the other with an acceptor. By systematically shifting the position of the junction while maintaining constant the total length in base-pairs, the variation in the efficiency of energy transfer can be shown to depend primarily and sensitively on the differences in helical twist and rise of the two constituent segments. If the latter have the same helical sense, one predicts a FRET signal that is a monotonic function of the junctional position. In contrast, a periodic function arises when two segments are of opposite handedness. The formalism includes explicit consideration of dye orientation (the dipole-dipole orientation factor kappa) and an implementation valid for single helix molecules, and introduces new functions of measured fluorescence signals for establishing the FRET efficiency. The method has been applied to a family of oligonucleotides forming hairpin duplexes containing an antiparallel-stranded (aps) d(m5C.G)m segment labeled at the 5' end with fluorescein (donor) and a second parallel- stranded d(A.T)N-m segment (psAt-DNA) labeled at the hairpin loop with the sulfoindocyanine dye Cy3. The segment lengths were in the range 4 to 12, but the total length N was maintained constant at 16. The d(m5C.G) sequence was chosen due to its capacity for adopting a B or a Z conformation at low and high concentrations of salt, respectively. The parallel-stranded d(A.T) sequence served as the second segment in order to determine the helical rise and twist of psAT-DNA, presumed to be right-handed from molecular modeling and a prior study of topologically constrained DNA. A Z-DNA/ps-DNA junction was created between the two segments by inducing a B-Z transition in d(m5C.G)m with MgCl2. The range of required salt concentration was established by circular dichroism measurements. FRET efficiency values of 0.38 to 0.41 were obtained for the oligonucleotides with the d(m5C.G) segment in the B conformation. In contrast, upon induction of the B-Z transition the FRET efficiency was a decreasing function of the d(m5C.G) content (0.38 to 0.28 for m = 6 to 12). Helical parameters were estimated from functional fits of the data, and were consistent with the known properties of B- and Z-DNAs and with the conclusion that psAT-DNA has a helical rise and twist close to that of B-DNA. The approach outlined here is not restricted to DNA but can be applied to other helical structures, e.g. RNA, proteins, and protein-nucleic acid complexes.

DNA↗
PubMed1996

Asymmetry in the human motor cortex and handedness.

Handedness is one of the most obvious functional asymmetries, but its relation to an anatomical asymmetry of the hand representation area in the motor cortex has not been demonstrated. This would be a crucial test for the hypothesis of structure-function correlation in cortical motor organization. Using magnetic resonance morphometry, we show for the first time that the depth of the central sulcus is related to handedness. In right-handers, the left central sulcus is deeper than the right, and vice versa in left-handers. Macrostructural asymmetry is complemented by a microstructural left-larger-than-right asymmetry in neuropil volume (i.e., tissue compartment containing dendrites, axons, and synapses) in Brodmann's area 4. These asymmetries suggest that hand preference is associated with increased connectivity (demonstrated by an increased neuropil compartment in left area 4) and an increased intrasulcal surface of the precentral gyrus in the dominant hemisphere.

Adult↗
PubMed1977

Handedness in autistic children.

A test of handedness in a sample of 20 autistic children and 25 normal children revealed marked differences. The frequency of non-right-handedness in normal children was 12%, whereas it was 65% in autistic children. The significance of this difference for the etiology of autism is discussed.

Autistic Disorder↗
PubMed1996

Bilateral skin temperature, handedness, and the biofeedback control of skin temperature.

There are differences in physiological variables when they are recorded from the left and right side of the body simultaneously. In some cases, handedness has been found to have a significant relationship to bilateral differences. The present study examined the relationship between handedness and baseline heart rate and skin temperature, as well as bilateral differences in skin temperature during visual and auditory biofeedback. Subjects were 32 college females, 24 right-handed and 8 left-handed. Recordings of heart rate and skin temperature from both the dominant and the nondominant hand were made during baseline and during the 10-min experimental session while subjects attempted to warm their dominant hand. Both groups showed significantly increased skin temperature during the experimental session. No prominent bilateral differences in skin temperature were found. These results do not support bilateral differences as a generalizable construct.

Adult↗
PubMed2001

Evidence for a dynamic-dominance hypothesis of handedness.

Handedness is a prominent behavioral phenomenon that emerges from asymmetrical neural organization of human motor systems. However, the aspects of motor performance that correspond to handedness remain largely undetermined. A recent study examining interlimb differences in coordination of reaching demonstrated dominant arm advantages in controlling limb segment inertial dynamics (Sainburg and Kalakanis 2000). Based on these findings, I now propose the dynamic-dominance hypothesis, which states that the essential factor that distinguishes dominant from nondominant arm performance is the facility governing the control of limb dynamics. The purpose of this study is to test two predictions of this hypothesis: 1) adaptation to novel intersegmental dynamics, requiring the development of new dynamic transforms, should be more effective for the dominant arm; 2) there should be no difference in adapting to visuomotor rotations performed with the dominant as compared with the nondominant arm. The latter prediction is based on the idea that visual information about target position is translated into an internal reference frame prior to transformation of the movement plan into dynamic properties, which reflect the forces required to produce movement. To test these predictions, dominant arm adaptation is compared to nondominant arm adaptation during exposure to novel inertial loads and to novel visuomotor rotations. The results indicate substantial interlimb differences in adaptation to novel inertial dynamics, but equivalent adaptation to novel visuomotor rotations. Inverse dynamic analysis revealed better coordination of dominant arm muscle torques across both shoulder and elbow joints, as compared with nondominant arm muscle torques. As a result, dominant arm movements were produced with a fraction of the mean squared muscle torque computed for nondominant arm movements made at similar speeds. These results support the dynamic-dominance hypothesis, indicating that interlimb asymmetries in control arise downstream to visuomotor transformations, when dynamic variables that correspond to the forces required for motion are specified.

Adaptation, Physiological↗
PubMed2002

Handedness and language cerebral lateralization.

Repetitive transcranial magnetic stimulation (rTMS) induces lateralized speech arrest consistent with cerebral dominance for language. Studies of language cerebral dominance in differently handed healthy subjects have been limited. Using a focal magnetic coil, we examined the degree of consistency between handedness as evaluated by the Stanley Coren Score and hemispheric dominance for language as determined by rTMS in 25 right- and 25 left-handed medical students. They were categorized according to the score into 24 strongly right-handed, 1 moderately right-handed, 19 strongly left-handed, 3 moderately left-handed and 3 ambidextrous (equally-handed). In the strongly right-handed subjects, left-sided language cerebral dominance was recorded in 87.5% of the subjects, and bilateral cerebral representation in 8.2%, and right-sided language cerebral dominance in 4.2%. In the strongly left-handed subjects, 73.7% had left-side language cerebral dominance, 15.8% had bilateral cerebral representation and 10.5% had right-side cerebral language dominance. In mixed handed subjects (moderately right, left and ambidextrous), bilateral cerebral representation was observed in 57% and left-side cerebral language dominance in 43%. There were 27 subjects who developed speech arrest at 140% of motor threshold, the others developed speech arrest at lower intensities. Speech lateralized to the left-side cerebral dominance in strongly right- and left-handed subjects, but bilateral cerebral representation was frequent in mixed handedness and right-sided cerebral dominance rarely occurred.

Adult↗
PubMed2005

Handedness, functional cerebral hemispheric lateralization, and cognition in male-to-female transsexuals receiving cross-sex hormone treatment.

This study examined the impact of sex hormones on functional cerebral hemispheric lateralization and cognition in a group of male-to-female transsexuals receiving cross-sex hormone therapy compared to eugonadal men with a male gender identity. Cerebral lateralization was measured with a handedness questionnaire and a visual-split-field paradigm and cognitive tests sensitive to sex hormone exposure (identical pictures, 3-D mental rotation, building memory) were also administered. Endocrine measures on the day of participation for transsexual and control subjects included total testosterone, free testosterone, estradiol, gonadotropins, and sex hormone binding globulin concentrations. Compared to controls, male-to-female transsexuals had elevated estradiol and sex hormone binding globulin concentrations and suppressed testosterone concentrations. Transsexual subjects showed a trend toward less exclusive right-handedness than controls. No group differences were observed on the visual-split-field or cognitive tasks. No direct associations were observed between endocrine measures and the laterality measures and cognitive performance. Previous observations of female-typical patterns in cerebral lateralization and cognitive performance in male-to-female transsexuals were not found in the current study.

Adult↗
PubMed2005

Handedness in children of schizophrenic parents: data from three high-risk studies.

This is the first report of data analyses from a consortium of longitudinal genetic-risk studies on offspring of schizophrenic parents (CLOSSER) who were followed from birth or mid-childhood to their early 20's or considerably older ages. Three of the CLOSSER studies provide data to enable us to address long-persisting questions in the schizophrenia literature concerning possible atypicality of hand dominance associated with the illness. Handedness, used as a proxy for cerebral lateralization, is a topic of considerable importance because of its potential to reveal mechanisms in the underlying pathophysiology of schizophrenia. We examine agreement among the CLOSSER studies with respect to possible deviance in handedness in subjects with schizophrenic parents (high-risk individuals) and specifically in those who have gone on to develop adult schizophrenia, compared with other subjects of these studies. Possible developmental delay in age at lateralization is also considered.

Adolescent↗
PubMed1990

Sex, handedness, and the morphometry of cerebral asymmetries on magnetic resonance imaging.

Cerebral morphometry of linear measurements and hemispheric, frontal, temporal and parietal areas on MRI of 104 normal adults was analyzed for sex and handedness and right-left differences. The right hemisphere was significantly larger across all groups, but the left frontal width and area was larger in left handers. MANOVA showed separate effects of hand and sex for linear measures; right-handers had larger right anterior frontal, and left parietal and occipital widths. Ratios of L - R/L + R eliminated sex differences related to overall brain size, however, a significant sex-by-hand interaction was shown by the parietal area ratios, indicating larger left side in right-handed males and left-handed females. A 3-dimensional 'torque' was postulated, where the upper and rostral portions of the hemispheres were larger on the right and the lower and caudal parts equal, or slightly larger on the left. The relationship of anatomical asymmetries, sex and handedness is multi-dimensional, and may explain some of the variability of normal cognitive functions and deficits after brain damage.

Adolescent↗