scholarly journals The incidence of left-handedness: a meta-analysis [1993]

2019 ◽  
Author(s):  
Ian Christopher McManus
Keyword(s):  
Sex Difference ◽  
Meta Analysis ◽  
Birth Cohorts ◽  
Future Studies ◽  
Left Handedness ◽  
Left Handed ◽  
Method Of Measurement ◽  
Males And Females ◽  
Older Subjects ◽  
Unpublished Manuscripts

A meta-analysis is reported of 88 studies, examining 100 study populations, in which the handedness of 284665 individuals has been assessed. The overall incidence of left-handedness was 7.78%. The incidence of left-handedness was not related to the method of measurement, or the length or number of response items included in inventories. Study populations with lower response rates and smaller study populations showed some evidence of higher incidences of left-handedness, presumably due to response biasses. There was no evidence that the incidence of left-handedness was related to the year of publication of studies; however the incidence of left-handedness was lower in older subjects and in those from earlier birth cohorts, the two effects not being statistically distinguishable.Information was available from 64 study populations concerning the incidence of left-handedness in males and females; overall 8.52% of males were left-handed compared with 6.69% of females, the male incidence being 27.4% higher than that in females. Although there was some suggestion that the sex difference was greater in larger studies, and in studies whose main purpose was not the study of handedness, these differences were not significant. It is concluded that the size of the sex difference is unrelated to any of the moderator variables we have studied.It was not possible to carry out a meta-analysis of degree of handedness due to wide-spread differences in the method of reporting of degree of handedness.We recommend that future studies of handedness should, as a minimum, use one of three standard methods of assessment, so that comparison of studies is facilitated. Note: This manuscript was originally prepared in 1993 but due to problems at a major journal, described briefly, was never eventually published. It has however been cited on a number of occasions, and has been available at https://www.ucl.ac.uk/medical-education/publications/unpublished-manuscripts/meta-analysis-of-handedness . A major meta-analysis of handedness in 2019 by another author has now been submitted which cites this manuscript, and therefore it needs to be available in a more archivable format.

Handedness in Two Generations

1983 ◽  
Vol 56 (3) ◽  
pp. 867-874 ◽  
Author(s):  
Lesley E. Tan
Keyword(s):  
Left Handedness ◽  
Left Handed ◽  
Item Questionnaire ◽  
Two Generations ◽  
Older Subjects ◽  
Younger Generation ◽  
Using Data

A 14-item questionnaire was administered to tertiary students and their families. The responses of the 508 subjects in the parental generation were compared with those of the 917 younger subjects. For every item significantly fewer older subjects gave left responses. The questionnaire identified more left-handers among older subjects than writing hand did, but as only 5.9% of these were classed as left-handed, compared with 11.8% of the younger generation, it seems unlikely that ascertainment was complete in the parental group. Using data from an additional 69 non-right-handers, item analyses indicated that writing and drawing were unsuitable items for older subjects and that, of the items tested, toothbrush and hammer use and pouring would be the best indicators of left-handedness.

scholarly journals DNA methylation in peripheral tissues and Left-handedness

2021 ◽  
Author(s):  
Veronika Odintsova ◽  
Matthew Sudermann ◽  
Fiona Hagenbeek ◽  
Doretta Caramaschi ◽  
Jouke-Jan Hottenga ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Meta Analysis ◽  
Longitudinal Analyses ◽  
Buccal Cells ◽  
Peripheral Tissues ◽  
Cpg Sites ◽  
Left Handedness ◽  
Left Handed ◽  
The Brain ◽  
Correlation Range

Abstract Handedness has low heritability and epigenetic mechanisms have been proposed as an etiological mechanism. To examine this hypothesis, we performed an epigenome-wide association study (EWAS) of left-handedness. In a meta-analysis of 3,914 adults of whole-blood DNA methylation, we observed that CpG sites located in proximity of handedness-associated genetic variants were more strongly associated with left-handedness than other CpG sites (P = 0.04), but did not identify any differentially methylated positions. We identified differentially methylated regions at 20q11.23 (P = 0.00004) and 2p25.1 (P = 0.03), which were less methylated in left-handed adults. In longitudinal analyses of DNA methylation in peripheral blood and buccal cells from children (N = 1,737), we observed moderately stable associations across age (correlation range [0.355–0.578]) but inconsistent across tissues (correlation range [-0.384-0.318]). We conclude that DNA methylation in peripheral tissues captures little of the variance in handedness. Future investigations should consider other more targeted sources of tissue, such as the brain.

Sex and Age Differences in Choice Behaviour: The Object–Person Dimension

Perception ◽  
1984 ◽  
Vol 13 (6) ◽  
pp. 719-724 ◽  
Author(s):  
Steve Jobson ◽  
John S Watson
Keyword(s):  
Older Adults ◽  
Sex Difference ◽  
Sex Role ◽  
Choice Situation ◽  
Social Stimuli ◽  
The Social ◽  
Males And Females ◽  
Older Subjects ◽  
Sex And Age Differences ◽  
Equal Interest

There is a popular belief that females are more socially oriented than males, while males are more nonsocially or object oriented than females. A 2 × 2 factorial design was employed to examine this, with independent variables of sex and age (young and older adults). The subjects were presented with six pairs of pictures, each consisting of an object and a person. Each presentation lasted 30 s; the time spent looking at each stimulus was taken as a measure of interest. The hypothesis that in this choice situation males and females would differ in their preference for object and person stimuli was confirmed. However, the sex difference was confined to young adults; older subjects of both sexes showed more (and equal) interest in the social stimuli than in the object stimuli. Masculinity and femininity scores on the Bem Sex Role Inventory showed some relationship with object–person preferences but failed to throw much light on the absence of a sex difference in older adults.

Frequency of Left-Handedness Among the Andhra Pradesh People

1975 ◽  
Vol 24 (1-2) ◽  
pp. 161-162 ◽  
Author(s):  
K. R. Dronamraju
Keyword(s):  
Andhra Pradesh ◽  
Tribal People ◽  
Left Handedness ◽  
Left Handed ◽  
Quantitative Studies ◽  
Aboriginal Populations ◽  
Males And Females ◽  
The Difference ◽  
Made In

The percentages of left-handed people among the males and females of Andhra Pradesh tribals in India were found to be 15.49 and 7.79, and in Hindus 6.9 and 4.65. The difference between the sexes among tribals is significant. The tribal people studied were Koya Doras, Sugalis {or Lambadis), and Konda Reddis. It is suggested that similar quantitative studies of left-handedness should be made in other tribal and aboriginal populations before they are culturally conditioned to right-handedness.

Senatorial signatures

2021 ◽  
pp. 1-7
Author(s):  
Nancy L. Segal ◽  
Francisca J. Niculae
Keyword(s):  
Statistical Power ◽  
Genetic Factors ◽  
Small Sample Size ◽  
Small Sample ◽  
Contributing Factors ◽  
Left Handedness ◽  
Left Handed ◽  
Males And Females ◽  
General Populations ◽  
Larger Sample

Abstract A greater frequency of left-handedness among males than females has been observed in general populations. Past studies have explained this difference with reference to males’ greater susceptibility to adverse birth events, while more recent studies have identified other contributing factors. On January 16, 2020, U.S. senators signed an oath to act impartially during the president’s impeachment trial. This televised event allowed direct comparison of the proportion of right-handedness and left-handedness in a professionally accomplished sample of males and females. As expected, no sex difference in the proportion of left-handed senators was found, although the small sample size offered low statistical power. Replicating this finding with a larger sample would support the view that left-handedness among select groups of males is linked to genetic factors.

A Meta-Analysis of Continuous Measure Sex Difference in Jealousy Studies

2009 ◽  
Author(s):  
Brad J. Sagarin ◽  
Amy L. Martin ◽  
Savia A. Coutinho ◽  
John E. Edlund
Keyword(s):  
Sex Difference ◽  
Meta Analysis ◽  
Continuous Measure

EVALUATION OF OCCURRENCE OF HYPERDONTIA IN NON-SYNDROMIC POPULATION FROM BIHAR REGION

2019 ◽  
Vol 3 (10) ◽  
Author(s):  
Dr. Minti Kumari ◽  
Dr. Madhuri Kumari ◽  
Dr Anurag Rai ◽  
Dr. Navin Kumar
Keyword(s):  
Panoramic Radiograph ◽  
Permanent Dentition ◽  
Dental Anomalies ◽  
Supernumerary Teeth ◽  
Panoramic Radiographs ◽  
Future Studies ◽  
Asian Populations ◽  
Males And Females ◽  
The Individual ◽  
Clinical Records

It is evident that hyperdontia is more common in the permanent dentition than in the primary. There is a considerable difference between males and females in the prevalence of these teeth in permanent dentition; hyperdontia is twice as common in males as in females. However, this approximation varies in terms of location, other associating syndromes that may be present, and the ethnicity of the individual. In terms of ethnicity, it can be seen that hyperdontia is in fact less common in Caucasian than in Asian populations. There is evidence to show that an individual is more likely to have hyperdontia if other members of their family also have the condition. Hence the present study was planned for evaluation of occurrence of hyperdontia in non-syndromic  population from Bihar Region. The present study was planned in Public Health Dentistry, Patna Dental College and Hospital, Patna, Bihar. Total 195 patients referred to Department of Dentistry were evaluated in the present study. Panoramic radiographs and clinical records of patients above the age of 18 years and without any syndromic features were selected for the study.  All the radiographs were examined for the presence of supernumerary teeth, their location, morphology, and number. Morphologically, teeth were classified as conical, tuberculate, supplemental, and odontoma. Early diagnosis of dental anomalies can prevent some esthetic, orthodontic, and periodontal problems, and knowledge of the prevalence and distribution of the anomalies may help clinicians to the detection of these anomalies at early stages. Our study evaluated the prevalence of selected dental anomalies; future studies should investigate the prevalence of dental anomalies of all types. Keywords: Hyperdontia, non-syndromic, panoramic radiograph, supernumerary teeth, etc.

scholarly journals Deep learning for cephalometric landmark detection: systematic review and meta-analysis

2021 ◽  
Author(s):  
Falk Schwendicke ◽  
Akhilanand Chaurasia ◽  
Lubaina Arsiwala ◽  
Jae-Hong Lee ◽  
Karim Elhennawy ◽  
...  
Keyword(s):  
Systematic Review ◽  
Deep Learning ◽  
Meta Analysis ◽  
High Accuracy ◽  
Risk Of Bias ◽  
Automated Detection ◽  
Reference Test ◽  
Landmark Detection ◽  
Future Studies ◽  
Using Data

Abstract Objectives Deep learning (DL) has been increasingly employed for automated landmark detection, e.g., for cephalometric purposes. We performed a systematic review and meta-analysis to assess the accuracy and underlying evidence for DL for cephalometric landmark detection on 2-D and 3-D radiographs. Methods Diagnostic accuracy studies published in 2015-2020 in Medline/Embase/IEEE/arXiv and employing DL for cephalometric landmark detection were identified and extracted by two independent reviewers. Random-effects meta-analysis, subgroup, and meta-regression were performed, and study quality was assessed using QUADAS-2. The review was registered (PROSPERO no. 227498). Data From 321 identified records, 19 studies (published 2017–2020), all employing convolutional neural networks, mainly on 2-D lateral radiographs (n=15), using data from publicly available datasets (n=12) and testing the detection of a mean of 30 (SD: 25; range.: 7–93) landmarks, were included. The reference test was established by two experts (n=11), 1 expert (n=4), 3 experts (n=3), and a set of annotators (n=1). Risk of bias was high, and applicability concerns were detected for most studies, mainly regarding the data selection and reference test conduct. Landmark prediction error centered around a 2-mm error threshold (mean; 95% confidence interval: (–0.581; 95 CI: –1.264 to 0.102 mm)). The proportion of landmarks detected within this 2-mm threshold was 0.799 (0.770 to 0.824). Conclusions DL shows relatively high accuracy for detecting landmarks on cephalometric imagery. The overall body of evidence is consistent but suffers from high risk of bias. Demonstrating robustness and generalizability of DL for landmark detection is needed. Clinical significance Existing DL models show consistent and largely high accuracy for automated detection of cephalometric landmarks. The majority of studies so far focused on 2-D imagery; data on 3-D imagery are sparse, but promising. Future studies should focus on demonstrating generalizability, robustness, and clinical usefulness of DL for this objective.

Planning future studies based on the precision of network meta-analysis results

2015 ◽  
Vol 35 (7) ◽  
pp. 978-1000 ◽  
Author(s):  
Adriani Nikolakopoulou ◽  
Dimitris Mavridis ◽  
Georgia Salanti
Keyword(s):  
Meta Analysis ◽  
Future Studies

Abstract 302: Sex Differences In Nonlinear Dynamics And Their Circadian Variation In Control Dogs And In A New Arrhythmogenic Canine Model Of Heart Failure

2014 ◽  
Vol 115 (suppl_1) ◽  
Author(s):  
Yujie Zhu ◽  
Steven M Pogwizd
Keyword(s):  
Nonlinear Dynamics ◽  
Heart Failure ◽  
Sex Differences ◽  
Sex Difference ◽  
Circadian Variation ◽  
Holter Monitoring ◽  
Canine Model ◽  
Nonlinear Parameters ◽  
Arrhythmogenic Substrate ◽  
Males And Females

Introduction: Females can be more arrhythmogenic than males, and this sex difference can persist with development of chronic heart failure (CHF). The aim of this study was to investigate sex differences in the arrhythmogenic substrate in control dogs and in a new arrhythmogenic canine model of CHF. Methods: CHF was induced in 30 dogs by aortic insufficiency and aortic constriction. Holter monitoring assessed VT and PVCs from 30 dogs, as well as traditional HRV measures and nonlinear dynamics (including correlation dimension (CD), detrended fluctuations analysis α1 (DFAα1), and Shannon entropy (SE)) at baseline, 240 days (240d) and 720 days (720d) after CHF induction. Results: At baseline, females had lower LF/HF (0.27±0.03 vs 0.33±0.02, p=0.04), CD (1.60±0.17 vs 2.21±0.15, p=0.01), DFAα1 (0.62±0.03 vs 0.72±0.03, p=0.03), and SE (2.99±0.02 vs 3.10±0.03, p=0.03 vs males). Females lacked circadian variation in LF/HF, DFAα1, and SE while males had circadian variation in all of these. Of 11 dogs with frequent runs of VT and PVCs, 95% and 91% of total VT runs and total PVCs, respectively, were in females. With CHF, all these linear and nonlinear parameters progressively declined in males and females. CHF females had less decline in LF/HF than males so that by 720 days there was no more sex difference (0.24±0.06, 0.17±0.03 in females vs 0.22±0.05, 0.18±0.01 in males at 240d, 720d). However, for nonlinear parameters of CD, DFAα1, and SE, CHF females had lower values than males (CD: 1.56±0.21, 0.99±0.32 vs 1.87±0.24, 1.50±0.34; DFAα1: 0.51±0.05, 0.43±0.04 vs 0.54±0.07, 0.48±0.04; and SE 2.93±0.08, 2.76±0.08 vs 3.01±0.11, 2.91±0.04 in females vs males at 240d, 720d). With CHF, circadian variation in CD, DFAα1, and SE were lost in both males and females. Conclusions: There are sex differences in the arrhythmogenic substrate in control dogs and in this new arrhythmogenic canine model of moderate CHF. At baseline, females have lower sympathetic stimulation, reduced cardiac chaos, and loss of circadian variation in nonlinear dynamics. With CHF, sex differences in nonlinear dynamics persist; this reflects a loss of complexity and fractal properties that could contribute to increased arrhythmias in female CHF dogs.

Sign in / Sign up

Export Citation Format

Share Document