OBJECTIVE: Age-at-death estimation is usually done manually by experts. As such, manual estimation is subjective and greatly depends on the past experience and proficiency of the expert. This becomes even more critical if experts need to evaluate individuals with unknown population affinity or with affinity that they are not familiar with. The purpose of this study is to design a novel age-at-death estimation method allowing for automatic evaluation on computers, thus eliminating the human factor. METHODS: We used a traditional machine-learning approach with explicit feature extraction. First, we identified and described the features that are relevant for age-at-death estimation. Then, we created a multi-linear regression model combining these features. Finally, we analysed the model performance in terms of Mean Absolute Error (MAE), Mean Bias Error (MBE), Slope of Residuals (SoR) and Root Mean Squared Error (RMSE). RESULTS: The main result of this study is a population-independent method of estimating an individual's age-at-death using the acetabulum of the pelvis. Apart from data acquisition, the whole procedure of pre-processing, feature extraction and age estimation is fully automated and implemented as a computer program. This program is a part of a freely available web-based software tool called CoxAGE3D, which is available at https://coxage3d.fit.cvut.cz/. Based on our dataset, the MAE of the presented method is about 10.7 years. In addition, five population-specific models for Thai, Lithuanian, Portuguese, Greek and Swiss populations are also given. The MAEs for these populations are 9.6, 9.8, 10.8, 10.5 and 9.2 years, respectively. Our age-at-death estimation method is suitable for individuals with unknown population affinity and provides acceptable accuracy. The age estimation error cannot be completely eliminated, because it is a consequence of the variability of the ageing process of different individuals not only across different populations but also within a certain population.
- MeSH
- Acetabulum * diagnostic imaging MeSH
- Adult MeSH
- Middle Aged MeSH
- Humans MeSH
- Linear Models MeSH
- Young Adult MeSH
- Aged, 80 and over MeSH
- Aged MeSH
- Software * MeSH
- Forensic Anthropology * methods MeSH
- Machine Learning * MeSH
- Age Determination by Skeleton * methods MeSH
- Imaging, Three-Dimensional * MeSH
- Check Tag
- Adult MeSH
- Middle Aged MeSH
- Humans MeSH
- Young Adult MeSH
- Male MeSH
- Aged, 80 and over MeSH
- Aged MeSH
- Female MeSH
- Publication type
- Journal Article MeSH
Thanks to technical progress and the availability of virtual data, sex estimation methods as part of a biological profile are undergoing an inevitable evolution. Further reductions in subjectivity, but potentially also in measurement errors, can be brought by approaches that automate the extraction of variables. Such automatization also significantly accelerates and facilitates the specialist's work. The aim of this study is (1) to apply a previously proposed algorithm (Kuchař et al. 2021) to automatically extract 10 variables used for the DSP2 sex estimation method, and (2) to test the robustness of the new automatic approach in a current heterogeneous population. For the first aim, we used a sample of 240 3D scans of pelvic bones from the same individuals, which were measured manually for the DSP database. For the second aim a sample of 108 pelvic bones from the New Mexico Decedent Image Database was used. The results showed high agreement between automatic and manual measurements with rTEM below 5% for all dimensions except two. The accuracy of final sex estimates based on all 10 variables was excellent (error rate 0.3%). However, we observed a higher number of undetermined individuals in the Portuguese sample (25% of males) and the New Mexican sample (36.5% of females). In conclusion, the procedure for automatic dimension extraction was successfully applied both to a different type of data and to a heterogeneous population.
- MeSH
- Algorithms * MeSH
- Adult MeSH
- Middle Aged MeSH
- Humans MeSH
- Young Adult MeSH
- Pelvic Bones * diagnostic imaging MeSH
- Aged, 80 and over MeSH
- Aged MeSH
- Forensic Anthropology * methods MeSH
- Sex Determination by Skeleton * methods MeSH
- Imaging, Three-Dimensional * MeSH
- Check Tag
- Adult MeSH
- Middle Aged MeSH
- Humans MeSH
- Young Adult MeSH
- Male MeSH
- Aged, 80 and over MeSH
- Aged MeSH
- Female MeSH
- Publication type
- Journal Article MeSH
- Geographicals
- Portugal MeSH
The most significant sexual differences in the human skull are located in the upper third of the face (the frontal bone), which is a useful research object, mainly in combination with virtual anthropology methods. However, the influence of biological relatedness on sexual dimorphism and frontal bone variability remains unknown. This study was directed at sexual difference description and sex classification using the form and shape of the external surface of the frontal bones from a genealogically documented Central European osteological sample (nineteenth to twentieth centuries). The study sample consisted of 47 cranial CT images of the adult members of several branches of one family group over 4 generations. Three-dimensional virtual models of the frontal bones were analyzed using geometric morphometrics and multidimensional statistics. Almost the entire external frontal surface was significantly different between males and females, especially in form. Significant differences were also found between this related sample and an unrelated one. Sex estimation of the biologically related individuals was performed using the classification models developed on a sample of unrelated individuals from the recent Czech population (Čechová et al. in Int J Legal Med 133: 1285 1294, 2019), with a result of 74.46% and 63.83% in form and shape, respectively. Failure of this classifier was caused by the existence of typical traits found in the biologically related sample different from the usual manifestation of sexual dimorphism. This can be explained as due to the increased degree of similarity and the reduction of variability in biologically related individuals. The results show the importance of testing previously published methods on genealogical data.
- MeSH
- Frontal Bone * diagnostic imaging anatomy & histology MeSH
- Adult MeSH
- Humans MeSH
- Tomography, X-Ray Computed MeSH
- Sex Characteristics MeSH
- Forensic Anthropology * methods MeSH
- Sex Determination by Skeleton * methods MeSH
- Imaging, Three-Dimensional * MeSH
- Check Tag
- Adult MeSH
- Humans MeSH
- Male MeSH
- Female MeSH
- Publication type
- Journal Article MeSH
The skull, along with the pelvic bone, serves an important source of clues as to the sex of human skeletal remains. The frontal bone is one of the most significant sexually dimorphic structures employed in anthropological research, especially when studied by methods of virtual anthropology. For this reason, many new methods have been developed, but their utility for other populations remains to be verified. In the present study, we tested one such approach-the landmark-free method of Bulut et al. (2016) for quantifying sexually dimorphic differences in the shape of the frontal bone, developed using a sample of the Turkish population. Our study builds upon this methodology and tests its utility for the Czech population. We evaluated the shape of the male and female frontal bone using 3D morphometrics, comparing virtual models of frontal bones and corresponding software-generated spheres. To do so, we calculated the relative size of the frontal bone area deviating from the fitted sphere by less than 1 mm and used these data to estimate the sex of individuals. Using our sample of the Czech population, the method estimated the sex correctly in 72.8% of individuals. This success rate is about 5% lower than that achieved with the Turkish sample. This method is therefore not very suitable for estimating the sex of Czech individuals, especially considering the significantly greater success rates of other approaches.
- MeSH
- Frontal Bone anatomy & histology diagnostic imaging MeSH
- Adult MeSH
- Middle Aged MeSH
- Humans MeSH
- Young Adult MeSH
- Tomography, X-Ray Computed MeSH
- Computer Simulation * MeSH
- Image Processing, Computer-Assisted MeSH
- Aged, 80 and over MeSH
- Aged MeSH
- Forensic Anthropology MeSH
- Support Vector Machine MeSH
- Sex Determination by Skeleton methods MeSH
- Imaging, Three-Dimensional * MeSH
- Check Tag
- Adult MeSH
- Middle Aged MeSH
- Humans MeSH
- Young Adult MeSH
- Male MeSH
- Aged, 80 and over MeSH
- Aged MeSH
- Publication type
- Journal Article MeSH
- Geographicals
- Czech Republic MeSH
OBJECTIVES: This study aims at proposing a visual method for sexing the human os coxae based on a statistical approach, using a scoring system of traits described by Bruzek (2002). This method is evaluated on a meta-population sample, where the data were acquired by direct observation of dry bones as well as computed tomography (CT) scans. A comparison with the original Bruzek's (2002) method is performed. MATERIALS AND METHODS: Five hundred and ninety two ossa coxae of modern humans are included in the reference dataset. Two other samples, composed respectively of 518 ossa coxae and 99 CT-scan images, are both used for validation purposes. The individuals come from five European or North American population samples. Eleven trichotomic traits (expressing female, male, or intermediate forms) were observed on each os coxae. The new approach employs statistical processing based on logistic regressions. An R package freely available online, PELVIS, implements both methods. RESULTS: Both methods provide highly reliable sex estimates. The new statistical method has a slightly better accuracy rate (99.2%) than the former method (98.2%) but has also a higher rate of indeterminate individuals (12.9% vs. 3% for complete bones). CONCLUSION: The efficiency of both methods is compared. Low error rates were preferred over high ability of reaching the classification threshold. The impact of lateralization and the asymmetry of observed traits are discussed. Finally, it is shown that this visual method of sex estimation is reliable and easy to use through the graphical user interface of the R package.
- MeSH
- Adult MeSH
- Middle Aged MeSH
- Humans MeSH
- Logistic Models * MeSH
- Young Adult MeSH
- Pelvic Bones anatomy & histology MeSH
- Tomography, X-Ray Computed MeSH
- Aged, 80 and over MeSH
- Aged MeSH
- Forensic Anthropology methods MeSH
- Sex Determination by Skeleton methods MeSH
- Check Tag
- Adult MeSH
- Middle Aged MeSH
- Humans MeSH
- Young Adult MeSH
- Male MeSH
- Aged, 80 and over MeSH
- Aged MeSH
- Female MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
Sex assessment of skeletal remains in the context of forensic investigation is one of the most important components when constructing biological profile of the deceased individual since it helps to significantly narrow down the number of potential victims. Therefore, the number of methods suitable to estimate sex should be as wide as possible, especially for cases of highly fragmented remains. This paper offers a classification method for sexing human remains based on an area around foramen magnum and tests other similar discriminatory functions published elsewhere on an independent sample from the circummediterranean region. We provide discriminant and logistic regression functions for several sets of variable combinations derived from head CT images. None of the functions performs reliably enough to be used in the forensic context. The same holds true for other discriminatory functions published in the literature. For most of the functions, the failure rate (its inability to successfully assign sex of an unknown individual) reaches 100%. Thus, despite the fact that foramen magnum is sexually dimorphic in most populations, its use in sexing cranial remains in the forensic context should be limited only to cases in which we know population affinity of unknown skeletal remains and can provide referential data from the same population to estimate sex.
- MeSH
- Discriminant Analysis MeSH
- Foramen Magnum anatomy & histology diagnostic imaging MeSH
- Middle Aged MeSH
- Humans MeSH
- Logistic Models MeSH
- Tomography, X-Ray Computed MeSH
- Forensic Anthropology MeSH
- Sex Determination by Skeleton methods MeSH
- Check Tag
- Middle Aged MeSH
- Humans MeSH
- Male MeSH
- Female MeSH
- Publication type
- Journal Article MeSH
BACKGROUND: The aim of this study is to develop a population-specific reference for permanent tooth emergence among 4-15 years old Czech Republic children. The reference derived from this sample population are essential for pediatric dental diagnostics, orthodontic treatment planning, as well as anthropological and forensic applications. METHODS: In this cross-sectional epidemiological survey, dental examinations of 1,370 Czech children (696 girls (50,8%) and 674 boys (49,2%), whose parents or legal guardians all signed informed consent forms) from 11 elementary schools and kindergartens were performed in the classroom. During the examination, previously emerged permanent teeth (other than third molars), the child's age and gender were recorded. A tooth is defined as having erupted when at least any part of the crown penetrates the gingiva, and is clinically seen in the oral cavity. A logistic regression model was used to calculate the median emergence age per tooth for both genders and the total sample. The data was statistically processed (using IBM SPSS Statistics 23) and carried out at a deviation level of 0.05. The statistical significance of the differences in the emergence of permanent teeth (contralateral, intermaxillary, inter-gender differences) was evaluated by the McNemar test. RESULTS: No statistically significant differences were observed in the emergence times between right and left sides. In addition, mandibular teeth emerged earlier than the corresponding maxillary ones (with the exception of the first and second premolars). Permanent teeth were found to emerge sooner in girls. Furthermore, the greatest inter-gender difference was observed in maxillary canines. CONCLUSIONS: The new data reported can now be used as standards when assessing permanent tooth emergence of Czech children.
- MeSH
- Child MeSH
- Humans MeSH
- Adolescent MeSH
- Child, Preschool MeSH
- Tooth Eruption * MeSH
- Cross-Sectional Studies MeSH
- Reference Values MeSH
- Age Factors MeSH
- Check Tag
- Child MeSH
- Humans MeSH
- Adolescent MeSH
- Male MeSH
- Child, Preschool MeSH
- Female MeSH
- Publication type
- Journal Article MeSH
- Geographicals
- Czech Republic MeSH
Estimating an individual body mass (BM) from the skeleton is a challenge for forensic anthropology. However, identifying someone's BMI (Body Mass Index) category, i.e. underweight, normal, overweight or obese, could contribute to identification. Individual BM is also known to influence the age-at-death estimation from the skeleton. Several methods are regularly used by both archaeologists and forensic practitioners to estimate individual BM. The most commonly used methods are based on femoral head breadth, or stature and bi-iliac breadth. However, those methods have been created from mean population BMs and are therefore meant to estimate the average BM of a population. Being that they are based on individual BM data and estimated femoral cortical areas, the newest published methods are supposed to be more accurate. We evaluated the accuracy and reliability of the most commonly used and most recent BM estimation methods (n=11) on a sample of 64 individuals. Both sexes and all BMI categories are represented, as well as a wide range of BM. Ages in this sample range from 20 to 87 years of age. Absolute and real differences between actual BM and estimated BM were assessed; they determined the accuracy for individual BM estimation and for average BM estimation of a population, respectively. The proportion of the sample whose estimated BM falls within ±10% and ±20% of their actual BM determines the reliability of the methods in our sample for, respectively, individual BM estimation and average BM of a population. The tested methods result in an absolute difference of 11kg-26kg±10kg with regards to prediction of individuals actual BM. The real differences are very variable from method to method, ranging from -14kg to 25kg. None of the tested methods is able to estimate BM of half of the sample within ±10% of their actual BM but most of them can estimate BM of more than half of the sample within ±20% of their actual BM. The errors increase with increasing BM, demonstrating a bias in all the methods. No bone variable tested correlated with BM. BMI categories were correctly predicted for less than 50% of the sample in most cases. In conclusion, our study demonstrates that the 11 methods tested are not suited for estimating individual BM or for predicting BMI categories. However, they are accurate and reliable enough for estimating the average BM of a population.
- MeSH
- Adult MeSH
- Femur anatomy & histology diagnostic imaging MeSH
- Body Mass Index * MeSH
- Middle Aged MeSH
- Humans MeSH
- Young Adult MeSH
- Ilium anatomy & histology diagnostic imaging MeSH
- Tomography, X-Ray Computed MeSH
- Reproducibility of Results MeSH
- Aged, 80 and over MeSH
- Aged MeSH
- Forensic Anthropology methods MeSH
- Body Height MeSH
- Check Tag
- Adult MeSH
- Middle Aged MeSH
- Humans MeSH
- Young Adult MeSH
- Male MeSH
- Aged, 80 and over MeSH
- Aged MeSH
- Female MeSH
- Publication type
- Journal Article MeSH
In this paper we report, for the first time, on the distribution of 15 autosomal short tandem repeats (STRs) in Sarrabus, a region in south east Sardinia (Italy), for which there are no data in the literature. Samples were obtained from 77 unrelated normal subjects born and living in the three main villages of Sarrabus. In spite of being a homogeneous population, a high degree of polymorphism was observed: heterozygosity values range from 0.618 to 0.848 and Polymophism Information Content (PIC) values range from 0.579 to 0.853. When compared to other Sardinian populations, our data showed that Sarrabus is genetically well differentiated. This finding is consistent with the notion that Sardinia, although regarded as a homogeneous population, shows genetic heterogeneity when different microareas are analyzed. The implication in forensic medicine of our results, which describe a missing population, are discussed.
We studied sexual dimorphism of the human clavicle in order to describe size variation and create population-specific discriminant tools for morphometric sex assessment. The studied sample consisted of 200 skeletons of adult individuals obtained from the University of Athens Human Skeletal Reference Collection, Athens, Greece. The specimens were well-documented and represented a modern population from cemeteries in the Athens area. Six dimensions typically used for clavicle measurements were recorded. For sexing clavicles, we used both traditional univariate (limiting, demarking and sectioning points) and multivariate discriminant function analysis. The accuracy of the best five classification equations/functions ranged from 91.62% to 92.55% of correctly assigned specimens. By testing new and previously published sexing functions (Greeks, Polynesians, Guatemalans) on four available population samples (English, Indians from Amritsar, Indians from Varanasi, and data from the present study) we found that, for some combinations of tested and reference samples, the accuracy of the sex assessment may decrease even below the probability given by random sex assignment. Therefore, measurements of the clavicle should not be used for sex assessment of individual cases (both forensic and archeological) whose population origin is unknown. However, significant metric differences were also recorded among three different Greek samples (i.e. within a population). As a consequence, application of a sexing method generated from one Greek sample and applied to another Greek sample led to negligible reduction in the success of sex assessment, despite general similarities in ethnic origin (Greeks), generation structure and presumed social background of the samples. Therefore, we believe that future studies should focus on understanding the nature of the differences among within-population reference samples.
- MeSH
- Discriminant Analysis MeSH
- Adult MeSH
- Ethnicity MeSH
- Clavicle anatomy & histology MeSH
- Middle Aged MeSH
- Humans MeSH
- Young Adult MeSH
- Racial Groups MeSH
- Aged, 80 and over MeSH
- Aged MeSH
- Forensic Anthropology MeSH
- Sex Determination by Skeleton methods MeSH
- Check Tag
- Adult MeSH
- Middle Aged MeSH
- Humans MeSH
- Young Adult MeSH
- Male MeSH
- Aged, 80 and over MeSH
- Aged MeSH
- Female MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
- Comparative Study MeSH