A Computational Framework for Age‐at‐Death Estimation from the Skeleton: Surface and Outline Analysis of 3D Laser Scans of the Adult Pubic Symphysis

In forensic anthropology, age‐at‐death estimation typically requires the macroscopic assessment of the skeletal indicator and its association with a phase or score. High subjectivity and error are the recognized disadvantages of this approach, creating a need for alternative tools that enable the objective and mathematically robust assessment of true chronological age. We describe, here, three fully computational, quantitative shape analysis methods and a combinatory approach that make use of three‐dimensional laser scans of the pubic symphysis. We report a novel age‐related shape measure, focusing on the changes observed in the ventral margin curvature, and refine two former methods, whose measures capture the flatness of the symphyseal surface. We show how we can decrease age‐estimation error and improve prior results by combining these outline and surface measures in two multivariate regression models. The presented models produce objective age‐estimates that are comparable to current practices with root‐mean‐square‐errors between 13.7 and 16.5 years.     

The Utility of the Samworth and Gowland Age‐at‐Death “Look‐up” Tables in Forensic Anthropology*

Abstract: Accurate age‐at‐death estimates are crucial to forensic anthropologists when onstructing biological profiles aimed at narrowing a missing‐persons list and to allow for timely and efficient identification of an unknown victim. The present contribution evaluates the utility of three new age‐at‐death estimation techniques recently proposed by Samworth and Gowland (2007). Results indicate that, in the samples under study, the Samworth and Gowland estimates from the pubic symphysis and auricular surface perform similar to alternate phase methods. The combined method does not appear to further enhance either the precision or the accuracy of the single pubic symphysis age‐at‐death estimate. In conclusion, these new methods seem to be more robust to distribution deviations than originally proposed by Samworth and Gowland (2007). They are therefore suitable for immediate and reliable forensic usage in the United States and worthy of further research for their use in North American forensic contexts.     

Using PMCT of Individuals of Known Age to Test the Suchey–Brooks Method of Aging in Victoria,Australia

The estimation of an individual's age at death plays a critical role in the investigation of unidentified human remains. The Suchey–Brooks method, which involves the analysis of degenerative morphological changes in the pubic symphysis, is currently widely used to estimate age in adults. This study tested the applicability of the Suchey–Brooks method on a contemporary adult Australian (Victorian) subpopulation by observing three‐dimensional volume‐rendered postmortem computed tomographic (PMCT) reconstructions of the pubic symphysis of 204 individuals aged 15–100 years. Results showed the method was reliable for females (85% correct allocations) but not for males (67% correct allocations). It is therefore recommended that extreme caution be used when applying the Suchey–Brooks method for estimating age at death of an individual in this subpopulation from PMCT images. The results suggest further investigation into alternate age estimation methods is required.     

A Comparative Assessment of the Chen et al. and Suchey‐Brooks Pubic Aging Methods on a North American Sample, ,

Accurately estimating the age‐at‐death of adult human skeletons is fundamental in forensic anthropology. This study evaluates the accuracy of two pubic bone age estimation methods—Chen et al. and Suchey‐Brooks. Specimens were obtained from a known collection of modern pubic bones curated at the Maricopa County Forensic Science Center in Phoenix, Arizona. A sample of 296 left male pubic bones of European ancestry was statistically evaluated via bias, absolute mean error, and intra‐ and inter‐observer error. Results indicate that the two methods are similar; the Suchey‐Brooks method is the most accurate for aging young adults (error c. 7 years), while the Revised Chen et al. method is most accurate for aging middle‐age adults (error c. 6 years). Thus, the Chen et al. method is an important contribution to forensic anthropology for aging older adult skeletal remains. There are, however, some limitations such as subjectivity and the intricate scoring system of Chen et al. method.     

A Test of Hartnett's Revisions to the Pubic Symphysis and Fourth Rib Methods on a Modern Sample

Estimating age at death is one of the most important aspects of creating a biological profile. Most adult age estimation methods were developed on North American skeletal collections from the early to mid‐20th century, and their applicability to modern populations has been questioned. In 2010, Hartnett used a modern skeletal collection from the Maricopia County Forensic Science Centre to revise the Suchey‐Brooks pubic symphysis method and the ??can et al. fourth rib methods. The current study tests Hartnett's revised methods as well as the original Suchey‐Brooks and ??can et al. methods on a modern sample from the William Bass Skeletal Collection (N = 313, mean age = 58.5, range 19–92). Results show that the Suchey‐Brooks and ??can et al. methods assign individuals to the correct phase 70.8% and 57.5% of the time compared with Hartnett's revised methods at 58.1% and 29.7%, respectively, with correctness scores based on one standard deviation of the mean rather than the entire age range. Accuracy and bias scores are significantly improved for Hartnett's revised pubic symphysis method and marginally better for Hartnett's revised fourth rib method, suggesting that the revised mean ages at death of Hartnett's phases better reflect this modern population. Overall, both Hartnett's revised methods are reliable age estimation methods. For the pubic symphysis, there are significant improvements in accuracy and bias scores, especially for older individuals; however, for the fourth rib, the results are comparable to the original ??can et al. methods, with some improvement for older individuals.     

A Comparison of Different Age Estimation Methods of the Adult Pelvis

The adult human pelvis is useful to estimate age because it contains three age indicators—the pubic symphysis, auricular surface, and acetabulum. This study tested the accuracy, inaccuracy, and bias of age estimation from the Suchey‐Brooks pubic symphysis, Osborne auricular surface, Rissech and Calce acetabulum aging methods, and a summary age of these indicators. The study sample consisted of 212 White individuals with known age and sex from the William M. Bass Donated Skeletal Collection. The Rissech method performed the best, was the most accurate method with smallest inaccuracy and bias, followed by the Osborne, Suchey‐Brooks, summary age, and then Calce methods. Though the Pearson correlation showed only the Suchey‐Brooks method to correlate significantly with known age, it is likely the Suchey‐Brooks study sample coincidentally reflected the age distribution of this test sample. Results suggested that Bayesian prediction may improve age estimation and should be applied to other age indicators.     

Pubic Symphyseal Age Estimation from Three‐Dimensional Reconstructions of Pelvic CT Scans of Live Individuals

Skeletal age estimation using the pubic symphysis is a reliable and popular practice among forensic anthropologists. In instances in which accessing the skeleton is impossible, such as in the case of living individuals, three‐dimensional (3D) reconstructions of computed tomography (CT) scans can be created and analyzed for aspects of the biological profile. This study examined 3D reconstructions of pelvic CT scans of a sample of 44 live adults to estimate age using the Suchey–Brooks J Hum Evol 1990;5(3):227‐38 method. Images were created using OsiriX software (Pixmeo, Geneva, Switzerland). Estimated age ranges based on the 3D‐CT images captured the true age of the individual at the time of the CT scan 79.5% of the time with good intra‐observer reliability. The features best visualized on the 3D images included the ossific nodule and the pubic symphyseal rim. This study shows that clinical CT scanning parameters are adequate for creating 3D images to be analyzed for age using the pubic symphysis.     

A Bayesian Approach to Age‐at‐Death Estimation from Osteoarthritis of the Shoulder in Modern North Americans

Osteoarthritis (OA) is a marker of degeneration within the skeleton, frequently associated with age. This study quantifies the correlation between OA and age‐at‐death and investigates the utility of shoulder OA as a forensic age indicator using a modern North American sample of 206 individuals. Lipping, surface porosity, osteophyte formation, eburnation, and percentage of joint surface affected were recorded on an ordinal scale and summed to create composite scores that were assigned a specific phase. Spearman's correlation indicated a positive relationship between each composite score and age (right shoulder = 0.752; left shoulder = 0.734). Transition analysis revealed a tendency toward earlier degeneration of the right shoulder. Bayesian statistics generated phase‐related age estimates based on highest posterior density regions. Best age estimates were into the seventh decade at the 90th and 50th percentile. The proposed method supplements traditional techniques by providing age estimates beyond a homogenous 50+ age cohort.     

Testing Reliability of the Computational Age‐At‐Death Estimation Methods between Five Observers Using Three‐Dimensional Image Data of the Pubic Symphysis,

In an effort to standardize data collection and analysis in age estimation, a series of computational methods utilizing high‐dimensional image data of the age indicator have recently been proposed as an alternative to subjective visual, trait‐to‐phase matching techniques. To systematically quantify the reproducibility of such methods, we investigate the intrascan variability and within‐ and between‐observer reliability in initial scan data capturing and editing using 3D laser scans of the Suchey–Brooks pubic symphysis casts and five shape‐based computational methods. Our results show that (i) five observers with various training background and experience levels edited the scans consistently for all three trials and the derived shape measures and age estimates were in excellent agreement among observers, and (ii) the computational methods are robust to a measured degree of scan trimming error. This study supports the application of computational methods to 3D laser scanned images for reliable age‐at‐death estimation, with reduced subjectivity.     

Age estimation from the human os coxa: a test on a documented Italian collection*

Current standards for age at death estimation from the pelvis are based on Americans of European and African ancestry. Our limited understanding of population variability hampers our efforts to apply these techniques to the various skeletal populations around the world, especially in global forensic contexts. However, documented skeletal samples are rare, limiting our ability to test our techniques. This study tested the Suchey-Brooks pubic symphysis aging method and the auricular surface method originally developed by Lovejoy et al. on a large sample (n = 404) of known sex and age from the Sassari Collection, housed at the Museum of Anthropology at the University of Bologna, Italy. The results indicate that for both methods, bias and inaccuracy increased with age and actual age tended to be underestimated over the age of 40. The auricular surface method performed slightly better, exhibiting slightly lower levels of bias and inaccuracy, especially for males.     

Quantification of Pubic Symphysis Metamorphosis Based on the Analysis of Clinical MDCT Scans in a Contemporary Malaysian Population

Forensic age estimation methods are biased to sex and population; in general, accuracy is reduced when applied to foreign populations. This study assessed the accuracy of the Suchey–Brooks method in contemporary Malaysian individuals and aimed to formulate population‐specific standards. Multi‐detector computed tomography scans of 355 individuals (165 male; 190 female) of 15–83 years of age were reconstructed using 3D‐volumetric rendering in RadiAnt. Pubic symphyseal phase, bias, inaccuracy, and percentage correct age classifications are examined. Transition analysis was used to develop age estimation standards. High observer agreement (κ = 0.763–0.832) and a positive relationship between age and pubic symphyseal phase (r = 0.884–0.90) were demonstrated. Mean inaccuracies were 8.62 and 8.95 years for males and females, respectively; overall correct classification was 97.8%. Transition ages between phases in males were 18.79, 23.29, 28.85, 43.64, and 61.15 years; in females, the corresponding data were 19.77, 22.53, 32.62, 41.85, and 57.39 years.     

Age Estimation of Adult Living Donor by Pubic MSCT Three-dimensional ReconstructionCSCD

Objective: To establish a method for the age estimation of adult living donor based on pubic MSCT three-dimensional reconstruction and verify its accuracy and reliability. Methods: The volume rendering (VR)image data of pubic symphysis surface were collected from 300 volunteers aged over 17 years old. According to different age groups, the age estimation of these volunteers was performed by the method and formula of pubic symphysis surface. Results: In the 300 volunteers, the difference between biological age and actual age was <1 year in 117 cases, >1-2 years in 178 cases, >2 years in 5 cases. Conclusion: MSCT three-dimensional reconstruction technology of pubic symphysis surface can be used to estimate the age of adult living donor, which can provide a high accurate and reliable result. © 2018 by the Editorial Department of Journal of Forensic Medicine.     

Auricular Surface Aging: Comparing Two Methods that Assess Morphological Change in the Ilium with Bayesian Analyses

Modern standards in forensic anthropology require rigorous testing and evaluation of methods used for aging skeletal remains. Age estimation has been criticized for bias, inaccuracy, and population specificity; issues which are minimized by the application of Bayesian methodology. Using Bayesian statistics, we compare the Lovejoy et al. (Am J Phys Anthropol, 68, 1985, 15) (original) and Buckberry and Chamberlain (Am J Phys Anthropol, 119, 2002, 231) (revised) auricular surface aging methods. Transition analysis parameters derived from American males (n = 372), in combination with a Thai male (N = 37) informative prior, statistically model age in Portuguese males (n = 221). Cumulative binomial tests assess the accuracy of the generated age ranges. Overall, the application of transition analysis and Bayesian statistics significantly improved age estimation with both methods (also outperforming Suchey‐Brooks pubic symphysis aging). Moreover, the accuracy of the original method was low without statistical modeling, whereas the revised method can be applied accurately without further statistical analysis. Additionally, reference tables for aging Portuguese males are provided.     

重建耻骨联合三维结构用于活体年龄推断的技术方法

目的建立基于MRI成像的快速耻骨联合三维结构重建技术方法。方法利用3.0 T超导磁共振仪对成年男性志愿者骨盆进行T1小角度快速激发3D梯度回波序列扫描,进行二值化阈值分割、区域增长提取骨盆软组织图像;运算获得耻骨联合三维结构模型雏形,经逆向工程软件降噪处理建立耻骨联合三维结构模型,并与耻骨CT扫描三维结构重建模型进行比较。结果耻骨联合面沟嵴、下端、腹侧缘(斜面)、背侧缘(斜面)、耻骨结节等结构显示完整,无明显噪点,与CT扫描三维重建模型吻合较好。结论 MRI扫描成像可实现快速有效的耻骨联合三维结构重建,可为法医活体年龄推断提供安全无辐射作用的三维可视化影像学技术方法。     

A Four‐Stage Method of Age at Death Estimation for Use in the Subadult Rib Cortex*,†

Abstract: Age estimation in the subadult skeleton can be rather precise when the epiphyses and dentition are present, but incomplete or commingled remains still present a challenge. Histomorphometric age‐at‐death estimation methods developed for use on adults are based on the age‐associated accumulation of osteons. In the growing skeleton, there is a poor correlation between osteon numbers and age until the latter half of the second decade. As a result, there has been no histological aging method for use in subadults. The analysis of the rib cortex of 72 subadults ranging in age from 2 to 21 years has identified a series of developmental changes in the bone microstructure that can be used to estimate age. This qualitative method utilizes the systematic changes in rib cortical morphology to classify ribs into one of four age phases. This method can be applied to immature skeletons in forensic, archaeological, and paleontological contexts.     

Effects of Parturition on Pelvic Age Indicators

This research assessed whether parity has a differential effect on age indicators of the pelvis. The data were collected from the William M. Bass Donated Skeletal Collection. Age indicators of the pubic symphysis and auricular surface were assessed using the Todd, Suchey–Brooks, Lovejoy et al., and Buckberry and Chamberlain scoring systems. A transition analysis was conducted, and scoring systems of the pubic symphysis showed the parous female group transitioning between eight and 14 years earlier than the nulliparous female and male groups, and 1 and 7 years earlier using the auricular surface methods. A likelihood ratio test produced significantly different results between parous and nulliparous females using the pubic symphysis (p < 0.01) but not the auricular surface (p > 0.05). Although parous females were inaccurately assessed more often than nulliparous females, no correction of methods is necessary at this time as current standards take parity into account by utilizing a lumped female sample.     

Validation of the Acetabulum As a Skeletal Indicator of Age at Death in Modern European‐Americans,

Progressive changes in the acetabulum have been used in modern skeletal age estimation, but they have not been completely understood. If their age correlations are weakened by the influence of factors like physical activity and obesity, acetabular changes should not be used for age estimation. To investigate their utility for aging, the acetabular variables of Rissech et al. (2006) were analyzed in 409 modern European‐Americans (Bass Collection, Tennessee). Correlation tests assessed potential associations between acetabular data, osteoarthritis scores (collected per Jurmain, 1990), and documented demographic information (age, body mass index [BMI], metabolic intensity of physical activities). Acetabular changes had statistically significant, positive correlations with osteoarthritis (p < 0.001 in most joints/regions) and age (p < 0.001), indicating their degenerative nature and relevance for age estimation. Acetabular changes showed no associations with BMI or metabolic values, suggesting resistance to obesity and activity effects. These results suggest that acetabular degeneration is a valid skeletal age‐at‐death indicator.