Harold Matthews- PhD
- PostDoc Position at KU Leuven
Harold Matthews
- PhD
- PostDoc Position at KU Leuven
About
95
Publications
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869
Citations
Introduction
Harold Matthews currently works at the department of Human Genetics at KU, Leuven. He specialises in spatially-dense morphometric analysis, particularly applied to human faces. His current work focuses on exploring and modelling normal facial variation, as well as basic image processing,
Current institution
Publications
Publications (95)
Importance:
Children who receive a diagnosis of fetal alcohol spectrum disorder may have a characteristic facial appearance in addition to neurodevelopmental impairment. It is not well understood whether there is a gradient of facial characteristics of children who did not receive a diagnosis of fetal alcohol spectrum disorder but who were exposed...
Many disorders present with characteristic abnormalities of the craniofacial complex. Precise descriptions of how and when these abnormalities emerge and change during childhood and adolescence can inform our understanding of their underlying pathology and facilitate diagnosis from craniofacial shape. In this paper we develop a framework for analys...
3D facial images are becoming increasingly common. They provide more information about facial form than their 2D counterparts and will be useful in future forensic applications. These include age estimation and predicting changes in appearance of missing persons (synthetic growth). We present a framework for both age estimation and synthetic growth...
Recent advances in the field of geometric morphometrics allow for powerful statistical hypothesis testing for effects of biological and environmental variables on anatomical shape. This study used partial least-squares regression (PLSR) and the recently developed bootstrapped response-based imputation modelling (BRIM) algorithm to test for sexual d...
Congenital midline cervical cleft (CMCC) is a rare condition that consists of a cutaneous midline neck lesion with a sinus extending inferiorly towards the sternum. A fibrous band that extends superiorly to the mandible is a consistent feature of the condition. Restriction of growth of the mandible, possibly due to incomplete removal of the band, i...
Importance
In addition to confirmed prenatal alcohol exposure and severe neurodevelopmental deficits, three cardinal facial features are included in the diagnostic criteria for fetal alcohol spectrum disorder. It is not understood whether subtle facial characteristics occur in children without a diagnosis but who were exposed to a range of common p...
Condylar resorption is a feared complication of orthognathic surgery. This study investigated condylar resorption in a cohort of 200 patients This allowed for a powerful update on incidence and risk factors. 9.5% of patients developed resorption. These patients had on average, 17% volume loss with 3.9 mm ramal height loss and 3.1 mm posterior mandi...
Human craniofacial shape is highly variable yet highly heritable with numerous genetic variants interacting through multiple layers of development. Here, we hypothesize that Mendelian phenotypes represent the extremes of a phenotypic spectrum and, using achondroplasia as an example, we introduce a syndrome-informed phenotyping approach to identify...
Human facial shape, while strongly heritable, involves both genetic and structural complexity, necessitating precise phenotyping for accurate assessment. Common phenotyping strategies include simplifying 3D facial features into univariate traits such as anthropometric measurements (e.g., inter-landmark distances), unsupervised dimensionality reduct...
Human facial shape, while strongly heritable, involves both genetic and structural complexity, necessitating precise phenotyping for accurate assessment. Common phenotyping strategies include simplifying 3D facial features into univariate traits such as anthropometric measurements (e.g., inter-landmark distances), unsupervised dimensionality reduct...
Automatic dense 3D surface registration is a powerful technique for comprehensive 3D shape analysis that has found a successful application in human craniofacial morphology research, particularly within the mandibular and cranial vault regions. However, a notable gap exists when exploring the frontal aspect of the human skull, largely due to the in...
Automatic dense 3D surface registration is a powerful technique for comprehensive 3D shape analysis that has found a successful application in human craniofacial morphology research, particularly within the mandibular and cranial vault regions. However, a notable gap exists when exploring the frontal aspect of the human skull, largely due to the in...
Clinical diagnosis of syndromes benefits strongly from objective facial phenotyping. This study introduces a novel approach to enhance clinical diagnosis through the development and exploration of a low-dimensional metric space referred to as the clinical face phenotypic space (CFPS). As a facial matching tool for clinical genetics, such CFPS can e...
Transcriptional regulation exhibits extensive robustness, but human genetics indicates sensitivity to transcription factor (TF) dosage. Reconciling such observations requires quantitative studies of TF dosage effects at trait-relevant ranges, largely lacking so far. TFs play central roles in both normal-range and disease-associated variation in cra...
Objectives
(1) To investigate the effect of age and diet consistency on maximum lips, tongue and cheek pressure of orthodontically treated and untreated subjects with normal, Class I dental occlusion, (2) to find out whether there is a muscle imbalance between anterior tongue and lip pressure in the same subjects at different ages and (3) to compar...
The effects of sex on human facial morphology have been widely documented. Because sexual dimorphism is relevant to a variety of scientific and applied disciplines, it is imperative to have a complete and accurate account of how and where male and female faces differ. We apply a comprehensive facial phenotyping strategy to a large set of existing 3...
Facial ancestry can be described as variation that exists in facial features that are shared amongst members of a population due to environmental and genetic effects. Even within Europe, faces vary among subregions and may lead to confounding in genetic association studies if unaccounted for. Genetic studies use genetic principal components (PCs) t...
Clinical diagnosis of syndromes benefits strongly from objective facial phenotyping. This study investigates facial dysmorphism of genetic syndromes by building and investigating a low-dimensional metric space referred to as the clinical face phenotypic space (CFPS). As a facial matching tool for clinical genetics, such CFPS can enhance clinical di...
Background and objective(s)
(1) To derive descriptive statistics of three-dimensional (3D) facial shape, lip and cheek muscle pressure in subjects of European descent with normal dental occlusion. (2) To analyse the effect of age and sex on 3D-facial soft tissue morphology and muscle pressure in the same sample. (3) To assess the independent effect...
Genome-wide association studies (GWAS) identified thousands of genetic variants linked to phenotypic traits and disease risk. However, mechanistic understanding of how GWAS variants influence complex morphological traits and can, in certain cases, simultaneously confer normal-range phenotypic variation and disease predisposition, is still largely l...
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Introduction
To objectively quantify nasal characteristics of patients with asymmetric mandibular prognathism and to evaluate the association between nasal asymmetry and dentofacial abnormalities.
Methods
Ninety adult patients with asymmetric mandibular prognathism were included. Images were captured during pretreatment using 3-dimensional stereop...
Background
In clinical genetics, establishing an accurate nosology requires analysis of variations in both aetiology and the resulting phenotypes. At the phenotypic level, recognising typical facial gestalts has long supported clinical and molecular diagnosis; however, the objective analysis of facial phenotypic variation remains underdeveloped. In...
Transcriptional regulation displays extensive robustness, but human genetics indicate sensitivity to transcription factor (TF) dosage. Reconciling such observations requires quantitative studies of TF dosage effects at trait-relevant ranges, which are lacking to date. TFs play central roles in both normal-range and disease-associated variation in f...
Purpose:
To apply geometric morphometrics and multivariate statistics to evaluate changes of the face for female Chinese patients who underwent orthodontic treatment with different type of anchorage control.
Methods:
Forty-six adult female patients were enrolled including 33 four first premolars extraction cases (17 patients with mini-implants f...
Introduction
This study aimed to develop an automatic pipeline for analyzing mandibular shape asymmetry in 3-dimensions.
Methods
Forty patients with skeletal Class I pattern and 80 patients with skeletal Class III pattern were used. The mandible was automatically segmented from the cone-beam computed tomography images using a U-net deep learning n...
Deviation from a normal facial shape and symmetry can arise from numerous sources, including physical injury and congenital birth defects. Such abnormalities can have important aesthetic and functional consequences. Furthermore, in clinical genetics distinctive facial appearances are often associated with clinical or genetic diagnoses; the recognit...
Identification and delineation of craniofacial characteristics support the clinical and molecular diagnosis of genetic syndromes. Deep learning (DL) frameworks for syndrome identification from 2D facial images are trained on large clinical datasets using standard convolutional neural networks for classification. In contrast, despite the increased a...
Facial morphology is highly variable, both within and among human populations, and a sizable portion of this variation is attributable to genetics. Previous genome scans have revealed more than 100 genetic loci associated with different aspects of normal-range facial variation. Most of these loci have been detected in Europeans, with few studies fo...
Objectives:
Palatal shape contains a lot of information that is of clinical interest. Moreover, palatal shape analysis can be used to guide or evaluate orthodontic treatments. A statistical shape model (SSM) is a tool that, by means of dimensionality reduction, aims at compactly modeling the variance of complex shapes for efficient analysis. In th...
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Objective
Quantification and visualization of the location and magnitude of facial asymmetry is important for diagnosis and treatment planning. The objective of this study was to analyze the asymmetric features of the face for skeletal Class III patients using spatially-dense geometric morphometrics.
Methods
Three-dimensional facial images were ob...
Craniofacial dysmorphism is associated with thousands of genetic and environmental disorders. Delineation of salient facial characteristics can guide clinicians towards a correct clinical diagnosis and understanding the pathogenesis of the disorder. Abnormal facial shape might require craniofacial surgical intervention, with the restoration of norm...
Objectives
To develop and evaluate a geometric deep-learning network to automatically place seven palatal landmarks on digitized maxillary dental casts.
Settings and Sample population
The sample comprised individuals with permanent dentition of various ethnicities. The network was trained from manual landmark annotations on 732 dental casts and ev...
Automatic craniomaxillofacial (CMF) three dimensional (3D) dense phenotyping promises quantification of the complete CMF shape compared to the limiting use of sparse landmarks in classical phenotyping. This study assesses the accuracy and reliability of this new approach on the human mandible. Classic and automatic phenotyping techniques were appli...
Background and Objective; Genetic risk factors for childhood cancer may also influence facial morphology. 3D photography can be used in the recognition of differences in face shape among individuals. In previous research, 3D facial photography was used to identify increased facial asymmetry and greater deviation from normal facial morphology in a g...
The contribution of low-frequency variants to the genetic architecture of normal-range facial traits is unknown. We studied the influence of low-frequency coding variants (MAF < 1%) in 8091 genes on multi-dimensional facial shape phenotypes in a European cohort of 2329 healthy individuals. Using three-dimensional images, we partitioned the full fac...
Background and Objectives
Multilevel statistical models represent the existence of hierarchies or clustering within populations of subjects (or shapes in this work). This is a distinct advantage over single-level methods that do not. Multilevel partial-least squares regression (mPLSR) is used here to study facial shape changes with age during adol...
Hypothesis and Background
Rotator Cuff Tear Arthropathy (RCTA) is a pathology characterized by a massive rotator cuff tear combined with acromiohumeral and/or glenohumeral arthritis. Severity of RCTA can be staged according to Hamada. It is unknown why some patients develop RCTA. Furthermore, RCTA patients can develop distinctly different articular...
The contribution of low-frequency variants to the genomic architecture of normal-range facial traits is unknown. Therefore, we studied the influence of 31347 low-frequency coding variants (MAF < 1%) in 8091 genes on multi-dimensional facial shape phenotypes in a European cohort of 2329 healthy individuals. Using three-dimensional facial images, we...
Estimates of individual-level genomic ancestry are routinely used in human genetics, and related fields. The analysis of population structure and genomic ancestry can yield insights in terms of modern and ancient populations, allowing us to address questions regarding admixture, and the numbers and identities of the parental source populations. Unr...
Purpose:
The purpose of this study was to characterize the facial morphology of Chinese children with hypohidrotic ectodermal dysplasia (HED) and quantify facial changes after prosthetic treatment.
Methods:
3-D facial images of 12 HED children were taken and their facial morphology was compared against 28 healthy controls. Facial changes due to de...
Treatment of large acetabular defects and discontinuities remains challenging and relies on the accurate restoration of the native anatomy of the patient. This study introduces and validates a statistical shape model for the reconstruction of acetabular discontinuities with severe bone loss through a two-sided Markov Chain Monte Carlo reconstructio...
Three-dimensional (3D) photography is becoming widely used in plastic surgery. It provides an accurate and reproducible record of the facial surface anatomy and could be a versatile tool for treatment planning and assessment. However, the existing software tools available for the assessment of 3D facial imaging often give highly misleading results....
Abstract Background A functional appliance is commonly used to optimize the development of the facial skeleton in the treatment of Class II malocclusion. Recent three-dimensional(3D) image-based analysis offers numerous advantages in quantitative measurement and visualization in orthodontics. The aim of this study was to localize in 3D the skeletal...
mPCA Level 1 (ethnicity / sex) level: mode 1 from Finnish (mean - 3SD) to Welsh (mean + 3SD)
mPCA Level 3 (age) level: mode 1 from age 12 (mean - 3SD) to age 17 (mean + 3SD)
mPCA Level 1 (ethnicity / sex) level: mode 2 from Male (mean - 3SD) to Female (mean + 3SD)
mPCA Level 2 (all other "subject" variations) level: mode 1
Background and objectives:
The study of age-related facial shape changes across different populations and sexes requires new multivariate tools to disentangle different sources of variations present in 3D facial images. Here we wish to use a multivariate technique called multilevel principal components analysis (mPCA) to study three-dimensional fa...
Dense surface registration, commonly used in computer science, could aid the biological sciences in accurate and comprehensive quantification of biological phenotypes. However, few toolboxes exist that are openly available, non-expert friendly, and validated in a way relevant to biologists. Here, we report a customizable toolbox for reproducible hi...
Objectives:
The aim of the present study was to use Fourier analysis to quantify and study age-related changes in midsagittal facial profile.
Materials and methods:
Midsagittal facial profiles were extracted as lists of x and y coordinates from 125 pairs of 3D facial scans captured at an average of 10.5 years apart for adult Japanese males aged...
In the post-genomics era, an emphasis has been placed on disentangling 'genotype-phenotype' connections so that the biological basis of complex phenotypes can be understood. However, our ability to efficiently and comprehensively characterize phenotypes lags behind our ability to characterize genomes. Here, we report a toolbox for fast and reproduc...
Objectives::
To propose a reliable and practical method for automatically segmenting the mandible from CBCT images.
Methods::
The marker-based watershed transform is a region-growing approach that dilates or 'floods' predefined markers onto a height map whose ridges denote object boundaries. We applied this method to segment the mandible from th...
Objectives: To propose a reliable and practical method for automatically segmenting the mandible from low-dose CBCT images. Methods: The marker-based watershed transform is a region-growing approach that dilates or 'floods' predefined markers onto a height map whose ridges denote object boundaries. We applied this method to segment the mandible fro...
Fetal alcohol spectrum disorder (FASD) refers to the spectrum of teratogenic effects of prenatal alcohol exposure (PAE). Fetal alcohol syndrome (FAS) represents the extreme end of the spectrum and comprises somatic and neural growth deficiency, neurobehavioral impairment and a distinctive facial appearance (Hoyme et al., 2016). However, PAE affecte...
Accurate descriptions of normal craniofacial shape are essential for accurate assessment of pathologies of the craniofacial complex. Traditionally, these descriptions, have been limited to growth curves of single measurements (e.g. head circumference) to which a patient can be compared. In this thesis we exploit advances in 3D image capture and ima...
Many disorders present with characteristic abnormalities of the craniofacial complex. Precise descriptions of how and when these abnormalities emerge and change during childhood and adolescence can inform our understanding of their underlying pathology and facilitate diagnosis from craniofacial shape. In this paper we develop a framework for analys...
3D facial images are becoming increasingly common. They provide more information about facial form than their 2D counterparts and will be useful in future forensic applications. These include age estimation and predicting changes in appearance of missing persons (synthetic growth). We present a framework for both age estimation and synthetic growth...
Background: Children with Fetal Alcohol Spectrum Disorder (FASD) can have a characteristic facial appearance in addition to neurodevelopmental impairment. We do not know if there is a gradient of effects on the face of children with prenatal alcohol exposure (PAE). Method: This is an analysis of 3D craniofacial images of 415 one year-old Caucasian...
We measured the strength of the hollow-face illusion--the 'flipping distance' at which perception changes between convex and concave--as a function of a lens-induced 3 dioptre refractive error and monocular/binocular viewing. Refractive error and closing one eye both strengthened the illusion to approximately the same extent. The illusion was weake...
![Figure 1. [In colour online, see http://dx.doi.org/10.1068/p7187] These...](profile/Harold-Hill/publication/225279252/figure/fig1/AS:339863212707846@1458041112408/In-colour-online-see-http-dxdoiorg-101068-p7187-These-stereoscopic-photographs_Q320.jpg)
Evidence suggests that experiencing the hollow-face illusion involves perceptual reversal of the binocular disparities associated with the face even though the rest of the scene appears unchanged. This suggests stereoscopic processing of object shape may be independent of scene-based processing of the layout of objects in depth. We investigated the...
![Figure 1. [In colour online, see http://dx.doi.org/10.1068/p6915] When...](profile/Harold-Hill/publication/51844907/figure/fig2/AS:667678737985546@1536198424984/In-colour-online-see-http-dxdoiorg-101068-p6915-When-free-uncross-1-and-2-or_Q320.jpg)
The hollow-face illusion involves a misperception of depth order: our perception follows our top-down knowledge that faces are convex, even though bottom-up depth information reflects the actual concave surface structure. While pictorial cues can be ambiguous, stereopsis should unambiguously indicate the actual depth order. We used computer-generat...
The Dual Diagnosis Capability of Addiction Treatment (DDCAT) index is used to assess the capacity of substance abuse services to work with individuals with co-occurring mental health problems. The current study aimed to: (i) examine the dual diagnosis capability of residential substance abuse programs in Australia; (ii) identify managers' perceptio...
Questions
Questions (3)
I am writing a review article on facial analysis in biomedical data science. As part of this there is a section on automatic and manual facial landmarking.
There is a large literature on this topic in computer science, but it is usually more focussed on computer vision than medical applications.
I am wondering if there exists established and respected software for automatic landmarking of facial images in a biomedical context? Any help is much appreciated.
Harry
I am looking for a way to incorporate observation weights into a partial least-squares regression.
More specifically I want to extract the first pair of singular vectors u and v from the matrix XTY where X is an n observations x k predictors matrix and Y is an n observations x p response variables matrix.
When the observations are unweighted these singular vectors maximize the covariance between projections onto u and projections onto v. I would like this to emphasize maximizing the covariance between some observations more than others.
Any pointers are greatly appreciated.
Harry
We have a set of facial profiles - from the glabella between the eyebrows to the gnathion on the chin.
To me, it seems the most sensible way to decompose this shape into a Fourier series, would be to consider it as a single wave and use a standard Fourier decomposition.
I have noted, however, that most people facing the same problem will use an elliptical Fourier analysis, for the analysis of closed contours. In order to do this they will artificially make the surface closed e.g. by reflecting the profile and decomposing the two joined mirror images such as in Rose et al (2003) Lateral facial soft-tissue prediction model: Analysis using Fourier shape descriptors and traditional cephalometric methods. Am J. Phys. Anthropol. This is not the only paper to do this or something similar.
My question is: when the profile is simply an open line, why go to such lengths to use an elliptical Fourier decomposition, when the "regular" Fourier decomposition would serve the purpose? Or am I wrong that one could the "regular" Fourier decomposition in such a context?
