Assessments of bilateral asymmetry with application in human skull analysis.

As a common feature, bilateral symmetry of biological forms is ubiquitous, but in fact rarely exact. In a setting of analytic geometry, bilateral symmetry is defined with respect to a point, line or plane, and the well-known notions of fluctuating asymmetry, directional asymmetry and antisymmetry are recast. A meticulous scheme for asymmetry assessments is proposed and explicit solutions to them are derived. An investigation into observational errors of points representing the geometric structure of an object offers a baseline reference for asymmetry assessment of the object. The proposed assessments are applicable to individual, part or all point pairs at both individual and collective levels. The exact relationship between the developed treatments and the widely used Procrustes method in asymmetry assessment is examined. An application of the proposed assessments to a large collection of human skull data in the form of 3D landmark coordinates finds: (a) asymmetry of most skulls is not fluctuating, but directional if measured about a plane fitted to shared landmarks or side landmarks for balancing; (b) asymmetry becomes completely fluctuating if one side of a skull could be slightly rotated and translated with respect to the other side; (c) female skulls are more asymmetric than male skulls. The methodology developed in this study is rigorous and transparent, and lays an analytical base for investigation of structural symmetries and asymmetries in a wide range of biological and medical applications.

Predicting Resting Oral Commissure Tone Outcomes Following Masseter Nerve Transfer in Facial Reanimation.

Objective: To quantify the degree of oral commissure resting tone improvement in patients undergoing masseter to facial nerve transfer. Methods: A retrospective cohort study was completed in a tertiary academic medical practice. Consecutive cases of masseter nerve transfer patients within a patient database were evaluated from 6/2012 to 9/2017. Inclusion criteria were patients >18 years of age, with complete unilateral paralysis, receiving a masseter to facial nerve transfer, with at least 12 months of recovery, and possessing complete pre- and postoperative data. Patients were excluded if a simultaneous adjunctive procedure was performed so that tone could not be attributed to masseter transfer alone. The main outcome measure was the facial asymmetry index (FAI): the measured difference in distance between the medial canthus and oral commissure of the healthy and paralyzed sides. Results: Twenty-nine patients met inclusion and exclusion criteria and were further analyzed for this study. The oral commissure symmetry improved from 4.7 ± 2.8 mm preoperatively to 2.2 ± 2.3 mm postoperatively. In multivariate analysis, the preoperative FAI was the only significant predictive factor for improvement in commissure symmetry at rest (r = 0.589). This suggests that for each 1.0 mm of worse preoperatively oral commissure asymmetry, the improvement postoperatively was 0.6 mm. Age, gender, body mass index, side of paralysis, duration of paralysis, and recipient branch of facial nerve were not significant predictors in a multivariate analysis. Conclusion: Masseter to facial nerve transfer yields an estimated 60% correction in the oral commissure asymmetry. This estimation may be helpful in determining if adjunctive procedures should be utilized.

Prior knowledge promotes hippocampal separation but cortical assimilation in the left inferior frontal gyrus.

An adaptive memory system rarely learns information tabula rasa, but rather builds on prior knowledge to facilitate learning. How prior knowledge influences the neural representation of novel associations remains unknown. Here, participants associated pairs of faces in two conditions: a famous, highly familiar face with a novel face or two novel faces while undergoing fMRI. We examine multivoxel activity patterns corresponding to individual faces before and after learning. The activity patterns representing members of famous-novel pairs becomes separated in the hippocampus, that is, more distinct from one another through learning, in striking contrast to paired novel faces that become similar. In the left inferior frontal gyrus, however, prior knowledge leads to integration, and in a specific direction: the representation of the novel face becomes similar to that of the famous face after learning, suggesting assimilation of new into old memories. We propose that hippocampal separation might resolve interference between existing and newly learned information, allowing cortical assimilation. Thus, associative learning with versus without prior knowledge relies on radically different computations.

Complications of botulinum toxin and fillers: A narrative review.

BACKGROUND: Cosmetic surgery and esthetic procedures have become a billion dollar industry owing to the ever-growing demand of the population to stay young. The injectable treatments including fillers and botulinum toxin have become highly popular because of their quick, predictable and lasting results in the management of facial wrinkles and rejuvenation. Although these treatment modalities are relatively safe, they are associated with certain side effects. AIMS: In this review, we will focus on the complications of fillers and botulinum toxin. PATIENTS/METHODS: The literature research considered published journal articles (clinical trials or scientific reviews). Studies were identified by searching electronic databases (MEDLINE and PubMed) and reference lists of respective articles. Only articles available in English were considered for this review. RESULTS: Brow ptosis and asymmetry are common adverse effects of botulinum toxin while the most common adverse effects associated with fillers are the local injection related effects manifesting as erythema, edema, pain, and ecchymosis. CONCLUSION: It is important that the treating physician is well verse with the various fillers and botulinum toxin complications and their management as some of the complications can be severely debilitating.

Facial Asymmetry in Unilateral Duane Retraction Syndrome.

SIGNIFICANCE: The overall objective of this study was to evaluate facial asymmetry in patients with unilateral Duane retraction syndrome (DRS). The results showed a high frequency of facial asymmetry parameters of the opposite side of head turn in unilateral DRS patients. PURPOSE: The purposes of this study were to evaluate the characteristics of facial asymmetry in unilateral exotropic and esotropic DRS and to compare the findings with orthotropic subjects. METHODS: This cross-sectional comparative case series study was performed in 44 consecutive patients with head turn caused by DRS and 44 orthotropic subjects from 2016 to 2019. Four pictures were taken from the patients' faces. The first and second pictures were taken when patients had head turn and when the head was completely straight for calculating the facial angle and relative facial size, respectively. The third and fourth pictures were taken when the head was positioned downward (to compare the size of the cheek) and upward (to evaluate nose asymmetry). RESULTS: The mean ± SD age of DRS patients and orthotropic subjects was 16.23 ± 9.92 and 20.68 ± 11.82 years, respectively. The frequency of facial asymmetry and all facial parameters (cheek compression, nasal tip and columella deviation, and compression of one of the nostrils) was significantly higher in DRS patients compared with orthotropic subjects (P < .001). In DRS patients with facial asymmetry, columella and nasal tip deviation (P = .006) and cheek and face compression (P = .03) were significantly more prevalent in the opposite direction of head turn. In the DRS group, the mean ± SD age of the patients with and without facial asymmetry was 17.37 ± 9.76 and 7.40 ± 6.54 years, respectively (P = .02). CONCLUSIONS: The frequency of facial asymmetry and all facial parameters was significantly higher in DRS patients compared with orthotropic subjects. In unilateral DRS patients, the face was more commonly affected on the opposite side of head turn.

Analysis of dental compensation in patients with facial asymmetry using cone-beam computed tomography.

INTRODUCTION: The purpose of this research was to evaluate dental compensation in facial asymmetry and its correlation with skeletal variables using cone-beam computed tomography. METHODS: Sixty adult patients were retrospectively divided into asymmetry (mean age, 21.8 ± 5.4 years) and symmetry groups (mean age, 28.1 ± 4.1 years); both groups comprised 30 patients. Independent and paired t tests were used for comparisons between the asymmetry and symmetry groups and between deviated (Dv) and nondeviated (NDv) sides of the asymmetry group, respectively. Pearson correlation between dental and skeletal variables was performed. RESULTS: The mean value of menton deviation was 9.4 mm in the asymmetry group. Compared with the symmetry group, the direction and amount of dental compensation of the asymmetry group were as follows: 2.5-mm extrusion of the maxillary first molar (UM6) at NDv (P <0.05); 1.8-mm higher position of the mandibular canine (LC) from the mandibular horizontal plane using mental foramen (MHP_mf) at NDv (P <0.05); 6°-more buccoversion of UM6 at Dv; 3.7°-more linguoversion of UM6 at NDv; 4.8°-more buccoversion of the maxillary canine (UC) at Dv; 4.9°-more buccoversion of the mandibular molar (LM6) at NDv; and 2.6°-more linguoversion of LC at Dv. Dental compensation correlated or marginally correlated with skeletal variables of the deviated mandible. CONCLUSIONS: Dental compensations, extrusion of the maxillary molars on the NDv, and buccal tipping of the maxillary teeth and lingual tipping of the mandibular teeth on the Dv, were observed. The mandibular body length was associated with linguoversion of the mandibular molars on the Dv. The ramal inclination was related to the extrusion of the maxillary molars on the NDv.

Orofacial functions and quality of life in children with unilateral cleft lip and palate.

This study aimed to evaluate the orofacial functions and oral health-related quality of life (OHRQoL) of children with unilateral cleft lip and palate (UCLP). This case-control study included patients with UCLP matched by sex and age with controls (children without UCLP), resulting in the inclusion of a total of 108 eight- to ten-year-old children. Orofacial functions and OHRQoL were evaluated using the Nordic Orofacial Test-Screening (NOT-S) and the Child Perceptions Questionnaire (CPQ 8-1 0 ), respectively. Data normality was assessed by the Kolmogorov-Smirnov test. Differences and correlations in NOT-S and CPQ 8-1 0 scores between and within the groups were evaluated using Mann-Whitney and Spearman´s correlation tests, respectively. The distribution of NOT-S and global ratings of CPQ 8-1 0 for each group were assessed by Chi-squared/Fisher's Exact tests. The UCLP group had a higher NOT-S total and examination scores than the controls. Dysfunctions related to breathing, facial symmetry/expression, and speech were more frequent in the UCLP patients than in the controls. The UCLP group had higher scores on the social well-being domain than the controls. There was a significant difference between the groups in their ratings in regards to the extent to which their oral condition affected their life overall, with controls perceiving it as somewhat better than patients. In both groups, NOT-S total and interview scores were positively correlated with CPQ 8-1 0 total and domain scores. The NOT-S examination score was only significantly correlated with social domain scores in the control group. The presence of UCLP was associated with clinical signs of orofacial dysfunctions related to breathing, facial symmetry/expression, and speech. Children with UCLP reported more orofacial dysfunctions and negative impacts on social well-being than controls.

Increased facial asymmetry in autism spectrum conditions is associated with symptom presentation.

A key research priority in the study of autism spectrum conditions (ASC) is the discovery of biological markers that may help to identify and elucidate etiologically distinct subgroups. One physical marker that has received increasing research attention is facial structure. Although there remains little consensus in the field, findings relating to greater facial asymmetry (FA) in ASC exhibit some consistency. As there is growing recognition of the importance of replicatory studies in ASC research, the aim of this study was to investigate the replicability of increased FA in autistic children compared to nonautistic peers. Using three-dimensional photogrammetry, this study examined FA in 84 autistic children, 110 typically developing children with no family history of the condition, and 49 full siblings of autistic children. In support of previous literature, significantly greater depth-wise FA was identified in autistic children relative to the two comparison groups. As a further investigation, increased lateral FA in autistic children was found to be associated with greater severity of ASC symptoms on the Autism Diagnostic Observation Schedule, second edition, specifically related to repetitive and restrictive behaviors. These outcomes provide an important and independent replication of increased FA in ASC, as well as a novel contribution to the field. Having confirmed the direction and areas of increased FA in ASC, these findings could motivate a search for potential underlying brain dysmorphogenesis. Autism Res 2019, 12: 1774-1783. © 2019 International Society for Autism Research, Wiley Periodicals, Inc. LAY SUMMARY: This study looked at the amount of facial asymmetry (FA) in autistic children compared to typically developing children and children who have siblings with autism. The study found that autistic children, compared to the other two groups, had greater FA, and that increased FA was related to greater severity of autistic symptoms. The face and brain grow together during the earliest stages of development, and so findings of facial differences in autism might inform future studies of early brain differences associated with the condition.

Orofacial functions and quality of life in children with unilateral cleft lip and palate

Abstract This study aimed to evaluate the orofacial functions and oral health-related quality of life (OHRQoL) of children with unilateral cleft lip and palate (UCLP). This case-control study included patients with UCLP matched by sex and age with controls (children without UCLP), resulting in the inclusion of a total of 108 eight- to ten-year-old children. Orofacial functions and OHRQoL were evaluated using the Nordic Orofacial Test-Screening (NOT-S) and the Child Perceptions Questionnaire (CPQ 8-1 0 ), respectively. Data normality was assessed by the Kolmogorov-Smirnov test. Differences and correlations in NOT-S and CPQ 8-1 0 scores between and within the groups were evaluated using Mann-Whitney and Spearman´s correlation tests, respectively. The distribution of NOT-S and global ratings of CPQ 8-1 0 for each group were assessed by Chi-squared/Fisher's Exact tests. The UCLP group had a higher NOT-S total and examination scores than the controls. Dysfunctions related to breathing, facial symmetry/expression, and speech were more frequent in the UCLP patients than in the controls. The UCLP group had higher scores on the social well-being domain than the controls. There was a significant difference between the groups in their ratings in regards to the extent to which their oral condition affected their life overall, with controls perceiving it as somewhat better than patients. In both groups, NOT-S total and interview scores were positively correlated with CPQ 8-1 0 total and domain scores. The NOT-S examination score was only significantly correlated with social domain scores in the control group. The presence of UCLP was associated with clinical signs of orofacial dysfunctions related to breathing, facial symmetry/expression, and speech. Children with UCLP reported more orofacial dysfunctions and negative impacts on social well-being than controls.

Facial Asymmetry-Based Age Group Estimation: Role in Recognizing Age-Separated Face Images.

Face recognition aims to establish the identity of a person based on facial characteristics. On the other hand, age group estimation is the automatic calculation of an individual's age range based on facial features. Recognizing age-separated face images is still a challenging research problem due to complex aging processes involving different types of facial tissues, skin, fat, muscles, and bones. Certain holistic and local facial features are used to recognize age-separated face images. However, most of the existing methods recognize face images without incorporating the knowledge learned from age group estimation. In this paper, we propose an age-assisted face recognition approach to handle aging variations. Inspired by the observation that facial asymmetry is an age-dependent intrinsic facial feature, we first use asymmetric facial dimensions to estimate the age group of a given face image. Deeply learned asymmetric facial features are then extracted for face recognition using a deep convolutional neural network (dCNN). Finally, we integrate the knowledge learned from the age group estimation into the face recognition algorithm using the same dCNN. This integration results in a significant improvement in the overall performance compared to using the face recognition algorithm alone. The experimental results on two large facial aging datasets, the MORPH and FERET sets, show that the proposed age group estimation based on the face recognition approach yields superior performance compared to some existing state-of-the-art methods.

Temporomandibular Joint Ankylosis: Algorithm of Treatment.

: Temporomandibular joint ankylosis, according to age of onset, causes severe functional and morphological disorders, as well as stunted craniofacial growth and development.The primary goal of treatment is to resolve the functional and morphological disorders. METHOD: Pre- and posttreatment clinical and cephalometric registries were conducted in 15 patients with temporomandibular joint ankylosis over a 10-year period (2002-2012). All the patients underwent complete removal of the ankylotic block, gap arthroplasty, and ipsilateral coronoidectomy. Distraction osteogenesis was performed on 12 patients. RESULTS: Fifteen patients, 8 female and 7 male, ranging from 3 to 30 years of age, were included in this study. The posttreatment follow-up period ranged from 3 to 13 years.The mean preoperative maximum mouth opening was 3 ± 1.7 mm, and the mean postoperative maximum mouth opening was 36 ± 6.5 mm. The labial inclination with respect to the true horizontal decreased considerably (6.2° ± 2.3° preoperative to 1° ± 1.6° postoperative). A correction of the mandibular deviation was measured at the symphysis with respect to the facial midline (8° ± 2° preoperative to 2° postoperative). Finally, the height ratio of both mandibular rami (the healthy side and the affected side) decreased considerably (1.27 ± 0.05 preoperative to 1.07 ± 0.06 postoperative).Reankylosis only occurred in 2 patients, who were then successfully treated by means of gap arthroplasty. CONCLUSIONS: The therapeutic algorithm proposed in the present work provides favorable functional and morphological results. Early and aggressive functional physiotherapy is essential to minimize the risk of reankylosis.

Facial Expressiveness in Infants With and Without Craniofacial Microsomia: Preliminary Findings.

OBJECTIVE: To compare facial expressiveness (FE) of infants with and without craniofacial macrosomia (cases and controls, respectively) and to compare phenotypic variation among cases in relation to FE. DESIGN: Positive and negative affect was elicited in response to standardized emotion inductions, video recorded, and manually coded from video using the Facial Action Coding System for Infants and Young Children. SETTING: Five craniofacial centers: Children's Hospital of Los Angeles, Children's Hospital of Philadelphia, Seattle Children's Hospital, University of Illinois-Chicago, and University of North Carolina-Chapel Hill. PARTICIPANTS: Eighty ethnically diverse 12- to 14-month-old infants. MAIN OUTCOME MEASURES: FE was measured on a frame-by-frame basis as the sum of 9 observed facial action units (AUs) representative of positive and negative affect. RESULTS: FE differed between conditions intended to elicit positive and negative affect (95% confidence interval = 0.09-0.66, P = .01). FE failed to differ between cases and controls (ES = -0.16 to -0.02, P = .47 to .92). Among cases, those with and without mandibular hypoplasia showed similar levels of FE (ES = -0.38 to 0.54, P = .10 to .66). CONCLUSIONS: FE varied between positive and negative affect, and cases and controls responded similarly. Null findings for case/control differences may be attributable to a lower than anticipated prevalence of nerve palsy among cases, the selection of AUs, or the use of manual coding. In future research, we will reexamine group differences using an automated, computer vision approach that can cover a broader range of facial movements and their dynamics.

Facial skeleton asymmetry and its relationship to mastication in the Early Medieval period (Great Moravian Empire, Mikulcice, 9th-10th century).

OBJECTIVES: The aim of this study was to analyse the relationship of mastication and directional asymmetry (DA) of upper facial skeleton in Early Medieval sample from the Mikulcice settlement (Czech Republic). DESIGN: The settlement is divided into two burial areas of presumably different socioeconomic status: the castle and the sub-castle. The material consisted of 193 individuals (125 castle, 68 sub-castle). The relationship of facial skeleton DA and mastication was analysed by examining tooth wear and mandibular shape by means of 3D geometric morphometrics. Tooth wear of premolars and molars was evaluated using appropriate scoring systems. 3D coordinates of 35 mandibular landmarks were scanned using MicroScribe G2X digitizing system. RESULTS: The results did not reveal any significant differences in tooth wear DA or mandible DA values between burial areas or sexes. Mandibular shape, however, differed significantly between burial areas and sexes. Directional changes of mandibular landmarks supported a right chewing side preference in the sample. Significant relationship between upper facial skeleton DA and mandible DA was recorded. CONCLUSIONS: Differences in subsistence between burial areas and sexes did not translate into differences in mandible DA and dental wear. However, mandibular shape analysis revealed prominence of areas affected by masticatory muscles in individuals from the castle. Higher consumption of tough material, such as meat, has been proposed as possible explanation. The right side was found to be preferential for chewing. The relationship between upper facial skeleton DA and mandible DA was concluded to be the result of the compensatory and adaptive function of mandible.

Surface electromyography before and after orthognathic surgery and condylectomy in active laterognathia: a case report.

BACKGROUND: Condylar hyperplasia is a rare bone disease characterised by excessive development of mandibular condyle, which can lead to the development of asymmetric facial deformity together with malocclusion, mandibular deviation, TMJ and masticatory musculoskeletal system dysfunction. There is not a treatment protocol universally accepted. In order to determine the correct management, treatment and intervention timing of these patients, morphological examinations should be coupled with functional assessments. CASE REPORT: In the present case report, morphological (bone scintigraphy; orthopantomography; posteroanterior and lateral cephalograms; 3D facial photographs) and functional (surface electromyography of masseter and temporalis muscles) quantitative data of a 20-year-old male patient affected by unilateral condylar hyperplasia are presented. The patient underwent a surgical treatment with high unilateral condylectomy associated to a maxillary Le Fort I osteotomy; as well as orthodontic treatment before and after surgery. Facial morphology and masticatory muscles activity were assessed before surgery and followed-up 6, 12 and 24 months after surgery. Twenty-four months after surgery, all electromyographic values were normal, and soft-tissue facial asymmetry was negligible at 3D assessment. CONCLUSION: Surface electromyography joins a set of clinical and morphological diagnostic tests that help the surgeon in planning the operation and managing the post-surgical patient.

Relationship between the degree and direction of nasal septum deviation and nasal bone morphology.

BACKGROUND: Nasal septal deviation may affect nasal bone growth and facial morphology. Knowledge of nasal morphologic parameters may plays an important role in planning successful rhinoplasty and septoplasty operation. The aim of our study was to evaluate the relationship between the direction and degree of nasal septal deviation with nasal bone morphology, along with factors such as age and gender. METHODS: Maxillofacial computed tomography (CT) of 250 patients with nasal septal deviation was analyzed retrospectively in this study. We excluded patients with factors that could affect their nasal bone morphology, and a total of 203 patients (111 males, 92 females; mean age, 36.23 years; age range, 18-79 years) were evaluated. The nasal deviation angle was measured on coronal CT images as the angle between the most deviated point of the septum, and the midline nasal morphology was determined by measuring nasal length, internasal angle and lateral and intermediate nasal thickness on both sides. RESULTS: The deviation of nasal septum has been detected as to the right in 107 patients (52.7%) and to the left in 96 patients (47.3%). Lateral and intermediate nasal bone thickness and nasal bone length were significantly greater on the ipsilateral deviation side (Table 3). No significant correlation was found between the variation of the nasal deviation angle and nasal bone morphology (Table 4). There were significant differences between the sexes for all investigated parameters except for the nasal deviation angle (p = 0.660). We found that the only internasal angle increases with aging (p = 0.002). CONCLUSION: The study shows that the direction of nasal septal deviation may be a factor that affects nasal bone morphology.

Maxillofacial features and systemic malformations in expanded spectrum Hemifacial Microsomia.

Hemifacial microsomia (HFM) is a rare, multisystemic congenital disease with estimated frequency of 1/26370 births in Europe. Most cases are sporadic and caused by unilateral abnormal morphogenesis of the first and second pharyngeal arches. The aim of this study is to define the types and frequency of maxillofacial and systemic malformations in HFM patients. This is a case series study of patients with HFM evaluated at a single institution. Data were acquired through history, physical examination, photographs, diagnostic radiology, and laboratory and analyzed by the FileMakerPro database on 95 patients (54F; 41M) of which 89 met the inclusion criteria. Mandibular hypoplasia was observed in 86 patients with right-side preponderance (50). One patient had bilateral mandibular hypoplasia. Seventy-four had external ear anomalies (anotia or microtia). Eleven had bilateral malformed ears. Hearing impairment, associated with stenosis or atresia of the external ear canal, was found in 69 patients (eight with bilateral canal defects). Ocular anomalies were seen in 41 (23 with dermoid cysts) and 39 had orbital malformations. Facial nerve paralysis was observed in 38 patients. Cleft lip/palate (10), preauricular tags (55), and macrostomia (41) were also described. A total of 73/86 had systemic malformations, mainly vertebral (40), genitourinary (25), and cardiovascular (28). Sixteen had cerebral anomalies (four with intellectual disability). All patients suspected of HFM should undergo a complete systematic clinical and imaging investigation to define the full scope of anomalies. Since the disease is rare and complex, affected patients should be monitored by specialized multidisciplinary team centers.

Three-dimensional surgical simulation improves the planning for correction of facial prognathism and asymmetry: A qualitative and quantitative study.

Traditional planning method for orthognathic surgery has limitations of cephalometric analysis, especially for patients with asymmetry. The aim of this study was to assess surgical plan modification after 3-demensional (3D) simulation. The procedures were to perform traditional surgical planning, construction of 3D model for the initial surgical plan (P1), 3D model of altered surgical plan after simulation (P2), comparison between P1 and P2 models, surgical execution, and postoperative validation using superimposition and root-mean-square difference (RMSD) between postoperative 3D image and P2 simulation model. Surgical plan was modified after 3D simulation in 93% of the cases. Absolute linear changes of landmarks in mediolateral direction (x-axis) were significant and between 1.11 to 1.62 mm. The pitch, yaw, and roll rotation as well as ramus inclination correction also showed significant changes after the 3D planning. Yaw rotation of the maxillomandibular complex (1.88 ± 0.32°) and change of ramus inclination (3.37 ± 3.21°) were most frequently performed for correction of the facial asymmetry. Errors between the postsurgical image and 3D simulation were acceptable, with RMSD 0.63 ± 0.25 mm for the maxilla and 0.85 ± 0.41 mm for the mandible. The information from this study could be used to augment the clinical planning and surgical execution when a conventional approach is applied.