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PubMed2005

Combining psychometric and biometric measures of substance use.

This paper examines the need, feasibility, and validity of combining two biometric (urine and saliva) and three self-report (recency, peak quantity, and frequency) measures of substance use for marijuana, cocaine, opioids, and other substances (including alcohol and other drugs). Using data from 337 adults with substance dependence, we used structural equation modeling to demonstrate that these multiple measures are driven by the same underlying factor (substance use) and that no single measure is without error. We then compared the individual measures and several possible combinations of them (including one based on the latent factors and another based on the Global Appraisal of Individual Needs (GAIN) Substance Frequency Scale) to examine how well each predicted a wide range of substance-related problems. The measure with the highest construct validity in these analyses varied by drug and problem. Despite their advantages for detection, biometric measures were frequently less sensitive to the severity of other problems. Composite measures based on the substance-specific latent factors performed better than simple combinations of the biometric and psychometric measures. The Substance Frequency Scale from the GAIN performed as well as or better than all measures across problem areas, including the latent factor for any use. While the research was limited in some ways, it has important implications for the ongoing debate about the proper way to combine biometric and psychometric data.

Adolescent↗
PubMed2005

Bayesian analysis of fingerprint, face and signature evidences with automatic biometric systems.

The Bayesian approach provides a unified and logical framework for the analysis of evidence and to provide results in the form of likelihood ratios (LR) from the forensic laboratory to court. In this contribution we want to clarify how the biometric scientist or laboratory can adapt their conventional biometric systems or technologies to work according to this Bayesian approach. Forensic systems providing their results in the form of LR will be assessed through Tippett plots, which give a clear representation of the LR-based performance both for targets (the suspect is the author/source of the test pattern) and non-targets. However, the computation procedures of the LR values, especially with biometric evidences, are still an open issue. Reliable estimation techniques showing good generalization properties for the estimation of the between- and within-source variabilities of the test pattern are required, as variance restriction techniques in the within-source density estimation to stand for the variability of the source with the course of time. Fingerprint, face and on-line signature recognition systems will be adapted to work according to this Bayesian approach showing both the likelihood ratios range in each application and the adequacy of these biometric techniques to the daily forensic work.

Bayes Theorem↗
PubMed2001

Optical and biometric relationships of the isolated pig crystalline lens.

AIM: To investigate the interrelationships between optical and biometric properties of the porcine crystalline lens, to compare these findings with similar relationships found for the human lens and to attempt to fit this data to a geometric model of the optical and biometric properties of the pig lens. METHODS: Weight, focal length, spherical aberration, surface curvatures, thickness and diameters of 20 isolated pig lenses were measured and equivalent refractive index was calculated. These parameters were compared and used to geometrically model the pig lens. RESULTS: Linear relationships were identified between many of the lens biometric and optical properties. The existence of these relationships allowed a simple geometrical model of the pig lens to be calculated which offers predictions of the optical properties. CONCLUSIONS: The linear relationships found and the agreement observed between measured and modeled results suggest that the pig lens confirms to a predictable, preset developmental pattern and that the optical and biometric properties are predictably interrelated.

Animals↗
PubMed2004

[Comparison of the optical coherence method (Zeiss IOL-Master) with two ultrasonographic biometric methods for the calculation of posterior chamber intraocular lenses after phacoemulsification as part of clinical routine].

BACKGROUND: The aim of this work was to investigate the accuracy of prediction of three different biometric methods for the calculation of posterior chamber intraocular lenses. METHODS: In 59 consecutive patients who underwent extracapsular cataract-extraction with posterior chamber intraocular lens implantation, we compared the refractive results at the first day (D1) and 6 weeks (W6) after surgery with the calculated refraction of three biometric methods: the Carl Zeiss "IOL-Master 99" (IOLM), the Biovision "Echograph Class 1 - Type B" (BIOV) and the Allergan Humphrey "Ultrasonic Biometer Mod. 820" (AHUB). For statistical calculation box-plots, the Wilcoxon signed-rank test and linear regression analysis were used. RESULTS: In all patients the mean of the postoperative refraction was - 0.07 D (SD: 1.41) at day 1 and 0.12 D (SD: 1.18) at week 6. Compared to the postoperative refraction at week 6, the calculated refractive values were higher in all three measuring devices: IOLM: + 0.28 D (SD: 0.67), BIOV: + 0.60 D (SD: 0.88), AHUB: + 0.26 D (SD: 0.92). There were no statistically significant differences between IOLM and BIOV, or respectively, AHUB and BIOV (p < 0.0001), but a significant difference was found between IOLM and AHUB, (p = 0.906). To adjust for systematic differences of the agreement, one can calculate the postoperative refraction at week 6 (REF6) from IOLM by using the linear regression formula: REF6 = 1.1 x IOLM + 0.3. CONCLUSION: A comparison between the three biometric methods and the refractive results at day 1 and week 6 after cataract surgery with implantation of a posterior chamber intraocular lens showed that the calculated mean values obtained from the three biometric methods are higher than the real postoperative refraction. Calculations using the Zeiss IOL-Master and the Allergan Humphrey Ultrasonic Biometer are closer to the patient's postoperative refraction than calculations using the Biovision Echograph.

Aged↗
PubMed2006

Comparison of routine care self-reported and biometrical data on hypertension and diabetes: results of the Utrecht Health Project.

BACKGROUND: Information on the prevalence of diseases is commonly gathered by questionnaires. Although the method is relatively inexpensive and efficient as opposed to physical examinations, the validity of the information collected is often questioned. The objective of this study was to assess the value of biometrical data complementary to self-reported questionnaire information for estimating the prevalence of hypertension and diabetes in the population at large and to examine factors that affect the accuracy of self-reporting. METHODS: Baseline data of 4950 adult participants of the Utrecht Health Project, a community-based prospective cohort study, were used to calculate sensitivity and specificity of self-reported hypertension and diabetes with the results of blood pressure measurements and blood glucose levels, corrected for current medication use, as the reference standard. Multivariate logistic regression analysis was performed to determine which participants' characteristics independently predicted the accuracy of self-reports. RESULTS: Overall sensitivity was 34.5% for self-reported data on hypertension and 58.9% for diabetes, while overall specificity was high for both conditions (96.4 and 99.4%, respectively). The agreement between self-reported and biometrical data was higher for diabetes than for hypertension and varied per subgroup. CONCLUSIONS: The use of self-reported data to estimate the prevalence of hypertension and diabetes may lead to underestimated prevalence estimates and biased associations with risk factors due to differential misclassification. Adding biometrical measurements to self-reported questionnaire information will assure the validity of the data. The magnitude of the additional value of biometrical data depends on the condition studied and the characteristics of the population under investigation.

Adolescent↗
PubMed1993

Anatomic features of the carpal scaphoid: validation of biometric measurements and symmetry with three-dimensional MR imaging.

The goals of reconstructive surgery for scaphoid fracture nonunions include restoration of normal scaphoid length and shape by use of the contralateral scaphoid bone as a geometric model. A literature search revealed limited documentation of normal biometric measurements and no validation of scaphoid anatomic symmetry. A study was performed to provide normative data and evaluate the right-to-left symmetry of specific geometric measurements of the scaphoid. One hundred normal carpal scaphoid bones in 30 healthy subjects and 40 patients were examined with three-dimensional magnetic resonance (MR) imaging. Standardized oblique projections were reconstructed from each three-dimensional data set, and seven biometric measurements of each scaphoid were obtained. Normative data from the study group were obtained by means of analysis of all 100 scaphoids. Right-to-left symmetry was validated with the biometric measurements of both scaphoids in the healthy subjects. These data validate scaphoid symmetry and provide 95% confidence intervals for specific biometric measurements that are used for preoperative planning of surgical reconstruction of scaphoid nonunions.

Adolescent↗
PubMed1991

[On factors related to the width of anterior chamber angle--multivariate analysis of biometrically determined values].

Primary angle-closure glaucoma (PACG) is associated with certain biometric ocular features such as shallow anterior chamber, axial hyperopia, increased thickness of the lens and small corneal diameter. The vast majority of previous studies on PAGG has shown that females are affected more frequently than males. In an attempt to study the relationship between the angle width and ocular dimensions, we carried out gonioscopic examination and biometric measurements (corneal diameter, corneal radius, anterior chamber depth, lens thickness, relative lens position and axial length) in 1,169 eyes of 585 adult subjects who participated in the glaucoma screening in Gifu Prefecture. It was found that the angle width significantly correlated with each biometric value. The coefficient of determination calculated by multiple regression analysis was 0.41, suggesting that factors other than these are involved in determining the angle width. When the angle width of females was compared to that of males with identical refractive errors and biometric values, the angle width of females was significantly narrower than that of males. Hence, the difference in ocular dimensions does not adequately explain the higher incidence of narrow angle in females. Increased asymmetry of angle width between a pair of eyes with aging appeared to be related to asymmetry of lens thickness, anterior chamber depth and lens position.

Adult↗
PubMed2003

Anatomic and biometric study of the acromioclavicular joint by ultrasound.

The aim of this study was to describe the normal ultrasound anatomy of acromioclavicular joint (ACJ) and to establish ultrasound biometric criteria of this joint. Thirty healthy volunteers (16 men, 14 women) underwent a bilateral ultrasound examination of the ACJ in both planes (superior, anterosuperior) by two different observers. Six measurements were evaluated on the ACJ. The morphological appearance was also studied. Five morphological types of the ACJ were identified. No significant biometric difference was found between the observers, the planes, the dominant and the non-dominant side, and between men and women (except for the deep joint space distance). However, the variability of the ACJ made this biometric study difficult. The maximum distance between the joint capsule and the deep joint space through the superior plane, seemed to be a reproducible measurement with the best confidence interval.

Acromioclavicular Joint↗
PubMed2004

A powerful combination: the use of positional scanning libraries and biometrical analysis to identify cross-reactive T cell epitopes.

Studies on the elucidation of the specificity of the T cell receptor (TCR) at the antigen and peptide level have contributed to the current understanding of T cell cross-reactivity. Historically, most studies of T cell specificity and degeneracy have relied on the determination of the effects on T cell recognition of amino acid changes at individual positions or MHC binding residues, and thus they have been limited to a small set of possible ligands. Synthetic combinatorial libraries (SCLs), and in particular positional scanning synthetic combinatorial libraries (PS-SCLs) represent collections of millions to trillions of peptides which allow the unbiased elucidation of T cell ligands that stimulate clones of both known and unknown specificity. PS-SCLs have been used successfully to study T cell recognition and to identify and optimize T cell clone (TCC) epitopes in infectious diseases, autoimmune disorders and tumor antigens. PS-SCL-based biometrical analysis represents a further refinement in the analysis of the data derived from the screening of a library with a TCC. It combines this data with information derived from protein sequence databases to identify natural peptide ligands. PS-SCL-based biometrical analysis provides a method for the determination of new microbial antigen and autoantigen sequences based solely on functional data rather than sequence homology or motifs, making the method ideally suited for the prediction and identification of both native and cross-reactive epitopes by virtue of its ability to integrate the examination of trillions of peptides in a systematic manner with all of the protein sequences in a given database. We review here the application of PS-SCLs and biometrical analysis to identify cross-reactive T cell epitopes, as well as the current efforts to refine this strategy.

Biometry↗
PubMed2004

[Biometric study of acute-angle-closure glaucoma using Orbscan and echography].

PURPOSE: To study acute-angle-closure glaucoma (AACG) biometry using Orbscan and echography. MATERIAL AND METHODS: We prospectively studied 200 normal eyes of 100 patients (including eyes with ametropia), 50 eyes of 25 patients before peripherial YAG laser iridotomy, 25 phakic eyes of 25 patients with a history of acute-angle-closure glaucoma (AACG) in the fellow eye. Both plane and polynomial modes of reconstruction of the iridocorneal angle measurement were analyzed. Biometric measurements of the three groups were compared. Biometric measurements (i.e., iridocorneal angle, anterior chamber depth, axial length, and lens thickness) and subjective spherical equivalent were correlated with the etiological classification. RESULTS: Age, sex, iridocorneal angle, anterior chamber depth, lens thickness, axial length and subjective spherical equivalent were significantly different in the three groups (p<0.002). The polynomial iridocorneal angle measurement was 43.4 degrees in the normal group, 36.5 degrees in the iridotomy group, and 28.4 degrees in the AACG group (p<0.001). Iridocorneal angle measurement correlated with the other biometric measurements (rs>0.51; p<0.001) and with the etiological classification (rs< or =0.68; p<0.001). The anterior chamber depth measurement obtained by Orbscan or echography was the best parameter for predicting ACCG (rs=0.77; p<0.001). CONCLUSION: The anterior chamber depth and polynimial iridocorneal angle obtained using the Orbscan device appears to be useful in predicting acute-angle-closure glaucoma.

Acute Disease↗
PubMed1997

The prevalence and biometric structure of pathological dissociation in the general population: taxometric and behavior genetic findings.

Taxometric and biometric analyses were conducted on 2 North American samples to investigate the prevalence and biometric structure of pathological dissociation. Results indicated that approximately 3.3% of the general population belongs to a pathological dissociative taxon. A brief 8-item self-report scale called the DES-T can be used to calculate taxon membership probabilities in clinical and nonclinical samples of adults (a SAS scoring program is provided for this purpose). The genetic and environmental architecture of pathological dissociative symptoms was explored by conducting a biometric analysis on DES-T ratings from 280 identical and 148 fraternal twins. The findings suggest that approximately 45% of the observed variance on the DES-T can be attributed to shared environmental influences. The remaining variance is due to nonshared environmental influences.

Adult↗
PubMed2002

Chiari-II malformation: a biometric analysis.

INTRODUCTION: Chiari-II malformation is a complex set of anatomic abnormalities of the posterior fossa, brainstem, and cerebellum seen in myelomeningocele. Previous studies have tried to understand this condition and its clinical consequences by studying a few fixed anatomic landmarks as dependent variables and clinical symptoms as outcome variables. These studies have led to conflicting and limited results. As a first step towards a more comprehensive study of the structural-functional relationships in Chiari-II malformation, we undertook a biometric case-series analysis of a group of individuals with MMC, using both traditional methods to study size, and thin-plate spline methodology to study shape. MATERIALS AND METHODS: The traditional analysis was a retrospective, randomly obtained case-series of 25 individuals with myelomeningocele and Chiari-II malformation. MRIs were digitized for biometric analysis of the component structures and compared to 25 controls. Landmarks on the digitized images were measured using Scion Image. Data were statistically analyzed using SPSS. The thin-plate spline analysis used a subset of these individuals (n = 14). Landmarks on digitized MRIs were identified and marked with TPSDig software. Landmark data was then imported into Splus to generate a series of shape variables. Statistical analysis using Splus was then undertaken. RESULTS: Traditional analysis revealed relationships between vermian herniation and pontomedullary junction position (p < 0.05) as well as between the height (and overall size) of the posterior fossa and degree of vermian herniation (p < 0.05). The degree of brainstem herniation/elongation did not correlate with the degree of vermian herniation. The shape analysis revealed that there is as much shape variability within the group of Chiari-II patients as there is between this group and unaffected controls. Thin-plate spline analysis shows that the position of the caudal-most aspect of the vermis is the point of greatest brain rearrangement; likewise, the opisthion is the point of greatest bony rearrangement. Partial least-squares analysis shows that in Chiari-II patients, a strong correlation (r = 0.821) exists between the extent to which the brain is warped (specifically, in regard to vermian descent) and the extent to which the bone is warped (specifically, in regard to the displacement of the opisthion) (p < 0.05). CONCLUSION: Traditional biometric analysis of size confirms that the degree of vermian herniation and cervicomedullary junction herniation are independent variables in Chiari-II malformation. Posterior fossa size is an important factor in explaining the variability of vermian herniation. The relationship between IPN position and vermian herniation suggests the possibility of a common etiology. The phenomenon of cervicomedullary junction descent appears to be independent, suggesting a different etiology. Analysis of shape indicated that shape changes in bone and brain are related, and that the Chiari-II-associated abnormalities vary greatly in their degree of abnormality. The extreme morphological variability argues against the use of mean differences as a statistical technique in analyzing morphological abnormalities in the structures we investigated.

Adolescent↗
PubMed2006

The Nepal Longitudinal Study: biometric characteristics of developing eyes.

PURPOSE: To identify differences in potential biometric markers for predicting refractive error in school children. METHODS: Biometric data on 895 Tibetan children, aged 6 to 18 years, residing in Katmandu, Nepal, were collected biennially from 1992 to 2000. Measurements included cycloplegic autorefraction, A-scan ultrasonography, and video phakometry. Only those children who had been studied at least once at age 12 years or more were included in the analysis. Subjects were divided into two groups: a myopia group if the refractive error was myopic by more than -0.50 D and a nonmyopia group if the refractive error was maximally myopic by -0.50 D, expressed as a spherical equivalent error in the left eye. RESULTS: Biometric measures that differed significantly with increasing age between the two refractive groups included: anterior chamber depth + 0.012 mm/year (p = 0.014), anterior lens radius of curvature + 0.073 mm/year (p = 0.001), lens power -0.059 D/year (p = 0.082), lens thickness -0.005 mm/year (p = 0.02), and vitreous chamber depth + 0.084 mm/year (p < 0.001). Corneal radii of curvature of the myopic group were steeper at all ages by 0.09 mm (p < 0.001), but the rate of change with age was equivalent across the refractive groups. CONCLUSIONS: Compared with those who remained nonmyopic, children who developed myopia had a crystalline lens that was initially thicker and steeper, and a vitreous chamber that was initially shorter. With age, children who became myopic developed greater lens thinning, greater flattening of the anterior lens surface radius, and a greater increase in vitreous chamber depth than their nonmyopic counterparts.

Adolescent↗
PubMed2006

Automated biometrics-based personal identification of the Hunter-Schreger bands of dental enamel.

The use of automated biometrics-based personal identification systems is a ubiquitous procedure in present times. Biometrics has certain limitations, such as in cases when bodies are decomposed, burned, or only small fragments of calcified tissues remain. Dental enamel is the most mineralized tissue of organisms and resists post-mortem degradation. It is characterized by layers of prisms of regularly alternating directions, known as Hunter-Schreger bands (HSB). In this article, we show that the pattern variation of the HSB, referred here as toothprint, can be used as a biometric-based parameter for personal identification in automated systems.

Biometry↗
PubMed2006

Linear relationship of refractive and biometric lenticular changes during accommodation in emmetropic and myopic eyes.

AIM: Aim of this study was to investigate the relationship between refractive changes in the eye and biometric changes of the human crystalline lens during accommodation. Furthermore, differences in these relationships between young, healthy emmetropic and myopic subjects were analyzed. METHODS: Mean relative change in anterior chamber depth (ACD), lens thickness (LT), anterior segment length (ASL = ACD + LT) and in objective refraction were simultaneously assessed during near-point-induced accommodation in 10 emmetropic and 10 myopic subjects. Via a beam splitter, measurements were performed simultaneously using partial coherence interferometry (PCI) and infrared (IR) photorefraction. RESULTS: On average, for each diopter of accommodation LT increased by 0.063 mm in emmetropic and by 0.072 mm in myopic eyes, and ACD decreased by 0.047 mm and 0.057 mm, respectively. Mean ASL, indicating the position of the posterior lens pole, increased by 0.009 mm in emmetropic and by 0.013 mm in myopic eyes. The correlation between refractive and biometric changes was found to be essentially linear in both subgroups. Differences in ACD between emmetropic and myopic eyes were statistically significant at an accommodative stimulus of -1 D (p<0.04) and -2 D (p<0.02). CONCLUSION: The biometric and refractive changes of the human lens are highly correlated and linear in function in both emmetropic and myopic eyes.

Accommodation, Ocular↗
PubMed1999

Does convergence, not accommodation, cause axial-length elongation at near? A biometric study in teens.

To determine whether convergence rather than accommodation has a primary effect on the changes in axial length and other biometric components during near fixation, we measured the anterior chamber depth, lens thickness, vitreous length and axial length in the right eyes of 124 young male subjects while their left eyes focused at distance (6 m) and near (20 cm). The measurements were performed before and after cycloplegia in the right eye, so we aimed to study biometric components of the eye in the states of accommodation and nonaccommodation, but converging at near. While the left eye focused at near, the axial length increased significantly with and without cycloplegia (p < 0.0005 and p < 0.0005). The vitreous length was the main increasing ocular biometric component at near both with and without cycloplegia (p < 0.044 and p = 0.001, respectively). At near, there was no difference between two mean axial length and two vitreous length measurements both with and without cycloplegia (p = 0.672 and p = 0.595, respectively). Under cycloplegia, anterior chamber depth also increased significantly at near fixation (p = 0. 012). Axial elongation at near fixation, mainly due to an increase in vitreous length, may result from the effect of accommodative convergence rather than accommodation itself. Much use of convergence, not accommodation, may be one of the contributing factors in adult onset and adult progression of myopia.

Accommodation, Ocular↗
PubMed2004

Dependency of magnetocardiographically determined fetal cardiac time intervals on gestational age, gender and postnatal biometrics in healthy pregnancies.

BACKGROUND: Magnetocardiography enables the precise determination of fetal cardiac time intervals (CTI) as early as the second trimester of pregnancy. It has been shown that fetal CTI change in course of gestation. The aim of this work was to investigate the dependency of fetal CTI on gestational age, gender and postnatal biometric data in a substantial sample of subjects during normal pregnancy. METHODS: A total of 230 fetal magnetocardiograms were obtained in 47 healthy fetuses between the 15th and 42nd week of gestation. In each recording, after subtraction of the maternal cardiac artifact and the identification of fetal beats, fetal PQRST courses were signal averaged. On the basis of therein detected wave onsets and ends, the following CTI were determined: P wave, PR interval, PQ interval, QRS complex, ST segment, T wave, QT and QTc interval. Using regression analysis, the dependency of the CTI were examined with respect to gestational age, gender and postnatal biometric data. RESULTS: Atrioventricular conduction and ventricular depolarization times could be determined dependably whereas the T wave was often difficult to detect. Linear and nonlinear regression analysis established strong dependency on age for the P wave and QRS complex (r2 = 0.67, p < 0.001 and r2 = 0.66, p < 0.001) as well as an identifiable trend for the PR and PQ intervals (r2 = 0.21, p < 0.001 and r2 = 0.13, p < 0.001). Gender differences were found only for the QRS complex from the 31st week onward (p < 0.05). The influence on the P wave or QRS complex of biometric data, collected in a subgroup in whom recordings were available within 1 week of birth, did not display statistical significance. CONCLUSION: We conclude that 1) from approximately the 18th week to term, fetal CTI which quantify depolarization times can be reliably determined using magnetocardiography, 2) the P wave and QRS complex duration show a high dependency on age which to a large part reflects fetal growth and 3) fetal gender plays a role in QRS complex duration in the third trimester. Fetal development is thus in part reflected in the CTI and may be useful in the identification of intrauterine growth retardation.

Journal Article↗
PubMed2004

Iris recognition as a biometric method after cataract surgery.

BACKGROUND: Biometric methods are security technologies, which use human characteristics for personal identification. Iris recognition systems use iris textures as unique identifiers. This paper presents an analysis of the verification of iris identities after intra-ocular procedures, when individuals were enrolled before the surgery. METHODS: Fifty-five eyes from fifty-five patients had their irises enrolled before a cataract surgery was performed. They had their irises verified three times before and three times after the procedure, and the Hamming (mathematical) distance of each identification trial was determined, in a controlled ideal biometric environment. The mathematical difference between the iris code before and after the surgery was also compared to a subjective evaluation of the iris anatomy alteration by an experienced surgeon. RESULTS: A correlation between visible subjective iris texture alteration and mathematical difference was verified. We found only six cases in which the eye was no more recognizable, but these eyes were later reenrolled. The main anatomical changes that were found in the new impostor eyes are described. CONCLUSIONS: Cataract surgeries change iris textures in such a way that iris recognition systems, which perform mathematical comparisons of textural biometric features, are able to detect these changes and sometimes even discard a pre-enrolled iris considering it an impostor. In our study, re-enrollment proved to be a feasible procedure.

Algorithms↗