Biomedical subjects

F L Bookstein

Publications and source records attributed to F L Bookstein.

At least 37 records · Page 2Linked to original sources

PubMed1999

Individual differences in auditory and visual attention among fetal alcohol-affected adults.

BACKGROUND: Deficits in attention are commonly identified among patients who have been prenatally exposed to alcohol, and they often affect the ability of the patients to function appropriately in society. METHODS: Eleven adult patients with fetal alcohol syndrome (FAS) or fetal alcohol effects (FAE) were compared with nine adult subjects with no history of prenatal alcohol exposure, using four tests of visually and auditorially mediated attention. RESULTS: In relation to the comparison group, patients with FAS/FAE exhibited substantial deficits in both auditory and visual attention; the auditory deficits were greater. We observed two predominant patterns of deficits among patients with FAS/FAE, one involving both auditory and visual attention problems and the other involving less severe auditory problems and even fewer visual problems. Most subjects with FAS or FAE had some manifestations of attention problems in at least one of the tests of attention used in this study. We present a new graphical representation of individual auditory Continuous Performance Test data across a 6-min period, which, compared with conventional scores, more clearly reveals the markedly disrupted and variable attention patterns displayed by some individuals with FAS or FAE. CONCLUSIONS: These findings suggest that detailed analysis of the pattern of individual performance for each subject is an important aspect of Continuous Performance Test assessment. Our findings further suggest that intellectual performance (intelligence quotient score) alone is not sufficient to account for the patterns of disrupted attention for individuals with FAS/FAE. Assessment of individuals with FAS or FAE should include measurement of attentional functioning in both the visual and auditory modalities.

Adult↗

PubMed1998

Average African American three-dimensional computed tomography skull images: the potential clinical importance of ethnicity and sex.

The production of average 'normative' three-dimensional (3D) computed tomography surface images of the bony skull has only recently been explored. The authors wish to determine the effect of using sex- and ethnicity-specific adult average 3D skull images for comparisons with patient images at various stages of craniofacial surgical management (i.e., diagnosis, treatment planning, prosthetic design, image-guided operative procedures, and outcomes assessment). Craniofacial surgical reconstruction for abnormal patterns of development, cancer resection, or trauma are most likely to benefit from these comparisons. To morphometrically test the significance of separating normative 3D skull data by sex and ethnicity, the authors collected 52 3D, anatomical landmarks from 3D computed tomography scans of dry skulls of 20 Americans of European ethnicity and 20 Americans of primarily African (i.e., primarily African and some European) ethnicity. A Procrustes-based morphometric analysis of shape detects 1.2 times as much interethnic variance as intersex variance. The African American sample presents 4.2% more dolichocephaly, wider orbits, flatter nasal area, larger gnathic anatomy, and more procumbent dentition. Pooling the sexes across both groups, it is seen that men tend to have less bulbous crania, more protruding brows, noses, and masticatory muscle attachments, and relatively less protrusive palettes and anterior mandibles. Despite a small sample size (N = 40), the authors' results are statistically significant (P approximately 0.001 overall) for both of the main factors, sex and ethnicity, separately.

Adolescent↗

PubMed1998

A fetal alcohol behavior scale.

This research aimed to develop a Fetal Alcohol Behavior Scale (FABS) that describes the behavioral essence of fetal alcohol syndrome (FAS) and fetal alcohol effects (FAE), regardless of age, race, sex, and IQ. Using a reference sample of 472 diagnosed patients with FAS or FAE, ages 2 to 51, five studies are described. The FABS demonstrates high item-to-scale reliability (Cronbach's alpha = 0.91) and good test-retest reliability (r = 0.69) over an average interval of 5 years. It identifies many of the subjects with known or presumed prenatal alcohol exposure in detection studies using both prison and general samples. FABS scores also predict dependent living among adult patients with FAS/FAE. The FABS is uncorrelated with IQ, sex, age, race, and diagnosis (FAS versus FAE). We outline areas of further work to define the specificity and utility of this FABS.

Adolescent↗

PubMed1998

Prenatal alcohol exposure and family history of alcoholism in the etiology of adolescent alcohol problems.

OBJECTIVE: To examine the relative importance of prenatal alcohol exposure and family history of alcoholism for the prediction of adolescent alcohol problems. METHOD: In 1974-75, a population-based, longitudinal prospective study of alcohol and pregnancy began with self-report of alcohol use by pregnant women. In a 14-year follow-up, 439 parents provided information on the family history of alcohol problems for these adolescent offspring. The 14-year-old adolescents provided information on the frequency and quantity of their own alcohol consumption within the past month, on the consequences of their drinking over the past 3 years, and on their age at first intoxication. Additional covariates were assessed prenatally and at follow-up. RESULTS: Prenatal alcohol exposure was more predictive of adolescent alcohol use and its negative consequences than was family history of alcohol problems. Prenatal exposure retained a significant predictive effect even after adjustment for family history and other prenatal and environmental covariates. By contrast, the nominally significant correlation of family history with adolescent drinking is weaker after adjustment for prenatal alcohol exposure and disappears entirely after adjustment for other relevant covariates. We observed no evidence for an interactive effect of fetal exposure and family history in predicting adolescent alcohol use. CONCLUSIONS: Fetal alcohol exposure is a risk factor for adolescent alcohol involvement and alcohol-related problems and may account for variance in prediction of problems otherwise attributed to family history of alcoholism. Studies of alcoholism etiology and family history need to include consideration of even modest levels of fetal alcohol exposure.

Adolescent↗

PubMed1998

Neuropsychological deficits in adolescents with fetal alcohol syndrome: clinical findings.

Understanding the nature of cognitive deficits among adolescent patients with fetal alcohol syndrome (FAS) can direct future research on assessment and intervention. In an exploratory study, nine nonretarded teenagers with FAS were administered tests of IQ and adaptive behavior, and neuropsychological tests presumed sensitive to alcohol effects. Their performance was compared with psychometric norms and to data from a sample of 174 adolescents with minimal or no prenatal alcohol exposure. These nonretarded FAS patients commonly showed behavior problems, decreased social competence, and poor school performance. Neuropsychological testing revealed significant deficits, although no one neuropsychological profile characterized all patients and not all tests revealed problems. Relatively intact performance was observed in procedural memory, some measures of reaction time, and some reading measures. Deficits were seen on attentional and memory tasks tapping visual-spatial skills, short-term auditory attention and memory, declarative learning, and cognitive flexibility and planning. Difficulties in processing speed and accuracy were also seen. Comparison with a subgroup of 52 nonalcohol-exposed or minimally alcohol-exposed adolescents with a similar range of IQ scores demonstrated that deficits among these FAS patients were not fully explained by a general lowering of IQ.

Adolescent↗

PubMed1997

Incidence of fetal alcohol syndrome and prevalence of alcohol-related neurodevelopmental disorder.

We critique published incidences for fetal alcohol syndrome (FAS) and present new estimates of the incidence of FAS and the prevalence of alcohol-related neurodevelopmental disorder (ARND). We first review criteria necessary for valid estimation of FAS incidence. Estimates for three population-based studies that best meet these criteria are reported with adjustment for underascertainment of highly exposed cases. As a result, in 1975 in Seattle, the incidence of FAS can be estimated as at least 2.8/1000 live births, and for 1979-81 in Cleveland, approximately 4.6/1,000. In Roubaix, France (for data covering periods from 1977-1990), the rate is between 1.3 and 4.8/1,000, depending on the severity of effects used as diagnostic criteria. Utilizing the longitudinal neurobehavioral database of the Seattle study, we propose an operationalization of the Institute of Medicine's recent definition of ARND and estimate its prevalence in Seattle for the period 1975-1981. The combined rate of FAS and ARND is thus estimated to be at least 9.1/1,000. This conservative rate--nearly one in every 100 live births--confirms the perception of many health professionals that fetal alcohol exposure is a serious problem.

Female↗

PubMed1997

Landmark methods for forms without landmarks: morphometrics of group differences in outline shape.

Morphometrics, a new branch of statistics, combines tools from geometry, computer graphics and biometrics in techniques for the multivariate analysis of biological shape variation. Although medical image analysts typically prefer to represent scenes by way of curving outlines or surfaces, the most recent developments in this associated statistical methodology have emphasized the domain of landmark data: size and shape of configurations of discrete, named points in two or three dimensions. This paper introduces a combination of Procrustes analysis and thin-plate splines, the two most powerful tools of landmark-based morphometrics, for multivariate analysis of curving outlines in samples of biomedical images. The thin-plate spline is used to assign point-to-point correspondences, called semi-landmarks, between curves of similar but variable shape, while the standard algorithm for Procrustes shape averages and shape coordinates is altered to accord with the ways in which semi-landmarks formally differ from more traditional landmark loci. Subsequent multivariate statistics and visualization proceed mainly as in the landmark-based methods. The combination provides a range of complementary filters, from high pass to low pass, for effects on outline shape in grouped studies. The low-pass version is based on the spectrum of the spline, the high pass, on a familiar special case of Procrustes analysis. This hybrid method is demonstrated in a comparison of the shape of the corpus callosum from mid-sagittal sections of MRI of 25 human brains, 12 normal and 13 with schizophrenia.

Algorithms↗

PubMed1997

Association of prenatal alcohol exposure with behavioral and learning problems in early adolescence.

OBJECTIVE: To examine the association of moderate levels of prenatal alcohol exposure with learning and behavior in early adolescence. METHOD: A population-based cohort of 464 children were followed longitudinally from birth to age 14 years. Alcohol exposure was assessed via in-depth maternal self-report in the fifth month of pregnancy. At age 14, learning and behavior were assessed with multiple measures, tapping parent, teenager, and psychologist viewpoints, drawn from adolescent laboratory examination and parent phone interview. The underlying pattern of association between prenatal alcohol and adolescent outcome was detected using partial least-squares statistical techniques; confounding factors were dealt with by regression methods. RESULTS: Analyses revealed a statistically significant, subtle relationship between greater prenatal alcohol use and increased behavior/learning difficulties during adolescence, even after accounting for other developmental influences. "Binge" maternal drinking and exposure early in pregnancy were associated with a profile of adolescent antisocial behavior, school problems, and self-perceived learning difficulties. CONCLUSIONS: Fetal alcohol exposure (even at "social drinking" levels) is associated with developmental difficulties in adolescence that are consistent with problems seen earlier in life. Clinicians should understand the potential role prenatal alcohol exposure plays in behavioral and cognitive problems.

Adolescent↗

PubMed1996

Spatial relationships of neuroanatomic landmarks in schizophrenia.

Two new morphometric techniques, landmark-based shape analysis and landmark-based image averaging, were applied to magnetic resonance images (MRIs) to investigate the sites and extent of structural neuropathology in schizophrenia. These analyses allow the identification of averaged anatomy through joint registration on multiple landmarks simultaneously. MRI scans obtained in the midsagittal plane were compared between 14 patients with schizophrenia and 14 normal subjects. The relation between averaged landmark configuration in the two groups was visualized as a deformation. There were no large-scale shape abnormalities noted, although the patients had significantly smaller brains. The data suggest that the neuroanatomic abnormality associated with schizophrenia, in the midsagittal plane, is circumscribed (focal), involving primarily the region of the posterior corpus callosum, upper brainstem, and quadrigeminal cistern. Also, the thickness of the corpus callosum is reduced all along its length. The findings are consistent with prior studies suggesting involvement in schizophrenia of the cerebellum, the corpus callosum and, possibly, the limbic structures contributing to the corpus callosum. The methods of image averaging and shape analysis used in this study complement the 'region of interest' method of investigating morphometric abnormalities by characterizing the precise locations and spatial relationships among relevant structural brain abnormalities in schizophrenia.

Adult↗

PubMed1996

Spatial pattern analysis of functional brain images using partial least squares.

This paper introduces a new tool for functional neuroimage analysis: partial least squares (PLS). It is unique as a multivariate method in its choice of emphasis for analysis, that being the covariance between brain images and exogenous blocks representing either the experiment design or some behavioral measure. What emerges are spatial patterns of brain activity that represent the optimal association between the images and either of the blocks. This process differs substantially from other multivariate methods in that rather than attempting to predict the individual values of the image pixels, PLS attempts to explain the relation between image pixels and task or behavior. Data from a face encoding and recognition PET rCBF study are used to illustrate two types of PLS analysis: an activation analysis of task with images and a brain-behavior analysis. The commonalities across the two analyses are suggestive of a general face memory network differentially engaged during encoding and recognition. PLS thus serves as an important extension by extracting new information from imaging data that is not accessible through other currently used univariate and multivariate image analysis tools.

Algorithms↗

PubMed1996

Endophrenology: new statistical techniques for studies of brain form. Life on the hyphen in neuro-informatics.

The interweaving here of statistics, image analysis, and neuroscience is a fine example of how neuro-informatics is more than the concentration of its constituent disciplines. Each of the component tools of the morphometric synthesis--the deformation model, Procrustes shape coordinates, the thin-plate spline--gains greatly in power in the context of the others, and enhances, too, great recent strides in the instrumentation leading to the raw image data itself (MR scanner physics, multiple stains, new contrast agents). The modern morphometric tool kit seems better matched to the description of gross brain variation than we had any reason to expect. Now the new tools can be exploited to produce remarkably sharper new findings. At the same time, the demands of neuro-informatics will press the toolmakers to provide equivalently powerful new techniques in areas presently less developed, such as cortical form or correlations of images with parametric experimental designs or with clinical histories.

Animals↗

PubMed1996

Biometrics, biomathematics and the morphometric synthesis.

At the core of contemporary morphometrics--the quantitative study of biological shape variation--is a synthesis of two originally divergent methodological styles. One contributory tradition is the multivariate analysis of covariance matrices originally developed as biometrics and now dominant across a broad expanse of applied statistics. This approach, couched solely in the linear geometry of covariance structures, ignores biomathematical aspects of the original measurements. The other tributary emphasizes the direct visualization of changes in biological form. However, making objective the biological meaning of the features seen in those diagrams was always problematical; also, the representation of variation, as distinct from pairwise difference, proved infeasible. To combine these two variants of biomathematical modeling into a valid praxis for quantitative studies of biological shape was a goal earnestly sought though most of this century. That goal was finally achieved in the 1980s when techniques from mathematical statistics, multivariate biometrics, non-Euclidean geometry and computer graphics were combined in a coherent new system of tools for the complete regionalized quantitative analysis of landmark points together with the biomedical images in which they are seen. In this morphometric synthesis, correspondence of landmarks (biologically labeled geometric points, like "bridge of the nose") across specimens is taken as a biomathematical primitive. The shapes of configurations of landmarks are defined as equivalence classes with respect to the Euclidean similarity group and then represented as single points in David Kendall's shape space, a Riemannian manifold with Procrustes distance as metric. All conventional multivariate strategies carry over to the study of shape variation and covariation when shapes are interpreted in the tangent space to the shape manifold at an average shape. For biomathematical interpretation of such analyses, one needs a basis for the tangent space compatible with the reality of local biotheoretical processes and explanations at many different geometric scales, and one needs graphics for visualizing average shape differences and other statistical contrasts there. Both of these needs are managed by the thin-plate spline, a deformation function that has an unusually helpful linear algebra. The spline also links the biometrics of landmarks to deformation analysis of the images from which the landmarks originally arose. This article reviews the history and principal tools of this synthesis in their biomathematical and biometrical context and demonstrates their usefulness in a study of focal neuroanatomical anomalies in schizophrenia.

Anatomy↗

PubMed1996

A classification of plagiocephaly utilizing a three-dimensional computer analysis of cranial base landmarks.

Plagiocephaly is a term commonly used to describe congenital forehead asymmetry. Previous classification systems based on the various etiologies of dysmorphic crania have been used in an effort to categorize the patients into groups and to assist in treatment planning. The system most commonly used today was described by Bruneteau and Mulliken in 1992. The authors separated frontal plagiocephaly into three types: synostotic, compensational, and deformational. The present study was undertaken in order to define a simple system for classifying plagiocephaly based on Bruneteau and Mulliken's system using the patients' preoperative craniofacial computed tomography scans. The involvement of the entire coronal ring in synostotic plagiocephaly led to the choice of 20 skull base landmarks as the basis of the analysis. Nine lateral landmarks (the superior orbital fissure, the optic foramen, the zygomatic arch, the greater palatine foramen, the foramen ovale, the mastoid tip, the hypoglossal canal, the external auditory canal, and the internal auditory canal) and two midline landmarks (the crista galli and the internal occipital protuberance) were used. The changes that occurred in these landmarks were analyzed in 30 patients. The results demonstrated that Bruneteau and Mulliken's classification system underestimated the number of different subtypes of plagiocephaly. As a result, three major types of frontal plagiocephaly and several different subtypes based on the different etiologies were described. Type I plagiocephaly includes plagiocephaly resulting from cranial suture synostosis. Type II includes those with a nonsynostotic etiology. Type III describes patients with craniofacial microsomia-associated plagiocephaly. Statistical analysis was unavailable because of the small number of patients in each subtype. With a larger number of patients, we hope to refine this system for use by the surgeon in preoperative diagnosis and surgical planning. The analysis is unique in its ability to quantitate changes from normal on the x-, y-, and z-coordinates, and therefore allows for identification of both horizontal (frontal bone deviation) and vertical (ear shear) growth disturbances.

Facial Asymmetry↗

PubMed1995

Log-linear allometry of fetal craniofacial growth in Down's syndrome.

Trisomy 21 develops as a result of nondisjunction of two homologous chromosomes during either the first or second meiotic division. One of the more important consequences of these genetic alterations is the predictable, although variable disturbance in the architecture of the craniofacial region [1]. Postnatal craniofacial morphology has been extensively studied in Down's syndrome (DS). However, little information is available on human prenatal development of the head and face in such patients. The time at which changes in craniofacial phenotype first emerge in Down's syndrome fetuses and at which physical growth begins to diverge from normal is unknown. To explore these questions, we compared prenatal craniofacial growth in 50 Down's syndrome fetuses with that of 555 fetuses judged to be "typical for body weight and age" using the method of log-linear allometry [2].

Cephalometry↗

PubMed1995

Log-linear allometry of normal fetal craniofacial growth.

Normative data on human craniofacial growth during the fetal period and important to provide a broader perspective on normal morphogenesis as well as to serve as reference for analyzing craniofacial syndromes in which growth has gone awry. Over a 19-year period, the Teratology Unit at the University of Michigan Medical Center has collected data on 2,568 legally donated fetuses that have undergone necropsy examination at various gestational ages. From previous analyses, 609 of the total fetal population (25%) were designated as typical for age or body weight on the basis of normal morphology, absence of maceration, and general growth symmetry. Of the 609 fetuses reviewed, 54 were excluded secondary to incomplete data. The remaining 555 constitute the basis of this study. Seven craniofacial measurements were recorded, including head circumference (HC), brain weight, inner canthal and outer canthal distances, and distances from nasion to menton, outer canthus to tragus and auditory meatus to vertex. Statistical analysis was carried out using the single-factor allometric model of Sewall Wright. Size was estimated as the first unstandardized principal component of the logarithms of lengths and of cube roots of weights, and then allometry was expressed in the regressions of each log variable on size. Significant allometry was found as were significant differences in errors about the allometric relation, but no evidence for more than a single factor or of "nonlinearity" in the regression curves was noted. Although there were differences of specific allometric coefficients between the various measurements (i.e., the slope of the curve for IC was significantly smaller than the slope of the curve generated for HC), these specific growth rates remain in relatively strict proportion to one another from early in gestation (body weight, 54.2 gm) to later in gestation (body weight, 1,000 gm).

Cephalometry↗

PubMed1995

A three-dimensional smooth surface analysis of untreated Crouzon's syndrome in the adult.

This study compares the three-dimensional smooth surface shape of five adult patients with Crouzon's disease with nine normal skulls. A new analysis method is described which is based on smooth surface curvature. Surface samples are subdivided by a common ridge curve structure. Three-dimensional images of an average normal and an average Crouzon skull are illustrated. Comparisons between groups are performed on landmarks, as well as ridge curve and surface patch midpoints. There was as much discriminant information in the ridge curves and surface patches between landmarks as there was at the landmarks themselves. When compared with normal samples, the Crouzon's syndrome sample exhibits the following major characteristics: The midface is concave and wide, with the piriform aperture in the center more recessed than the perifery of the midface. The forehead is recessed above a frontal sinus bulge. The orbits are shallow, wide, concave, and tilted inferiorly with a mild hypertelorism. These data suggest that advancement of large, one-piece osteotomy segments will not produce a normal face, and a multisegment approach should be considered.

Adolescent↗

PubMed1994

Prenatal alcohol and offspring development: the first fourteen years.

This report summarizes findings from a prospective longitudinal study of the effects of prenatal alcohol exposure on a birth cohort of 500 offspring selected from 1,529 consecutive pregnant women in prenatal care by mid-pregnancy at two representative community hospitals. Effects of prenatal alcohol observable on size measures at birth were insignificant after 8 months. Morphometric analysis of facial features identified effects only at the very highest alcohol exposure levels. By contrast, dose-dependent effects on neurobehavioral function from birth to 14 years have been established using partial least squares (PLS) methods jointly analysing multiple measures of both alcohol dose and outcome. Particularly salient effects included problems with attention, speed of information processing, and learning problems, especially arithmetic.

Adolescent↗

PubMed1994

Generating a normalized geometric liver model using warping.

RATIONALE AND OBJECTIVES: Automated liver surface determination in abdominal computed tomography scans, currently difficult to achieve, is of interest to determine liver location and size for various medical applications, including radiation therapy treatment planning, surgical planning, and oncologic monitoring. The authors propose to facilitate automation by the addition of a priori shape information in the form of a liver model. METHODS: The normalized geometric liver model is generated by averaging outlines from a set of normal liver studies previously registered using thin-plate spline warping. The model consists of an averaged liver surface, a set of anatomic landmarks, and a deformation function. RESULTS: A liver model is presented and its ability to represent normal liver shapes is demonstrated. CONCLUSIONS: Liver surface warping provides a means of data normalization for model construction and a means of model deformation for representation of liver organ shapes.

Computer Simulation↗