PubMed Health⌕ Search

Biomedical subjects

P L Jamison

Publications and source records attributed to P L Jamison.

14 recordsLinked to original sources
PubMed2001

The subtle facial signs of prenatal exposure to alcohol: an anthropometric approach.

OBJECTIVES: The purpose was to demonstrate that an objective, multivariate case definition of fetal alcohol syndrome (FAS) and partial fetal alcohol syndrome (PFAS) can be derived by means of craniofacial anthropometry. STUDY DESIGN: Craniofacial measurements (n = 21) were taken of 100 individuals who had been exposed to alcohol before birth (41 FAS, 59 PFAS) and 31 members of a control group. Multivariate discriminant analysis was used to identify craniofacial measurements that best differentiated the 3 groups (FAS, PFAS, and control). RESULTS: Both the FAS and PFAS groups had a unique craniofacial phenotype that could be accurately discriminated from that of the control group. Stepwise discriminant analysis identified 6 craniofacial measurements that could differentiate individuals with and without prenatal alcohol exposure with 96% accuracy, 98% sensitivity, and 90% specificity. CONCLUSIONS: Individuals with FAS and PFAS have a distinctive facial phenotype that can be characterized anthropometrically. The phenotypic case definition could be used as a screening tool to identify individuals prenatally exposed to alcohol who do not exhibit a "classic" FAS phenotype but exhibit a more subtle craniofacial dysmorphia.

Adolescent↗
PubMed2000

Quantitative approach to identifying abnormal variation in the human face exemplified by a study of 278 individuals with five craniofacial syndromes.

We have two objectives in this study: to demonstrate the utility of two summary anthropometric measures for quantifying craniofacial variation and to explore some of their potential uses by physicians and clinical morphologists in general. The Craniofacial Variability Index (CVI) is a summary anthropometric measure of facial "harmony." The mean z-score, based on craniofacial anthropometry, is a measure of overall facial size. Both add an objective component to the assessment of individual facial variation and allow us to place the individual along a scale of continuous variation with predetermined limits of "normality" based on a reference or control series. Our results suggest that these summary measures coincide well with clinical assessments of abnormality in 278 individuals representing five distinct syndromes (Brachmann-de Lange, Prader-Willi, Rubinstein-Taybi, Smith-Magenis, and Sotos), each of which has an associated craniofacial component. Although craniofacial variation is continuous and the normal and syndromic populations overlap to varying degrees, the syndromic cases can be characterized in a variety of ways by using CVI as a measure of facial harmony and Mean-Z as an indicator of overall facial size. Thus, these two-objective measures offer a novel and efficient means of assessing craniofacial variation, whether they are used as tools in the clinical evaluation of subjects or as a means of exploring the nature of craniofacial variation within or between syndromes.

Adolescent↗
PubMed1998

Craniofacial variability index: a simple measure of normal and abnormal variation in the head and face.

We propose a numerical means of increasing the objectivity of describing, characterizing, and evaluating craniofacial morphology, including dysmorphology. A craniofacial variability index (CVI) can be created for an individual by obtaining a series of anthropometric measurements of the head and face, converting each measurement value to a standardized z-score, and then calculating the standard deviation for the whole set of these z-score values. This value is lowest for those faces in which all of the z-scores are in the same direction and of relatively the same magnitude and highest for faces with pronounced difference in direction and size of the individual z-scores. The CVI has a range of values with an approximately normal distribution in a reference population of 1,312 individuals. Examination of a small sample of individuals with known craniofacial syndromes indicates that the CVI in such cases consistently falls outside of the normal range of the index, and its value is highest in individuals with the greatest subjective degree of facial involvement. Finally, the CVI is robust: age, sex, size of the individual, and changes in the number of variables used in its calculation have little impact on its distribution. When used in conjunction with traditional clinical assessment, the CVI has a number of potential clinical applications including initial diagnostic screening, demonstrating age-related changes in postnatal development of patients with facial syndromes, and pre- and post-surgical assessments of individuals with craniofacial anomalies.

Anthropometry↗
PubMed1994

Cephalometric evidence for a dominantly inherited predisposition to cleft lip-cleft palate in a single large kindred.

Several studies have demonstrated an association between facial shape in parents and the presence of oral clefts in their offspring. However, these observations have been of little practical value because it has been assumed that facial shape was just one predisposing component among many in a multifactorial model of inheritance. Cephalometric analysis of a large family with 5 generations of affected individuals suggests that facial shape can be used to identify presumed carriers of a major gene associated with an increased risk for oral clefts. Discriminant function analysis indicates that such at risk individuals can be recognized effectively through a combination of increased midfacial and nasal cavity widths, reduced facial height, and a flat facial profile. The ability to identify minimally affected gene carriers within families would provide critical information needed in the search for molecular markers that segregate with the genetic risk for clefting.

Cephalometry↗
PubMed1994

Effect of prenatal testosterone administration on palmar dermatoglyphic intercore ridge counts of rhesus monkeys (Macaca mulatta).

Dermatoglyphic ridge counts of the prints of 59 rhesus monkeys (Macaca mulatta) whose mothers had been treated with injections of testosterone during their pregnancies were studied to determine the effect of the day the hormone began to be administered, the amount of hormone administered, and the number of days of hormone administration upon the dermatoglyphic variation of the offspring. Of the three hormone variables, only the day of beginning administration (STARTDAY) was significantly associated with dermatoglyphic variation, and its positive significance was demonstrated with the ridge counts of Area I on both the left and right hand, Area II of the left hand, and the total ridge counts of both hands. These results are discussed within the context of the timing of the dermatoglyphic window, and the differences in the findings between the monkey and earlier human studies are addressed.

Animals↗
PubMed1993

Brief communication: measurement size, precision, and reliability in craniofacial anthropometry: bigger is better.

In this paper we examine the results of an intraobserver measurement error study involving 49 craniofacial variables that ranged in size from less than 1 cm to approximately 20 cm. Repeat measurements were taken on 10 male and 10 female adult subjects (19-59 years old). Our focus is on the relationship between measurement size and measurement error across the 49 variables. We found that the size of the variable showed no relationship with the magnitude of the error as measured by the technical error of measurement. When the error was expressed as a coefficient of relative variation (Malina et al.: Vital and Health Statistics, Series 11, No. 23. Washington, DC: US Department of Health and Human Services, 1973), this quantity was negatively associated with the size of the measurement. Conversely, reliability (Fleiss: The Design and Analysis of Experiments. New York: John Wiley & Sons, 1986) was positively correlated with measurement size. We did not find effects of scale (Marks et al.: Am. J. Epidemiol. 130:578-587, 1989) within the individual measurements. Thus, for the range of size of the craniofacial measurements in this study, measurement size must be added to the list of factors such as ease of locating landmarks, measurement technique, and systematic bias in the application of the technique that can affect precision and reliability in anthropometry.

Adult↗
PubMed1990

Dermatoglyphic and anthropometric relationships within the Iñupiat (Eskimo) hand.

On the basis of earlier findings with Easter Islanders suggesting a positive correlation between dermatoglyphic variables and hand anthropometric measurements, the present study was designed to determine if such a relationship could be generalized to another population, namely, Iñupiat (Eskimo). Since some dermatoglyphic and anthropometric variables were available for both sides of the body, the extension of this study to explore the question of asymmetry was also possible. The Iñupiat sample numbered 142 male and 176 female adult inhabitants of five Alaskan North Slope communities. The major findings of this study included, for males, significant negative correlations between left arm length and digital ridge counts and positive relationships between the palmar variable of axial index and hand length on both hands. For females, the hand breadth/length index was negatively related to most of the digital variables. Very little definitive information regarding the relationship of the asymmetry variables between the two types of measures was ascertained.

Adult↗
PubMed1990

Secular trends and the pattern of growth in arctic populations.

Examinations of growth patterns in Arctic populations suggest that Inuit/Inupiat (Eskimo) children display a unique pattern relative to European or continental U.S. children. This pattern--high weight for height--becomes established early in life and it has existed for as long as researchers have Inuit or Inupiat data. This paper will examine the growth pattern relative to the NCHS reference standard, using recent data from the Arctic and several indices combining height and weight. Of particular concern will be the persistence of this pattern in the face of secular trends in growth that have occurred over the past 50 years. Trends for height increase have been greater than those for weight but weight for height still remains well above the 50th percentile of the U.S. reference for these Arctic groups.

Anthropometry↗
PubMed1989

Meaning of biodistance statistics: a test case using adult monozygotic twins.

Anthropometry, historically one of the primary research techniques in physical anthropology, has been widely utilized in biodistance studies. The complex genetic and environmental interaction that governs the expression of anthropometric dimensions, together with concerns over measurement error, have sometimes clouded the interpretation of biodistances based upon anthropometry. In this study, 51 pairs of adult monozygotic twins were analysed using discriminant analysis and Mahalanobis' generalized distance. Both male and female twins, grouped by first- versus second-born, displayed very small, statistically insignificant distances between groups. When literature estimates of intra-observer measurement errors were used as a frame of reference, the average absolute differences between the twin pairs were approximately twice the size of the measurement error estimates. The results of this study suggest that, first, the environmental effect upon the genetically influenced traits measured by anthropometry is not large enough to bring about significant multivariate differences between identical twin pairs; and, second, biodistance studies based upon anthropometry can be reliable so long as measurement error is minimized.

Adult↗
PubMedDate not supplied

Assortative mating in monozygotic twins.

This study investigated assortative mating in a series of monozygotic twins in terms of anthropometric variables. Initially the twins were analyzed independent of each other, and the results showed fairly clear homogamy among female MZ twins and their spouses, after correcting for age. Further, when stature was partialled out, several anthropometric measures remained significantly correlated. The results for male MZ twins and their spouses were not nearly so clear-cut. A second analysis treated the co-twins together, and once again, the female MZ sets tended to show assortative mate choice for stature while the male MZ twins/spouses were not significantly correlated. A follow-up analysis investigated whether husbands of the female twins were correlated to each other, and negative results were found for all of the 46 anthropometric variables. An apparent contradiction was resolved in the case of stature by regressing spouse stature against that of the co-twins. It was found that although each of the twins was assortatively mating, one member of the twin set consistently married a taller husband, but the difference was not constant. This had the effect of producing divergent regression lines.

Anthropometry↗
PubMedDate not supplied

Measurement precision and reliability in craniofacial anthropometry: implications and suggestions for clinical applications.

Craniofacial anthropometry has become an important tool used by both clinical geneticists and reconstructive surgeons. Yet little attention has been paid to the potentially serious problem of measurement error. This paper examines intra-observer measurement error and precision (also called repeatability or reliability) for 52 commonly used anthropometric variables of the head and face. Two factors proved critical to reliability: magnitude of the measurement in question and the degree to which its constituant landmarks could be readily identified. Thus, all of the measurement variables with means above 10 cm proved to have good or excellent reliability. In contrast measurement variables with means below 10 cm were more likely to have poor reliability. This trend was especially evident in variables with means of 6 cm or less where 18 of the 20 variables in this range had poor reliability. The least reliable variables were those like philtrum breadth, columella breadth, and nasal root breadth that combine small magnitude with difficult to define landmarks. While these results suggest that it may be prudent to avoid using craniofacial variables with small dimensions this may be neither practical nor desirable. In such cases repeat measurements may be the best means for optimizing reliability.

Adult↗