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Results for “Structural validation”

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PubMed1995

Measuring the functional status of patients with low back pain. Assessment of the quality of four disease-specific questionnaires.

STUDY DESIGN: This study was a literature review of the quality of four disease-specific functional status questionnaires for patients with low back pain: Oswestry; Million; Roland; and Waddell disability questionnaire. OBJECTIVES: The questionnaires were evaluated in terms of general description, scale structure, reliability, validity, responsiveness, and clinical research applications. SUMMARY OF BACKGROUND DATA: Functional status is an outcome of great interest for clinical trials of low back pain. METHODS: A computer-aided search was conducted of articles published between 1981 and 1993 and references given in selected relevant publications. Articles were selected if at least one of the four functional status questionnaires was used or if the authors gave relevant information about the methodology of these questionnaires. RESULTS: There was not enough information available about the criteria of item selection used for the development of the questionnaires. The test-retest reproducibility of the questionnaires seemed satisfactory. The Oswestry and Roland disability questionnaires have been used and evaluated more frequently than the Million and Waddell. Therefore, we can be more certain about the validity and responsiveness of the former pair of questionnaires. CONCLUSION: In the absence of a gold standard, direct comparisons of evaluative functional status questionnaires in a single patient group are needed. Through direct comparisons, comparative validity and responsiveness can be assessed. Functional status measures are not currently used in many settings in which they would be valuable. It is important to encourage their wider use in clinical trials. Additional research is needed to compare and improve the existing questionnaires.

Activities of Daily Living↗
PubMed2001

Neural systems underlying episodic memory: insights from animal research.

Two strategies used to uncover neural systems for episodic-like memory in animals are discussed: (i) an attribute of episodic memory (what? when? where?) is examined in order to reveal the neuronal interactions supporting that component of memory; and (ii) the connections of a structure thought to be central to episodic memory in humans are studied at a level of detail not feasible in humans. By focusing on spatial memory (where?) and the hippocampus, it has proved possible to bring the strategies together. A review of lesion, disconnection and immediate early-gene studies in animals reveals the importance of interactions between the hippocampus and specific nuclei in the diencephalon (most notably the anterior thalamic nuclei) for spatial memory. Other parts of this extended hippocampal system include the mammillary bodies and the posterior cingulate (retrosplenial) cortex. Furthermore, by combining lesion and immediate early-gene studies it is possible to show how the loss of one component structure or tract can influence the remaining regions in this group of structures. The validity of this convergent approach is supported by new findings showing that the same set of regions is implicated in anterograde amnesia in humans.

Amnesia↗
PubMed2000

Nonparametric rank-based methods for group sequential monitoring of paired censored survival data.

This research gives methods for nonparametric sequential monitoring of paired censored survival data in the two-sample problem using paired weighted log-rank statistics with adjustments for dependence in survival and censoring outcomes. The joint asymptotic closed-form distribution of these sequentially monitored statistics has a dependent increments structure. Simulations validating operating characteristics of the proposed methods highlight power and size consequences of ignoring even mildly correlated data. A motivating example is presented via the Early Treatment Diabetic Retinopathy Study.

Biometry↗
PubMed1995

The prevention of mechanical birth trauma by means of computer aided simulation of delivery by means of nuclear magnetic resonance imaging and finite element analysis.

Anatomic disproportion gains an increasing interest in obstetrics. Imaging procedures (radiologic pelvimetry, computed or magnetic resonance imaging (MRI) fail to reflect the dynamics of delivery including deformations of the birth channel as well as of fetal structures. To validate findings of imaging procedures in this respect a method has been developed to perform a dynamic, biomechanical postprocessing of the static informations obtained from MRI. Using an especially developed software MRI pixel matrices of maternal pelvis and fetal head were color-codef1p4d--according to the principle of same density--line data were created. After sectional attribution of the resulting polygones a three-dimensional mesh of so called Finite elements (FE) was created, which then can be used for deformation analysis. Fetal head was then moved through the birth channel by means of computed simulation. This allows not only ongoing deformations to be visualized but also resulting forces to be calculated for at any time of the delivery process for any point of the anatomical model. Performing these simulations assuming various anatomic and physiologic conditions an obstetrical-biomechanical data basis could be obtained, that was implemented in a PC-based expert system. This allows interpretation of pelvimetric data with regard to birth dynamics.

Biomechanical Phenomena↗
PubMed1982

The rapid disability rating scale-2.

A revised version of the Rapid Disability Rating Scale (RDRS-2) is presented. Item definitions have been sharpened and directions expanded to indicate that ratings are based upon the patient's performance in regard to behavior, and that prosthesis normally used by the patient should be included in the assessment. Three items have been added to increase the breadth of the scale. Response items have been changed from three-point to four-point ratings in order to increase group discrimination amd make the scale more sensitive to changes in treatment. The new appraisals of reliability, factor structure, and validity are reported, along with the potential uses of the scale.

Activities of Daily Living↗
PubMed1996

Alcian blue. Now you see it, now you don't.

A brief outline of the history and chemistry of the copper pthalocyanin-based Alcian blue dyes highlights the adverse effects of commercial secrecy and entrepreneurial dishonesty on the use of these valuable histochemical and biochemical reagents in the biological sciences. The acquisition of detailed and validated chemical structures required the avoidable expenditure of much time that otherwise would have been spent on new research. The combination of this chemical knowledge with experiments on isolated polyanions, using critical electrolyte concentration (CEC) techniques, established a molecular recognition paradigm of Alcian blue usage in histochemistry. New reagents (Cuprolinic and Cupromeronic blues) were synthesised to investigate and support the hypothesis that Alcian blue did not intercalate with DNA. They were made with the important additional aim of using them in electron microscopy of polynucleotides (in the case of Cuprolinic blue) and non-nucleotide polyanions, such as sulphated proteoglycans in extracellular matrices (in the case of Cupromeronic blue). The cationic groups of Alcian blue are easily removed in very mild conditions, producing insoluble blue pigment in situ (ingrain dying). This reaction underlies its unique capability to stain in repeated cycles, thus greatly amplifying sensitivity of detection of substrates present in very small amounts in tissues and on electrophoretic strips etc.

Alcian Blue↗
PubMed2001

Radiographic progression in rheumatoid arthritis: does it reflect outcome? Does it reflect treatment?

Although there is clear face validity that structural damage is related to outcome, it is difficult to prove this. Recently, more evidence became available that structural damage, as assessed on plain films, is indeed related to disease activity in clinical trials and therefore can be used to assess the effect of treatment. Also, a relationship between structural damage and outcome, mainly defined as physical disability, was established. Several examples of findings in recent publications are presented which lead to the following conclusions. There is a relation between the response to treatment measured as clinical disease activity and measured as radiographic progression in most clinical therapeutic trials. A strong relation between local inflammation and progression of damage in the individual joint is present. This is robust evidence for the hypothesis that inflammation leads to structural damage. There is a good relation between the damage in small and large joints as assessed on plain films. Damage measured in small joints is a good substitute for overall damage. Disease activity is always strongly correlated with functional disability throughout the disease course. There is an increasing relation between disability and structural damage with increasing disease duration.

Arthritis, Rheumatoid↗
PubMed2000

Emotional and cognitive consequences of head injury in relation to the glasgow outcome scale.

OBJECTIVE: There is current debate over the issue of the best way of assessing outcome after head injury. One criticism of scales of disability and handicap such as the Glasgow outcome scale (GOS) is that they fail to capture the subjective perspective of the person with head injury. The aims of the study were to investigate aspects of the validity of structured interviews for the GOS, and address the issue of the relation between the GOS and subjective reports of health outcome. METHODS: A total of 135 patients with head injury were assessed using the GOS and an extended GOS (GOSE) and other measures of outcome and clinical status at 6 months after injury. RESULTS: There were robust correlations between the GOS and measures of initial injury severity (particularly post-traumatic amnesia) and outcome assessed by disability scales (particularly the disbility rating scale (DRS)); however, associations with cognitive tests were generally modest. There were also strong correlations with self report measures of health outcome: both the GOS and GOSE were related to depression measured by the Beck depression inventory, mental wellbeing assessed by the general health questionnaire, and to all subscales of the short form-36. The GOS scales were also strongly associated with frequency of reported symptoms and problems on the neurobehavioural functioning inventory. CONCLUSIONS: The GOS and GOSE show consistent relations with other outcome measures including subjective reports of health outcome; they thus remain useful overall summary assessments of outcome of head injury.

Adolescent↗
PubMed2000

Familial aggregation of psychotic symptoms in Huntington's disease.

OBJECTIVE: The mutation responsible for Huntington's disease is an elongated and unstable trinucleotide (CAG) repeat on the short arm of chromosome 4. Psychotic symptoms are more common in patients with Huntington's disease than in the general population. This study explored the relationship of psychosis in Huntington's disease patients with the number of CAG repeats and family history of psychosis. METHOD: Forty-four patients with Huntington's disease, 22 with and 22 without psychotic symptoms, were recruited from two university-affiliated medical genetics clinics in Seattle and Vancouver, B.C. Psychiatric assessments of the subjects were made through chart review, and diagnoses were validated by structured interviews in a subset of patients. The demographic and clinical characteristics of the psychotic and nonpsychotic patients were compared. RESULTS: The two groups did not differ in demographic and clinical characteristics, except that subjects with psychosis were significantly more likely than nonpsychotic subjects to have a first-degree relative with psychosis. In eight of nine families in which Huntington's disease probands with psychosis had a first-degree relative with psychosis, the relative's psychosis co-occurred with Huntington's disease. In the Huntington's disease probands with psychosis, the onset of psychosis correlated with the onset of the neurological symptoms of Huntington's disease, and the age at onset of psychosis was lower in probands with a higher number of CAG repeats. CONCLUSIONS: Patients with Huntington's disease and psychotic symptoms may have a familial predisposition to develop psychosis. This finding suggests that other genetic factors may influence susceptibility to a particular phenotype precipitated by CAG expansion in the Huntington's disease gene.

Adolescent↗
PubMed1991

Assessment and diagnosis of borderline personality disorder.

Borderline personality disorder is common in treatment settings and may be so in the general population. In this guide to assessment strategies for diagnosing borderline personality disorder, the authors discuss the reliability and validity of structured interviews and self-report instruments and suggest the use of a self-report questionnaire as a cost-effective screening test. Assessment problems, such as the need for longitudinal observation, are reviewed. Essential features of the recommended diagnostic approach include clarity about the diagnostic concept, consideration of the full range of diagnostic criteria, incorporation of recently developed diagnostic methodologies, care in distinguishing personality disorders from comorbid axis I syndromes, and complete assessment of the full range of axis II disorders.

Borderline Personality Disorder↗
PubMed2000

Production of diagnostic rules from a neurotologic database with decision trees.

A decision tree is an artificial intelligence program that is adaptive and is closely related to a neural network, but can handle missing or nondecisive data in decision-making. Data on patients with Meniere's disease, vestibular schwannoma, traumatic vertigo, sudden deafness, benign paroxysmal positional vertigo, and vestibular neuritis were retrieved from the database of the otoneurologic expert system ONE for the development and testing of the accuracy of decision trees in the diagnostic workup. Decision trees were constructed separately for each disease. The accuracies of the best decision trees were 94%, 95%, 99%, 99%, 100%, and 100% for the respective diseases. The most important questions concerned the presence of vertigo, hearing loss, and tinnitus; duration of vertigo; frequency of vertigo attacks; severity of rotational vertigo; onset and type of hearing loss; and occurrence of head injury in relation to the timing of onset of vertigo. Meniere's disease was the most difficult to classify correctly. The validity and structure of the decision trees are easily comprehended and can be used outside the expert system.

Databases, Factual↗
PubMed1999

Discovering diagnostic rules from a neurotologic database with genetic algorithms.

Data on patients with Meniere's disease, vestibular schwannoma, traumatic vertigo, sudden deafness, benign paroxysmal positional vertigo, or vestibular neuritis were retrieved from the database of otoneurologic expert system ONE for the development and testing of a genetic algorithm (GA). The accuracy of the diagnostic rules in solving the test cases was 81%, 91%, 92%, 95%, 96%, and 98% for the respective diseases. The best rules retrieved from the GA were described by a set of questions with the most likely answers. The most important questions concerned the duration of hearing loss and the occurrence of head injury. The validity and structure of the rules created with a GA can be analyzed in detail. For rare diseases, some other reasoning process can be used, for example, case-based reasoning.

Algorithms↗
PubMed1999

The Rorschach Inkblot Test: a case of overstatement?

In the 1940s, inflated claims were often made regarding the Rorschach Inkblot Test. Over half a century later, overstatements regarding the test are still common. The present article identifies problems with the Rorschach regarding norms, cultural sensitivity, interrater reliability, test-retest reliability, validity, factor structure, and accessibility of supporting studies. Contrary to overstated claims made on behalf of the Rorschach, the test continues to be a highly problematic instrument from a psychometric standpoint.

Adult↗
PubMed1993

The product of the Drosophila segment polarity gene armadillo is part of a multi-protein complex resembling the vertebrate adherens junction.

Sequence similarity between the Drosophila segment polarity protein Armadillo and the vertebrate adherens junction protein beta-catenin raised the possibility that adherens junctions function in transduction of intercellular signals like that mediated by Wingless/Wnt-1. To substantiate the sequence similarity, properties of Armadillo were evaluated for consistency with a junctional role. Armadillo is part of a membrane-associated complex. This complex includes Armadillo, a glycoprotein similar in size to vertebrate cadherins, and the Drosophila homolog of alpha-catenin. Armadillo co-localizes with junctions that resemble vertebrate adherens junctions in morphology and position. These results suggest that Drosophila and vertebrate adherens junctions are structurally similar, validating use of Armadillo and its associated proteins as a model for vertebrate adherens junctions.

Animals↗
PubMed1987

Analysis of individual, intraspecific and interspecific variability in quantitative parameters of caprine tooth enamel structure.

Qualitative and quantitative features of mammalian tooth enamel structure are increasingly being used in taxonomic and phylogenetic analyses, although the variability shown by these traits has not received adequate consideration. This study evaluates the variability displayed by nine quantitative parameters in deep, intermediate, and superficial molar enamel in the closely related bovids Ovis aries and Capra hircus. These parameters are assessed in terms of the absolute and/or relative variability evinced at a given depth within a single individual, among conspecific individuals, and between species samples. The degrees of relative variability expressed at a given depth are comparable among conspecific individuals and between taxonomic samples. Nevertheless, in many instances, there are significant differences in absolute variability amongst individuals. Also, in four parameters for which individual specimen averages could be calculated, the equality of these means among conspecifics can be rejected. Variability is not equivalent at different enamel depths. The null hypothesis of equality of individual, conspecific variances can be rejected most commonly for parameters measured in deep and superficial enamel, and coefficients of variation also tend to be higher for deep and superficial enamel than for enamel of intermediate depth. The greater variability displayed by deep and especially superficial enamel may be related to the initial onset and the terminal phase of ameloblastic secretory activity. Taxonomic and phylogenetic analyses that utilize quantitative data on enamel structure are valid only if comparisons have been made at equivalent enamel depths.

Ameloblasts↗
PubMed2000

Psychiatric epidemiology: selected recent advances and future directions.

Reviewed in this article are selected recent advances and future challenges for psychiatric epidemiology. Major advances in descriptive psychiatric epidemiology in recent years include the development of reliable and valid fully structured diagnostic interviews, the implementation of parallel cross-national surveys of the prevalences and correlates of mental disorders, and the initiation of research in clinical epidemiology. Remaining challenges include the refinement of diagnostic categories and criteria, recognition and evaluation of systematic underreporting bias in surveys of mental disorders, creation and use of accurate assessment tools for studying disorders of children, adolescents, the elderly, and people in less developed countries, and setting up systems to carry out small area estimations for needs assessment and programme planning. Advances in analytical and experimental epidemiology have been more modest. A major challenge is for psychiatric epidemiologists to increase the relevance of their analytical research to their colleagues in preventative psychiatry as well as to social policy analysts. Another challenge is to develop interventions aimed at increasing the proportion of people with mental disorders who receive treatment. Despite encouraging advances, much work still needs to be conducted before psychiatric epidemiology can realize its potential to improve the mental health of populations.

Epidemiology↗
PubMed2001

[Specific aspects of rhinomanometry in children with nasal septum deformity in the region of absorbing part of the nasal valve].

Available are original data on rhinomanometry in children with nasal septum distortion in the anterior part. Nasal patency before and after anemisation of the mucosa was measured in health and disease. Pressure in collapse of the nasal valve in children is higher than in adults, while dynamic range of the valve action in growing flow of the inspired air is more noticeable. In distortion of the nasal septum at the level of the absorbing part of the nasal valve anemisation reduces the air flow while the dynamic range is not detected. It is discussed whether early surgical intervention in children under sparing approach to nasal structures is valid.

Child↗