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PubMed1991

Validity and generalizability of global ratings in an objective structured clinical examination.

The performance of foreign medical graduates on multistation standardized patient-based tests and used to determine the validity and generalizability of global ratings of their clinical competence made by expert examiners. Data were derived from the entrance examinations of the 1989 and 1990 applicants to the Ontario Pre-Internship Program and the exit examination of 24 participants from the 1989 cohort. For each candidate, the examiners completed a detailed checklist and two five-point global ratings dealing with the candidate's approach to the patients' problem and attitude toward the patient. Generalizability coefficients for both ratings were satisfactory and stable across cohorts. Construct validity of the global ratings was demonstrated by comparing entry and exit ratings and by evidence of significant and positive correlations between the global ratings and total test scores. Tentative evidence of criterion validity of the global ratings was demonstrated. These findings suggest that global ratings by expert examiners can be used as an effective form of assessment in multistation standardized patient examinations.

Attitude of Health Personnel↗
PubMed1995

Body image, body dysphoria, and dietary restraint: factor structure in nonclinical subjects.

The principal aim of this study was to examine the factor structure of several assessment methods used to measure dietary restraint, body dissatisfaction, and body image. Factor analysis was employed to identify and confirm the primary constructs measured by these assessment methods. A total of 206 undergraduate women were recruited as subjects. This sample was divided into two subsets of 100 and 106 subjects. On the first subset, principle components analysis identified three factors: body dysphoria, dietary restraint, and body image. With the second subset of subjects, confirmatory factor analysis cross-validated this factor structure. A two factor solution, body dysphoria and dietary restraint, was identified and confirmed when the body image measure was converted to a self-minus-ideal discrepancy score. These findings are discussed in relation to the definition of control groups to be used in studies of anorexia and bulimia nervosa. Guidelines for the selection of measures for each of the three factors also are presented.

Adult↗
PubMed2001

Environmental features are important in determining protein secondary structure.

We have investigated amino acid features that determine secondary structure: (1) the solvent accessibility of each side chain, and (2) the interaction of each side chain with others one to four residues apart. Solvent accessibility is a simple model that distinguishes residue environment. The pairwise interactions represent a simple model of local side chain to side chain interactions. To test the importance of these features we developed an algorithm to separate alpha-helices, beta-strands, and "other" structure. Single residue and pairwise probabilities were determined for 25,141 samples from proteins with <30% homology. Combining the features of solvent accessibility with pairwise probabilities allows us to distinguish the three structures after cross validation at the 82.0% level. We gain 1.4% to 2.0% accuracy by optimizing the propensities, demonstrating that probabilities do not necessarily reflect propensities. Optimization of residue exposures, weights of all probabilities, and propensities increased accuracy to 84.0%.

Algorithms↗
PubMed2003

The Aging Males' Symptoms (AMS) scale: review of its methodological characteristics.

BACKGROUND: The current paper reviews data from different sources to get a closer impression on the psychometric and other methodological characteristics of the Aging Males' Symptoms (AMS) scale gathered recently. The scale was designed and standardized as self-administered scale to (a) to assess symptoms of aging (independent from those which are disease-related) between groups of males under different conditions, (b) to evaluate the severity of symptoms over time, and (c) to measure changes pre- and post androgen replacement therapy. The scale is in widespread use (14 languages). METHOD: Original data from different studies in many countries were centrally analysed to evaluate reliability and validity of the AMS. RESULTS: Reliability measures (consistency and test-retest stability) were found to be good across countries, although the sample size was sometimes small. VALIDITY: The internal structure of the AMS in healthy and androgen deficient males, and across countries was sufficiently similar to conclude that the scale really measures the same phenomenon. The sub-scores and total score correlations were high (0.8-0.9) but lower among the sub-scales (0.5-0.7). This however suggests that the subscales are not fully independent. The comparison with other scales for aging males or screening instruments for androgen deficiency showed sufficiently good correlations, illustrating a good criterion-oriented validity. The same is true for the comparison with the generic quality-of-life scale SF36 where also high correlation coefficients have been shown. Methodological analyses of a treatment study of symptomatic males with testosterone demonstrated the ability of the AMS scale to measure treatment effect, irrespective of the severity of complaints before therapy. It was also shown that the AMS result can predict the independently generated (physician's) opinion about the individual treatment effect. CONCLUSION: The currently available methodological evidence points towards a high quality of the AMS scale to measure and to compare HRQoL of aging males over time or before/after treatment, it suggests a high reliability and high validity as far as the process of construct validation could be pressed ahead yet. But certainly more data will become available, particularly from ongoing clinical studies.

Adult↗
PubMed2001

A clinical validation of the Dysmorphic Concern Questionnaire.

OBJECTIVE: The current study addressed the concept of dysmorphic concern as a symptom that may exist in a number of disorders. The aims of the study were to: (i) validate a recently developed questionnaire that measures dysmorphic concern, the Dysmorphic Concern Questionnaire (DCQ); and (ii) evaluate the relationship of dysmorphic concern to depressed mood, social phobia, and obsessive-compulsive symptomatology. METHOD: Sixty-five psychiatric inpatients were diagnosed using the computerized version of the Composite International Diagnostic Interview (CIDI-A). They then completed the DCQ, and questionnaires measuring body dysmorphic disorder (the Body Dysmorphic Disorder Examination, or BDDE), depression, social phobia, and obsessive-compulsive disorder (OCD). The factor structure and convergent validity of the DCQ were determined, and associations with mood and anxiety symptoms explored. RESULTS: The DCQ was found to be a reliable and valid instrument that is sensitive to dysmorphic concern. Furthermore, although dysmorphic concern was associated with body dysmorphic disorder (BDD), depression, social phobia and OCD, only the score from the BDDE predicted DCQ score in a multiple regression analysis. Finally, BDD symptomatology was best defined by the presence of negative body beliefs as measured by the DCQ. CONCLUSIONS: Negative body beliefs are the hallmark of BDD. However, the existence of dysmorphic concern does not necessarily imply a diagnosis of BDD. The DCQ is a quick and efficient means of identifying dysmorphic concern in those who present with depression, OCD, social phobia or BDD.

Adolescent↗
PubMed2005

Aging Males' Symptoms scale: a standardized instrument for the practice.

The Aging Males' Symptoms (AMS) scale was designed and standardized as self-administered scale (a) to assess symptoms of aging (independent from those which are disease-related) among groups of males under different conditions, (b) to evaluate the severity of symptoms over time, and (c) to measure changes pre- and post-androgen replacement therapy. It is a short and easy to apply instrument, it has a very simple evaluation scheme, and was internationally well accepted (translated into over 20 languages). Methodological test characteristics are: a) reliability measures: (internal consistency and test-retest stability) were found to be good across countries, b) validity: the internal structure of the AMS in healthy and androgen deficient males and across countries was sufficiently similar to conclude that the scale really measures the same phenomenon across all age groups. The comparison of the AMS with the two established screening instruments for androgen deficiency showed sufficiently good compatibility. Consequently, a screening tool for hypogonadism was developed, consisting of the AMS scale, body mass index (BMI) and age. The test characteristics of this screening tool (sensitivity and specificity) are promising. Clinicians often consider validity as utility for outcome measurement. The AMS scale showed a convincing ability to measure treatment effects on quality of life across the full range of severity of complaints before therapy. The distribution of complaints of testosterone deficient men before therapy almost returned to normal values after 12 weeks of testosterone treatment.

Adult↗
PubMed2006

Development and validation of the Infertility Self-Efficacy scale.

OBJECTIVE: To develop and validate a scale of perceived self-efficacy for people coping with infertility treatment. DESIGN: Self-efficacy scale development involved: [1] item generation with medical experts in reproductive health; [2] a principal components analysis with varimax rotation to identify underlying item components; [3] test-retest reliability and construct (convergent and discriminant) validity with infertility patients, who were administered the Infertility Self-Efficacy (ISE) scale with other measures; and [4] expert acceptability, as determined by reproductive health professionals. SETTING: Recruitment at a fertility center, a national infertility organization, and medical trials web pages. PATIENT(S): A total of 213 participants (159 women; 54 men) with a diagnosis of infertility in the past 2 years were recruited for the various study phases. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): Participants' infertility self-efficacy was assessed with an online assessment battery using the ISE scale; comparison mental health measures assessed current levels of fertility problem distress, perceived stress, and coping style. Reliability, validity, and component structure of the ISE was assessed. RESULT(S): Measurement development yielded a brief 16-item ISE scale that taps an infertility patient's perception about his or her ability to engage in a set of cognitive, emotional, and behavioral skills related to the medical treatment of infertility. The single component of "cognitive/affect regulation" suggests this core set of skills is relevant to successfully managing the experience of infertility. The ISE correlations with comparison mental health measures were as expected, suggesting good convergent and discriminant validity. CONCLUSION(S): The ISE scale appears to be a reliable and valid measure of an individual's self confidence in areas related to health promotion during infertility treatment. Assessing an infertility patients' self-efficacy with the ISE may be useful in clinical research and as a counseling tool to help guide patients in actively managing their fertility treatment.

Adaptation, Psychological↗
PubMed1997

An objective structured clinical examination for evaluating psychiatric clinical clerks.

PURPOSE: To assess the feasibility, reliability, and validity of an objective structured clinical examination (OSCE) for psychiatric clinical clerks. METHOD: In 1995 two parallel forms of a ten-station OSCE (eight clinical stations, two writing stations) were developed at the University of Toronto Faculty of Medicine Each 12-minute performance-based clinical station was assessed by a faculty psychiatrist using both a checklist for each student's performance content and a global-rating scale of the performance process. The students' clinical-station scores were calculated as the average of their content and process scores (expressed as percentages). Examiners also recorded an overall judgment of each students' performance (pass, borderline, or fail) and wrote [in collaboration with the standardized patient (SP) at that station] comments on each student's performance. There were two criteria for a passing grade: a total mark of 60% or higher across all ten stations and a "pass" or "borderline" mark in at least five of the eight clinical stations. Each OSCE form was administered three times. RESULTS: The first form was used to examine 94 clerks, the second form to examine 98 clerks. The students' mean scores for the two forms were 70.47% (SD, 6.33%) and 67.66% (SD, 7.05%), respectively. In addition to the standard evaluation information collected on the students, several critical incidents occurred (e.g., a student's loss of control of emotions) that may identify potential problems in professional conduct. The direct cost for one administration of the examination was approximately Can$3,300: the largest portion of this was for the SPs' time spent in training and performing their roles. CONCLUSION: Preliminary evidence suggests that a psychiatry OSCE is feasible for assessing complex psychiatric skills. However, careful attention must be paid to SP training, examination monitoring, detection of critical incidents, and provision of feedback to students, faculty, and SPs. The university's previous system of oral examinations required approximately 600 faculty hours per year. The OSCE requires approximately 450 faculty hours, and the 150 hours saved almost cover the Can$20,000 that the examination costs each year. In all, the OSCE is an evaluation system that has demonstrable reliability and is more enjoyable for both the faculty and the students.

Clinical Clerkship↗
PubMed1986

Concurrent and predictive validity of a self-reported measure of medication adherence.

Adherence to the medical regimen continues to rank as a major clinical problem in the management of patients with essential hypertension, as in other conditions treated with drugs and life-style modification. This article reviews the psychometric properties and tests the concurrent and predictive validity of a structured four-item self-reported adherence measure (alpha reliability = 0.61), which can be easily integrated into the medical visit. Items in the scale address barriers to medication-taking and permit the health care provider to reinforce positive adherence behaviors. Data on patient adherence to the medical regimen were collected at the end of a formalized 18-month educational program. Blood pressure measurements were recorded throughout a 3-year follow-up period. Results showed the scale to demonstrate both concurrent and predictive validity with regard to blood pressure control at 2 years and 5 years, respectively. Seventy-five percent of the patients who scored high on the four-item scale at year 2 had their blood pressure under adequate control at year 5, compared with 47% under control at year 5 for those patients scoring low (P less than 0.01).

Humans↗
PubMed1998

A unified statistical framework for sequence comparison and structure comparison.

We present an approach for assessing the significance of sequence and structure comparisons by using nearly identical statistical formalisms for both sequence and structure. Doing so involves an all-vs.-all comparison of protein domains [taken here from the Structural Classification of Proteins (scop) database] and then fitting a simple distribution function to the observed scores. By using this distribution, we can attach a statistical significance to each comparison score in the form of a P value, the probability that a better score would occur by chance. As expected, we find that the scores for sequence matching follow an extreme-value distribution. The agreement, moreover, between the P values that we derive from this distribution and those reported by standard programs (e.g., BLAST and FASTA validates our approach. Structure comparison scores also follow an extreme-value distribution when the statistics are expressed in terms of a structural alignment score (essentially the sum of reciprocated distances between aligned atoms minus gap penalties). We find that the traditional metric of structural similarity, the rms deviation in atom positions after fitting aligned atoms, follows a different distribution of scores and does not perform as well as the structural alignment score. Comparison of the sequence and structure statistics for pairs of proteins known to be related distantly shows that structural comparison is able to detect approximately twice as many distant relationships as sequence comparison at the same error rate. The comparison also indicates that there are very few pairs with significant similarity in terms of sequence but not structure whereas many pairs have significant similarity in terms of structure but not sequence.

Animals↗
PubMed2002

Validity of a self-administered questionnaire for assessing physical work loads in a general population.

The aim of the study was to evaluate eight questions concerning physical loads, used in public health questionnaires. Working women and men (203) completed a self-administered questionnaire twice, following a test-retest method. The questions were also validated with a structured interview. Response agreement was calculated with Cohen's kappa statistics with quadratic weights (kappa w). Test-retest agreement varied from 0.74 to 0.92, and inter-method agreement from 0.38 to 0.81. The lowest coefficients were for the questions concerning bent/twisted work postures (kappa w 0.38) and repetitive movements (kappa w 0.39). The results did not indicate any substantial influence of gender, type of work or musculoskeletal complaint. The questions concerning general physical activity and sitting work postures, and physical exercise/sports during leisure times, had good validity. The questions concerning bent/twisted work posture and repetitive movements need to be re-designed.

Adult↗
PubMedDate not supplied

A four-dimensional probabilistic atlas of the human brain.

The authors describe the development of a four-dimensional atlas and reference system that includes both macroscopic and microscopic information on structure and function of the human brain in persons between the ages of 18 and 90 years. Given the presumed large but previously unquantified degree of structural and functional variance among normal persons in the human population, the basis for this atlas and reference system is probabilistic. Through the efforts of the International Consortium for Brain Mapping (ICBM), 7,000 subjects will be included in the initial phase of database and atlas development. For each subject, detailed demographic, clinical, behavioral, and imaging information is being collected. In addition, 5,800 subjects will contribute DNA for the purpose of determining genotype- phenotype-behavioral correlations. The process of developing the strategies, algorithms, data collection methods, validation approaches, database structures, and distribution of results is described in this report. Examples of applications of the approach are described for the normal brain in both adults and children as well as in patients with schizophrenia. This project should provide new insights into the relationship between microscopic and macroscopic structure and function in the human brain and should have important implications in basic neuroscience, clinical diagnostics, and cerebral disorders.

Adolescent↗
PubMed2006

Reliability and validity of the BASIS-24 Mental Health Survey for Whites, African-Americans, and Latinos.

Increasing racial and ethnic diversity calls for mental health assessment instruments that are appropriate, reliable, and valid for the wide range of cultures that comprise the current US population. However, most assessment instruments have not been tested on diverse samples. This study assessed psychometric properties and sensitivity to change of the revised Behavior and Symptom Identification Scale (BASIS-24) among the three largest race/ethnicity groups in the USA: Whites, African-Americans, and Latinos. BASIS-24 assessments were obtained for 2436 inpatients and 2975 outpatients treated at one of 27 mental health and/or substance abuse programs. Confirmatory factor analysis and several psychometric tests supported the factor structure, reliability, concurrent validity, and sensitivity of the instrument within each race/ethnicity group, although discriminant validity may be weaker for African-Americans and Latinos than for Whites. Further research is needed to test and validate assessment instruments with other race/ethnicity groups.

Adolescent↗
PubMed2002

Treatment outcome in individuals with chronic pain: is the Pain Stages of Change Questionnaire (PSOCQ) a useful tool?

The efficacy of psychological treatments emphasising a self-management approach to chronic pain has been demonstrated by substantial empirical research. Nevertheless, high drop-out and relapse rates and low or unsuccessful engagement in self-management pain rehabilitation programs have prompted the suggestion that people vary in their readiness to adopt a self-management approach to their pain. The Pain Stages of Change Questionnaire (PSOCQ) was developed to assess a patient's readiness to adopt a self-management approach to their chronic pain. Preliminary evidence has supported the PSOCQ's psychometric properties. The current study was designed to further examine the psychometric properties of the PSOCQ, including its reliability, factorial structure and predictive validity. A total of 107 patients with an average age of 36.2 years (SD=10.63) attending a multi-disciplinary pain management program completed the PSOCQ, the Pain Self-Efficacy Questionnaire (PSEQ) and the West Haven-Yale Multidimensional Pain Inventory (WHYMPI) pre-admission and at discharge from the program. Initial data analysis found inadequate internal consistencies of the precontemplation and action scales of the PSOCQ and a high correlation (r=0.66, P<0.01) between the action and maintenance scales. Principal component analysis supported a two-factor structure: 'Contemplation' and 'Engagement'. Subsequent analyses revealed that the PSEQ was a better predictor of treatment outcome than the PSOCQ scales. Discussion centres upon the utility of the PSOCQ in a clinical pain setting in light of the above findings, and a need for further research.

Activities of Daily Living↗
PubMed2002

Latent structure of eating disorder symptoms: a factor analytic and taxometric investigation.

OBJECTIVE: The latent structure of eating disorder symptoms, as defined by DSM-IV, was tested in a group of 341 women with and without an eating disorder diagnosis. METHOD: The study group consisted of 201 participants with a diagnosis of anorexia nervosa, bulimia nervosa, binge eating disorder, or eating disorder not otherwise specified; 24 comparison subjects who were obese but did not have an eating disorder diagnosis; and 116 normal-weight comparison subjects. The presence and severity of DSM-IV eating disorder symptoms was assessed with the semi-structured Interview for the Diagnosis of Eating Disorders-IV. The study group was randomly divided into two subgroups for factor analytic studies, and the data were subjected to exploratory and confirmatory factor analysis. Pilot taxometric analyses were used to examine whether the obtained factors represented true dimensions or latent discrete classes. RESULTS: In exploratory factor analyses with data from subgroup 1, three factors were found to account for 66% of the variance in eating disorder symptoms: binge eating, fear of fatness/compensatory behaviors, and drive for extreme thinness. Confirmatory factor analysis cross-validated this factor structure with data from subgroup 2. The eating disorder groups and comparison groups were found to differ on at least one of the three factors. The results of the taxometric analyses were inconsistent with a strictly dimensional model of eating disorders and suggested that some features may be dimensional whereas others may be taxonic (discrete). DISCUSSION: The eating disorders, as defined by DSM-IV, can be conceptualized as having three latent features. Taxometric tests found empirical support for conceptualizing bulimia nervosa and binge eating disorder as discrete syndromes.

Adult↗
PubMed2001

Interaction of new PNA-based molecules with TAR RNA of HIV-1: molecular modelling and biological evaluation.

During the HIV-1 replication process, interactions between the RNA sequence, named TAR RNA, and the viral protein, Tat, permit a fast and efficient transcription of viral DNA into RNA. Based on the NMR structure of TAR RNA from the PDB, two Peptidic Nucleic Analog- (PNA) based molecules were designed by molecular modelling, the first one targeting G32 U31 and the second targeting U31 C30 free loop bases. Before designing the molecules, the flexibility of the TAR RNA was evaluated by molecular dynamics (MD). The molecules studied are composed of three domains: an arginine, a linker, and two PNA bases. First, molecules were designed and the linker length was optimized to fit the TAR RNA; second, a MD simulation on the TAR RNA molecule complex was performed to validate the molecular structure. Optimal molecules were synthesized and tested on infected cells. The experimental results support the choices made in the design of the molecules.

Circular Dichroism↗
PubMedDate not supplied

EMDep: a web-based system for the deposition and validation of high-resolution electron microscopy macromolecular structural information.

This paper describes the design and implementation of a Web-based deposition system, EMDep, for macro-molecular volumes determined by electron microscopy and deposited at the European Bioinformatics Institute (EBI) for inclusion in the Electron Microscopy Data Base (EMDB). EMDep is a flexible and portable system (http://www.ebi.ac.uk/msd-srv/emdep/) that allows for the acceptance and validation of data, by an interactive depositor-driven operation. The system takes full advantage of the knowledge and expertise of the experimenters, rather than relying on the database curators, for the complete and accurate description of the structural experiment and its results.

Algorithms↗
PubMed1996

X-ray structure of yeast inorganic pyrophosphatase complexed with manganese and phosphate.

The three-dimensional structure of the manganese-phosphate complex of inorganic pyrophosphatase from Saccharomyces cerevisiae has been refined to an R factor of 19.0% at 2.4-A resolution. X-ray data were collected from a single crystal using an imaging plate scanner and synchrotron radiation. There is one dimeric molecule in the asymmetric unit. The upper estimate of the root-mean-square coordinate error is 0.4 A using either the delta A plot or the superposition of the two crystallographically independent subunits. The good agreement between the coordinates of the two subunits, which were not subjected to non-crystallographic symmetry restraints, provides independent validation of the structure analysis. The active site in each subunit contains four manganese ions and two phosphates. The manganese ions are coordinated by the side chains of aspartate and glutamate residues. The phosphate groups, which were identified on the basis of their local stereochemistry, interact either directly or via water molecules with manganese ions and lysine, arginine, and tyrosine side chains. The phosphates are bridged by two of the manganese ions. The outer phosphate is exposed to solvent. The inner phosphate is surrounded by all four manganese ions. The ion-binding sites are related to the order of binding previously established from kinetic studies. A hypothesis for the transition state of the catalytic reaction is put forward.

Crystallography, X-Ray↗