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PubMed2005

Traditional Chinese medicine based subgrouping of irritable bowel syndrome patients.

Partly from lack of effective conventional therapeutics, patients with irritable bowel syndrome (IBS) turn to complementary and alternative approaches, including Traditional Chinese Medicine (TCM). Key to TCM's approach to IBS is individualized therapies targeted at subgroups. Subgroups represent distinct patterns of dysregulation (e.g. "excess" or "deficiency") identified by both intestinal and extra-intestinal symptoms. Our objective was to identify operational criteria supporting the existence of TCM-based subgroups in IBS and to assess reliability and validity of these criteria. Using TCM principles, items were selected on face validity from conventional questionnaires. TCM practitioners evaluated items for content and face validity. Symptom items and a set of patient cases with item responses were validated by examining patient's pattern of response to items and assessing the consistency with which practitioners diagnosed patients on the spectrum of an "excess" or "deficiency" syndrome. Standard correlation analysis revealed 33 intestinal and extra-intestinal symptom items. There was high degree of practitioner agreement in assessing individual items to particular patterns. External validation by practitioners of cases showed high internal consistency among practitioners (Cronbach's alpha coefficients of 0.91 and 0.87 for excess and deficiency, respectively) and high correlation of average practitioner rating to original questionnaire generated scores (Pearson correlation coefficients of 0.94 and 0.92 for excess and deficiency, respectively). This pilot study provides preliminary support for a methodology to identify novel subgroups of IBS patients related to the TCM classification, which may differ in underlying pathophysiology and treatment responses.

Case-Control Studies↗
PubMed2001

Are empirically supported treatments valid for ethnic minorities? Toward an alternative approach for treatment research.

The psychological community has given considerable attention to the problem of establishing empirically supported treatments (ESTs). The authors argue that a scientific practice that discriminates against some approaches to knowledge undermines the EST's relevance for communities of color. They examine the EST project's contribution to knowledge of effective treatments for ethnic minorities by considering both how knowledge is constructed and the limits of research (e.g., external validity). Alternatives on how to best contribute to treatment research of clinical utility with diverse populations are articulated. An approach for treatment research, derived from an integration of the hypothesis-testing and discovery-oriented research approaches, is presented, and recommendations to advance treatment research with ethnic minority communities are offered.

Cultural Characteristics↗
PubMed1994

Subtypes of psychosocial adjustment to breast cancer.

By means of cluster analytic techniques, four subtypes of psychosocial adjustment were identified in a sample of 122 breast cancer patients who completed the Psychosocial Adjustment to Illness Scale. Internal consistency and internal validity of the derived typology were suggested by the finding that two different hierarchical agglomerative clustering methods (average linkage between groups, Ward's) produced similar solutions. Three of the derived subtypes reported normal affect levels but different patterns of relative strengths and dysfunctions, while the fourth subtype appeared to be highly distressed and globally maladjusted. External validation was demonstrated by differentiating the subtypes on variables of negative affect, avoidance coping, and fighting spirit. The clinical and heuristic implications of these findings are discussed. The findings highlight the need for comprehensive assessment of psychosocial functioning of cancer patients. They demonstrate that even non-emotionally distressed patients can have very different profiles of adjustment and may benefit from correspondingly individually tailored psychosocial interventions.

Adaptation, Psychological↗
PubMed2003

[The Comprehensive Cohort Design as alternative to the randomized controlled trial in rehabilitation research: advantages, disadvantages, and implementation in the SARAH study].

In rehabilitation research new therapies have to be evaluated within randomized trials as the best choice for proving the efficacy. Randomized controlled trials are widely accepted as the definitive method for evaluating the efficacy of new therapies. The random assignment of patients to their treatment ensures the internal validity of the comparison of new treatments with controls. Often patients in a randomized trial only represent a small proportion of the patients who satisfy the inclusion criteria of the trial. This will especially be true in rehabilitation medicine because of strong preferences of the patients for one or the other therapy. An assessment of the external validity of trial results can best be achieved by comparing the study population to the population of patients who met the eligibility criteria but did not consent to randomization. The Comprehensive Cohort Design (CCD) is designed to have the opportunity of recruiting all patients fulfilling these eligibility criteria regardless of their consent to randomisation. Advantages and disadvantages of this study design will be discussed in detail and on the example of the SARAH-study.

Adult↗
PubMedDate not supplied

[The measurement of the depersonalisation-derealisation-syndrome with the German version of the Cambridge Depersonalisation Scale (CDS)].

Self-rating scales have proved to be essential in the study of depersonalisation, which regrettably, is still seldom recognised in clinical practice. In recent studies the Cambridge Depersonalisation Scale (CDS) has emerged as an useful instrument for the study of depersonalisation. Here we report a validation study of the authorised German version of the CDS in a sample of 91 inpatients, 43 of whom had pathological depersonalisation and 48 without pathological depersonalisation. The SCID-D Interview for depersonalisation and derealisation was used as the gold standard and the German version of the Dissociative Experiences Scale was used to test the external validity of the scale. The German version of the CDS was found to have high internal consistency and reliability (alpha = 0,95 and Guttman Split-half = 0,95) and could differentiate patients with pathological depersonalisation from the control group. We therefore conclude that the German version of the CDS can be considered as reliable and valid.

Depersonalization↗
PubMed1999

Decisional balance for immoderate drinking in college students.

Immoderate drinking in college is common and is associated with significant negative sequelae. In this study, measures of Decisional Balance for Immoderate Drinking were developed. This construct is proposed to represent the basic decision-making process that is used by students when deciding whether to drink at immoderate levels or not. Furthermore this construct is embedded in a larger model of behavior change, the Transtheoretical Model of Change, which has been shown to be effective in understanding many health-related behaviors across a wide variety of populations. A total of 629 college students were administered a 25-item decisional balance questionnaire in 1993-1994. Exploratory and confirmatory analyses suggested two different solutions, a two-factor solution and a three-factor solution, but did not provide clear evidence for the psychometric superiority of one over the other. The three-factor solution was chosen as it was seen as an elaboration of the two-factor solution, and validity evidence for this solution is presented. The three factors were labeled the Pros, the Cons-Actual, and the Cons-Potential of Immoderate Drinking. The Cons-Actual scale is a measure of negative affective states associated with current drinking whereas the Cons Potential measures the risk of more concrete negative effects of drinking. External validity was established by the significant and meaningful differences on a number of alcohol-related variables including consumption variables, three measures of negative sequelae of immoderate drinking, and Stage of Change, the organizing construct of the Transtheoretical Model of Change.

Adolescent↗
PubMed2002

Appropriate time frames for data collection in quality of life research among cancer patients at the end of life.

Longitudinal research has been recommended as the most appropriate research design to ensure the validity of quality of life assessments. However, high attrition and non-random missing data in quality of life studies for terminal cancer patients raise questions about generalizability of the study, and at worst they may jeopardize interpretation of the results. Appropriate time frames for eliciting information directly from terminal cancer patients can ensure the internal and external validity of quality of life research in end-of-life care, allow health care professionals to detect sensitively the effects of end-of-life care within the shortest intervention period, and make comparisons across studies possible. From a review of the literature, it is recommended that the appropriate time frame for interviewing terminal cancer patients about their quality of life be a weekly assessment schedule based on the following factors: (a) the median survival of terminal cancer patients enrolling in a hospice/palliative care program is approximately 30 days and there are substantial number of patients who die in each week; (b) at the final weeks of life, quality of life and symptoms of some terminal cancer patients change dramatically; and (c) the shortest intervention period that is likely to give a clinically significant effect of end-of-life care management is 1 week after the enrollment in end-of-life care.

Humans↗
PubMedDate not supplied

The diagnostic value of scoring models for organic and non-organic gastrointestinal disease, including the irritable-bowel syndrome.

Scoring models based on history and physical examination have been developed to discriminate patients with non-organic gastrointestinal disease from those who have organic disease. The application of these models may lead to more efficient diagnosis and prevent somatization. Although the models have high diagnostic accuracy in the population in which they have been developed, their value in other populations has not been established. In this study previously developed models were tested in validation populations defined by the original selection criteria from the studies in which the models were developed and in unselected general practice and outpatient populations. The diagnostic performance of the models are expressed in terms of odds ratio and sensitivity and specificity for the classification of patients as having organic and non-organic disease. The diagnostic performance of all the models were rather low in the validation populations. Relatively few elements of the models had independent diagnostic value. In addition, the correlation between the scoring models, expressed in Cohen's kappa, was extremely low. The diagnostic values of the scoring models were not reproduced in comparable and unselected populations. Therefore, it is concluded that the diagnostic value of such a model has little external validity.

Adolescent↗
PubMed2005

Screening test accuracy studies: how valid are our conclusions? Application to visual inspection methods for cervical screening.

While the basic concepts associated with screening are simple, studying the value of new tests requires a very strict methodology. This paper summarizes lessons learned regarding appropriate methodologies to assess the value of new screening approaches using visual inspection with acetic acid (VIA), a screening test for cervical pre-cancerous lesions, as an example. In addition to being convenient to, safe for and acceptable by target community members, a screening test should be reliable and have good test characteristics (i.e. be able to discriminate well between early disease and non disease). Test reliability assesses the degree to which repeated measurements of the test yields the same result. To ensure reproducibility of study findings, test reliability should be assessed before any evaluation of test accuracy. The accuracy of a test (specificity and sensitivity) is measured using cross-sectional studies with adequate sample size. Several basic features are necessary to ensure internal validity for such studies: (a) final disease status data should be obtained for all subjects, (b) all tests results must be determined independently of previous results, (c) the reference standard used to determine the disease status should be accurate, (d) the full "spectrum" of the disease should be included in the study. The study results should also have external validity to be applicable to other populations to which the test will be applied. All these consideration are exemplified by 17 very heterogeneous studies published to date assessing VIA test accuracy. The assessment of a new screening test is the first step in researching a new cancer prevention strategy. For this reason, this step should be carefully addressed through rigorous studies.

Acetic Acid↗
PubMed2002

How will we know a lapse when we see one? Comment on Leri and Stewart (2002).

The article by F. Leri and J. Stewart (2002) addresses the validity of animal models of relapse in a more sophisticated manner than does much prior research. These researchers have shown that drug self-administration can be influenced by the presence of drug contingent cues as well as by active self-administration versus passive infusion of "lapse" doses. This research also leads to additional questions about the external validity of animal relapse models. Current relapse models may lack validity because of the parameters of drug exposure, because abstinence is imposed on the organism, and because there is no motivational influence that counters resumption of drug self-administration. F. Leri and J. Stewart's (2002) article encourages a more thorough assessment of the motivational context of relapse models.

Animals↗
PubMedDate not supplied

Cluster subtypes within stage of change in a representative sample of smokers.

In this paper a three-level conceptualization of approaches to matching self-help behavior change strategies to individuals is presented based on the Transtheoretical Model of Change. Two of the model's intervention approaches, tailoring to Stage-of-Change and creating completely individualized interventions, have already been developed and implemented in previous research. A third intervention approach, in between stage-tailored and individualized, is targeting subtype groups within each Stage of Change. The subtype targeted intervention approach is in the initial development stage of empirically determining and validating the stage subtypes. Three studies are presented which investigate stage subtypes within a representative sample of 4,144 smokers in the Precontemplation, Contemplation, and Preparation Stages of Change. Within each Stage-of-Change study, two cluster analyses were performed using the Pros, Cons, and Situational Temptations from the Transtheoretical Model to establish cluster replicability. Cluster solutions were externally validated using the 10 Processes of Change and 2 smoking behavior variables. Four distinct subtypes were found in Precontemplation and Contemplation, and five subtypes were found in Preparation. These subtypes closely replicate subtypes previously found in a convenience sample of smokers and provide strong evidence for the existence of subtypes within the first three Stages of Change.

Adaptation, Psychological↗
PubMed2004

A risk index for prostate cancer.

BACKGROUND: The aim of the present study was to create a simple numerical index predicting the presence of prostate cancer in a group of high risk patients, for the purpose of selecting those most likely to need prostate biopsy. METHODS: 100 consecutive patients at high risk of having prostate cancer seen at Ramathibodi Hospital, Thailand between November 2000 and February 2002 were prospectively studied. All patients underwent transrectal prostate biopsies. The following predictor variables were obtained: age, digital rectal examination (DRE) findings, prostate specific antigen level, transrectal ultrasonography (TRUS) findings, and prostate volume determined by TRUS. The outcome was the presence of prostate cancer on histological examination of the biopsy specimens. A risk index for prostate cancer based on the linear predictor of a multiple logistic regression model was created. RESULTS: Almost all predictor variables were significantly related to the presence of prostate cancer. The final multiple logistic regression model with four categorized predictors (excluding DRE) was shown to have good discrimination, calibration, and cross-validity. For a cutoff risk index of 10, corresponding to a 10% probability of having prostate cancer, the sensitivity for detecting prostate cancer was 96.2%, with a specificity of 73.0%. Based on this cutoff, 55% of patients in this series might not require prostate biopsy. CONCLUSION: A risk index for prostate cancer was developed. If this index can be externally validated, the potential savings from avoiding unnecessary prostate biopsies, on the basis of selection using the index, could be significant.

Age Factors↗
PubMed2001

Prevalence, incidence, signs and treatment of clinical listeriosis in dairy cattle in England.

The prevalence, incidence and clinical signs of listeriosis in dairy cattle in England were investigated by means of a postal questionnaire survey of 1500 dairy farmers. The response rate was 64.1 per cent. Overall the farm prevalence of listeriosis was 11.7 per cent, 9.3 per cent for milking cows, 5.0 per cent for replacement heifers and 1.4 per cent for dairy calves. The within-herd incidence rate per thousand animal-years was 51.4 for all cases, 39.7 for milking cows, 86.6 for replacement heifers and 73.7 for dairy calves. Most cases of clinical listeriosis were reported between December and May, and the most common signs were silage eye, followed by nervous signs. The results of the questionnaire were validated internally by re-estimating the farm prevalence by including only those cases diagnosed by a veterinarian or veterinary investigation centre; the prevalence did not change significantly. The proportion of cases which were culled or died of encephalitic listeriosis was compared with the proportion diagnosed during statutory BSE reporting. The fact that the two proportions were similar provided external validation for the results of the questionnaire.

Animals↗
PubMed2002

The subtypes of major depression in a twin registry.

OBJECTIVE: The subtypes of major depression (MD) remain incompletely understood. While there is consensus about the existence of MD with 'typical' vegetative features, further data are required to evaluate the existence of MD with atypical features. METHOD: Assessment of MD symptomatology in year prior to interview was available in 6846 individual twins from a population-based twin registry. The nine 'A' criteria for DSM-IV MD were unpacked so that the nature of sleep disturbance, appetite and weight changes, and motoric alterations were recorded. Latent class analysis was used to create an empirical typology of MD. RESULTS: Seven latent classes appeared to provide the best representation of the data. The most severe of these classes had interpretable profiles corresponding to typical MD, atypical MD, and 'minor' but seemingly important depressive states. These classes were generally more deviant than a comparison group for nearly all available validators. There tended to be a gradient with the typical class being most extreme, minor depressive classes the least extreme, and the atypical class having an intermediate position. CONCLUSIONS: Our findings support the existence of atypical depression as a phenomenological subtype of MD. Besides the differences in symptom patterns, there are many more similarities than differences across a range of external validators. Similar to other reports, we found evidence of the importance and morbidity of depressive symptomatology that does not meet the DSM-IV MD thresholds.

Adult↗
PubMed2002

Using individualism and collectivism to compare cultures--a critique of the validity and measurement of the constructs: comment on Oyserman et al. (2002).

Analyzing national and ethnic differences in individualism and collectivism, D. Oyserman, H. M. Coon, and M. Kemmelmeier (2002) showed that small differences in scales or samples produce markedly divergent results, challenging the validity of these constructs. The author examines the following limitations of research on individualism and collectivism: It treats nations as cultures and culture as a continuous quantitative variable; conflates all kinds of social relations and distinct types of autonomy; ignores contextual specificity in norms and values; measures culture as the personal preferences and behavior reports of individuals; rarely establishes the external validity of the measures used; assumes cultural invariance in the meaning of self-reports and anchoring and interpretation of scales; and reduces culture to explicit, abstract verbal knowledge.

Cognition↗
PubMed2006

Prediction of MLH1 and MSH2 mutations in Lynch syndrome.

CONTEXT: Lynch syndrome is caused primarily by mutations in the mismatch repair genes MLH1 and MSH2. OBJECTIVES: To analyze MLH1/MSH2 mutation prevalence in a large cohort of patients undergoing genetic testing and to develop a clinical model to predict the likelihood of finding a mutation in at-risk patients. DESIGN, SETTING, AND PARTICIPANTS: Personal and family history were obtained for 1914 unrelated probands who submitted blood samples starting in the year 2000 for full gene sequencing of MLH1/MSH2. Genetic analysis was performed using a combination of sequence analysis and Southern blotting. A multivariable model was developed using logistic regression in an initial cohort of 898 individuals and subsequently prospectively validated in 1016 patients. The complex model that we have named PREMM(1,2) (Prediction of Mutations in MLH1 and MSH2) was developed into a Web-based tool that incorporates personal and family history of cancer and adenomas. MAIN OUTCOME MEASURE: Deleterious mutations in MLH1/MSH2 genes. RESULTS: Overall, 14.5% of the probands (130/898) carried a pathogenic mutation (MLH1, 6.5%; MSH2, 8.0%) in the development cohort and 15.3% (155/1016) in the validation cohort, with 42 (27%) of the latter being large rearrangements. Strong predictors of mutations included proband characteristics (presence of colorectal cancer, especially > or =2 separate diagnoses, or endometrial cancer) and family history (especially the number of first-degree relatives with colorectal or endometrial cancer). Age at diagnosis was particularly important for colorectal cancer. The multivariable model discriminated well at external validation, with an area under the receiver operating characteristic curve of 0.80 (95% confidence interval, 0.76-0.84). CONCLUSIONS: Personal and family history characteristics can accurately predict the outcome of genetic testing in a large population at risk of Lynch syndrome. The PREMM(1,2) model provides clinicians with an objective, easy-to-use tool to estimate the likelihood of finding mutations in the MLH1/MSH2 genes and may guide the strategy for molecular evaluation.

Adaptor Proteins, Signal Transducing↗
PubMed2003

Selection of data sets for QSARs: analyses of Tetrahymena toxicity from aromatic compounds.

The aim of this investigation was to develop a strategy for the formulation of a valid ecotoxicological-based QSAR while, at the same time, minimizing the required number of toxicological data points. Two chemical selection approaches-distance-based optimality and K Nearest Neighbor (KNN), were used to examine the impact of the number of compounds used in the training and testing phases of QSAR development (i.e. diversity and representivity, respectively) on the predictivity (i.e. external validation) of the QSAR. Regression-based QSARs for the ectotoxic potency for population growth impairment of aromatic compounds (benzenes) to the aquatic ciliate Tetrahymena pyriformis were developed based on descriptors for chemical hydrophobicity and electrophilicity. A ratio of one compound in the training set to three in the test set was applied. The results indicate that from a known chemical universe, in this case 385 derivatives, robust QSARs of equal quality may be developed from a small number of diverse compounds, validated by a representative test set. As a conservative recommendation it is suggested that there should be a minimum of 10 observations for each variable in a QSAR.

Animals↗
PubMed2001

Assessing culture via the Internet: methods and techniques for psychological research.

This study examines the acculturation experiences of Arabic immigrants and assesses the utility of the Internet as a data collection tool. Based on in-depth pilot interview data from 10 male Arabic immigrants and items selected from pre-existing measures, the Male Arabic Ethnic Identity Measure (MAEIM) was developed. Male Arab immigrants (115 males) were solicited through traditional methods in addition to the Internet. Satisfactory reliability and validity were reported for the MAEIM. No significant differences emerged between the Internet and Midwestern samples. The Internet proved to be an effective method for soliciting a relatively large, geographically dispersed sample of Arabic immigrants. The use of the Internet as a research tool is examined in the context of anonymity, networking, low-cost, perceived interactive control, methodological rigor, and external validity. The Internet was an effective vehicle for addressing concerns raised by prospective participants. It is suggested that the Internet may be an important method to assess culture-relevant variables in further research on Arab and other immigrant populations.

Acculturation↗