239 resultados para Statistical performance indexes


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Background: Sensitivity and specificity of anti-human tissue transglutaminase antibodies (anti-htTGA) seem to be superior to those of anti-tissue transglutaminase of guinea pig (anti-gptTGA) for screening patients with celiac disease (CD), but there are still controversies. The aim of this study was to evaluate the performance of two INOVA ELISA kits to detect IgA anti-htTGA and anti-gptTGA in patients with and without CD. Methods: The study groups were comprised of 49 anti-endomysial antibody (EMA)-positive untreated-CD, and 123 controls (EMA-negative treated CD, EMA-negative chronic diarrhea, autoimmune hepatitis, inflammatory bowel disease and healthy people). Results: The agreement between the two ELISAs was statistically significant in all study groups and there was no significant difference between them (92.7% agreement; kappa=0.70; kappa p=0.001; McNemar p=1). All patients with serum reactivity of more than 100 units had histologic diagnosis of CD. In seven of 10 patients with treated-CD who had control biopsies, villous atrophy was still present in four who tested positive by both kits. Two of three celiacs with histologic remission tested positive for both anti-tTGA. Conclusions: the anti-gptTGA and anti-htTGA determination were equally efficient in identifying patients with untreated-CD with high titers of EMA. Whatever the anti-tTGA ELISA used, the reactivity above 100 units was always related to active CD diagnosed by histologic alterations in intestinal biopsies. The anti-tTGA reactivity by both kits was not only similar in determining histologic activity in the follow-up of CD after a gluten free diet, but also in identifying positive sera from the control groups, regardless if CD has been confirmed by duodenal biopsies. (Clin. Lab. 2010;56:29-35)

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Objective. The purpose of this study was to estimate the Down syndrome detection and false-positive rates for second-trimester sonographic prenasal thickness (PT) measurement alone and in combination with other markers. Methods. Multivariate log Gaussian modeling was performed using numerical integration. Parameters for the PT distribution, in multiples of the normal gestation-specific median (MoM), were derived from 105 Down syndrome and 1385 unaffected pregnancies scanned at 14 to 27 weeks. The data included a new series of 25 cases and 535 controls combined with 4 previously published series. The means were estimated by the median and the SDs by the 10th to 90th range divided by 2.563. Parameters for other markers were obtained from the literature. Results. A log Gaussian model fitted the distribution of PT values well in Down syndrome and unaffected pregnancies. The distribution parameters were as follows: Down syndrome, mean, 1.334 MoM; log(10) SD, 0.0772; unaffected pregnancies, 0.995 and 0.0752, respectively. The model-predicted detection rates for 1%, 3%, and 5% false-positive rates for PT alone were 35%, 51%, and 60%, respectively. The addition of PT to a 4 serum marker protocol increased detection by 14% to 18% compared with serum alone. The simultaneous sonographic measurement of PT and nasal bone length increased detection by 19% to 26%, and with a third sonographic marker, nuchal skin fold, performance was comparable with first-trimester protocols. Conclusions. Second-trimester screening with sonographic PT and serum markers is predicted to have a high detection rate, and further sonographic markers could perform comparably with first-trimester screening protocols.

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Objective: The objective of this study was to identify variables that could predict the quality of gait in patients with transtrochanteric femoral fractures after treatment. Materials and Methods: Hospitalized patients diagnosed with transtrochanteric femoral fractures were selected between September/2005 and August/2006 and followed-up for 6 months after the trauma date. An observational prospective study was conducted to assess the quality of gait 3 and 6 months after fracture in 31 patients (13 males and 18 females). The mean age was 76 +/- 2,7. Results: Seven patients (22,6%) passed away during the follow-up period. The patients with associated fractures or with four or more co-morbidities showed a worse quality of gait after 6 months. Patients without orthopaedic complications or who got partial weight load prior to 30 days showed a better performance. Conclusion: The quantification of predictive gait indexes allows us to propose new treatment approaches consistently to the different realities showed by each group of patients.

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Objective: The aim of this article is to propose an integrated framework for extracting and describing patterns of disorders from medical images using a combination of linear discriminant analysis and active contour models. Methods: A multivariate statistical methodology was first used to identify the most discriminating hyperplane separating two groups of images (from healthy controls and patients with schizophrenia) contained in the input data. After this, the present work makes explicit the differences found by the multivariate statistical method by subtracting the discriminant models of controls and patients, weighted by the pooled variance between the two groups. A variational level-set technique was used to segment clusters of these differences. We obtain a label of each anatomical change using the Talairach atlas. Results: In this work all the data was analysed simultaneously rather than assuming a priori regions of interest. As a consequence of this, by using active contour models, we were able to obtain regions of interest that were emergent from the data. The results were evaluated using, as gold standard, well-known facts about the neuroanatomical changes related to schizophrenia. Most of the items in the gold standard was covered in our result set. Conclusions: We argue that such investigation provides a suitable framework for characterising the high complexity of magnetic resonance images in schizophrenia as the results obtained indicate a high sensitivity rate with respect to the gold standard. (C) 2010 Elsevier B.V. All rights reserved.

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The Direct Assessment of Functional Status-Revised (DAFS-R) is an instrument developed to objectively measure functional capacities required for independent living. The objective of this study was to translate and culturally adapt the DAFS-R for Brazilian Portuguese (DAFS-BR) and to evaluate its reliability and validity. The DAFS-BR was administered to 89 older patients classified previously as normal controls, mild cognitive impairment (MCI) and Alzheimer`s disease (AD). The results indicated good internal consistency (Cronbach`s alpha = 0.78) in the total sample. The DAFS-BR showed high interobserver reliability (0.996; p < .001) as well as test-retest stability over 1-week interval (0.995; p < .001). Correlation between the DAFS-BR total score and the Informant Questionnaire on Cognitive Decline in the Elderly (IQCODE) was moderate and significant (r = -.65, p < .001) in the total sample, whereas it did not reach statistical significance within each diagnostic group. Receiver operating characteristic curve analyses suggested that DAFS-BR has good sensitivity and specificity to identify MCI and AD. Results suggest that DAFS-BR can document degrees of severity of functional impairment among Brazilian older adults.

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Background: Neuropsychological deficits have been reported in association with first-episode psychosis (FEP). Reductions in grey matter (GM) volumes have been documented in FEP subjects compared to healthy controls. However, the possible inter-relationship between the findings of those two lines of research has been scarcely investigated. Objective: To investigate the relationship between neuropsychological deficits and GM volume abnormalities in a population-based sample of FEP patients compared to healthy controls from the same geographical area. Methods: FEP patients (n = 88) and control subjects (n = 86) were evaluated by neuropsychological assessment (Controlled Oral Word Association Test, forward and backward digit span tests) and magnetic resonance imaging using voxel-based morphometry. Results: Single-group analyses showed that prefrontal and temporo-parietal GM volumes correlated significantly (p < 0.05, corrected) with cognitive performance in FEP patients. A similar pattern of direct correlations between neocortical GM volumes and cognitive impairment was seen in the schizophrenia subgroup (n = 48). In the control group, cognitive performance was directly correlated with GM volume in the right dorsal anterior cingulate cortex and inversely correlated with parahippocampal gyral volumes bilaterally. Interaction analyses with ""group status"" as a predictor variable showed significantly greater positive correlation within the left inferior prefrontal cortex (BA46) in the FEP group relative to controls, and significantly greater negative correlation within the left parahippocampal gyrus in the control group relative to FEP patients. Conclusion: Our results indicate that cognitive deficits are directly related to brain volume abnormalities in frontal and temporo-parietal cortices in FEP subjects, most specifically in inferior portions of the dorsolateral prefrontal cortex. (C) 2009 Elsevier B.V. All rights reserved.

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Background: Androgenic anabolic steroids (AAS) are synthetic hormone derivatives of testosterone and are mainly used to enhance athletic performance and muscle mass, but medical applications also have been described. Short- and long-term side effects have been demonstrated in many organs, but the liver adverse effects are the most common and serious ones associated with AAS use. However, these effects have been supported by few clinical and experimental studies. Objective: To evaluate the hepatic function and structure after 5 wk of nandrolone decanoate administration at three different doses. Methods: Twenty-seven adult male Wistar rats were randomly assigned to the following groups: control, clinical, intermediate, and suprapharmacological doses of nandrolone decanoate during 5 wk. Results: The biochemical studies showed that nandrolone decanoate administration leads to a dose-dependent increase in serum levels of the aspartate aminotransferase (AST) (P < 0.05), alanine aminotransferase (ALT) (P < 0.01), and alkaline phosphatase (ALP) (P < 0.001), as well as a significant decrease in total proteins (P < 0.01), bilirubin (P < 0.05), total cholesterol and fractions (P < 0.05), and triglycerides (P < 0.05). Although a significant statistical difference was found for AST, ALT, and ALP when compared with the control group, their values remained within the normal range. The number of Kupffer cells was increased in the liver parenchyma (P < 0.05), and the content of collagen was increased in the central lobular vein wall, in the hepatic parenchyma, and in the portal space (P < 0.05). Conclusions: These results suggest that subchronic treatment with nandrolone decanoate, mainly administered at higher-than-clinical doses, are potentially deleterious to the liver, leading to incipient fibrosis.

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Objective: To compare the volume of the hippocampus and parahippocampal gyrus in elderly individuals with and without depressive disorders, and to determine whether the volumes of these regions correlate with scores on memory tests. Method: Clinical and demographic differences, as well as differences in regional gray matter volumes, were assessed in 48 elderly patients with depressive disorders and 31 control subjects. Brain (structural MRI) scans were processed using statistical parametric mapping and voxel-based morphometry. Cognitive tests were administered to subjects in both groups. Results: There were no between-group gray matter volume differences in the hippocampus or parahippocampal gyrus. In the elderly depressed group only, the volume of the left parahippocampal gyrus correlated with scores on the delayed naming portion of the visual verbal learning test. There were also significant direct correlations in depressed subjects between the volumes of the left hippocampus, right and left parahippocampal gyrus and immediate recall scores on verbal episodic memory tests and visual learning tests. In the control group, there were direct correlations only between overall cognitive performance (as assessed with the MMSE) and the volume of right hippocampus, and between the total score on the visual verbal learning test and the volume of the right and left parahippocampal gyrus. Conclusions: These findings highlight different patterns of relationship between cognitive performance and volumes of medial temporal structures in depressed individuals and healthy elderly subjects. The direct correlation between delayed visual verbal memory recall scores with left parahippocampal volumes specifically in elderly depressed individuals provides support to the view that depression in elderly populations may be a risk factor for dementia. (C) 2009 Elsevier Inc. All rights reserved.

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PURPOSE. To evaluate the effect of disease severity on the diagnostic accuracy of the Cirrus Optical Coherence Tomograph (Cirrus HD-OCT; Carl Zeiss Meditec, Inc., Dublin, CA) for glaucoma detection. METHODS. One hundred thirty-five glaucomatous eyes of 99 patients and 79 normal eyes of 47 control subjects were recruited from the longitudinal Diagnostic Innovations in Glaucoma Study (DIGS). The severity of the disease was graded based on the visual field index (VFI) from standard automated perimetry. Imaging of the retinal nerve fiber layer (RNFL) was obtained using the optic disc cube protocol available on the Cirrus HD-OCT. Pooled receiver operating characteristic (ROC) curves were initially obtained for each parameter of the Cirrus HD-OCT. The effect of disease severity on diagnostic performance was evaluated by fitting an ROC regression model, with VFI used as a covariate, and calculating the area under the ROC curve (AUCs) for different levels of disease severity. RESULTS. The largest pooled AUCs were for average thickness (0.892), inferior quadrant thickness (0.881), and superior quadrant thickness (0.874). Disease severity had a significant influence on the detection of glaucoma. For the average RNFL thickness parameter, AUCs were 0.962, 0.932, 0.886, and 0.822 for VFIs of 70%, 80%, 90%, and 100%, respectively. CONCLUSIONS. Disease severity had a significant effect on the diagnostic performance of the Cirrus HD-OCT and thus should be considered when interpreting results from this device and when considering the potential applications of this instrument for diagnosing glaucoma in the various clinical settings. (Invest Ophthalmol Vis Sci. 2010;51:4104-4109) DOI:10.1167/iovs.094716

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Background: The relation between left ventricular filing velocities determined by Doppler echocardiography and autonomic nervous system function assessed by heart rate variability (HRV) is unclear. The aim of this study was to evaluate the influence of the autonomic nervous system assessed by the time and frequency domain indices of HRV in the Doppler indices of left ventricular diastolic filling velocities in patients without heart disease. Methods: We studied 451 healthy individuals (255 female [56.4%]) with normal blood pressure, electrocardiogram, chest x-ray, and treadmill electrocardiographic exercise stress test results, with a mean age of 43 +/- 12 (range 15-82) years, who underwent transthoracic Doppler echocardiography and 24-hour electrocardiographic ambulatory monitoring. We studied indices of HRV on time (standard deviation [SD] of all normal sinus RR intervals during 24 hours, SD of averaged normal sinus RR intervals for all 5-minute segments, mean of the SD of all normal sinus RR intervals for all 5-minute segments, root-mean-square of the successive normal sinus RR interval difference, and percentage of successive normal sinus RR intervals > 50 ms) and frequency (low frequency, high frequency, very low frequency, low frequency/high frequency ratio) domains relative to peak flow velocity during rapid passive filling phase (E), atrial contraction (A), E/A ratio, E-wave deceleration time, and isovolumic relaxation time. Statistical analysis was performed with Pearson correlation and logistic regression. Results: Peak flow velocity during rapid passive filling phase (E) and atrial contraction (A), E/A ratio, and deceleration time of early mitral inflow did not demonstrate a significant correlation with indices of HRV in time and frequency domain. We found that the E/A ratio was < 1 in 45 individuals (10%). Individuals with an E/A ratio < 1 had lower indices of HRV in frequency domain (except low frequency/high frequency) and lower indices of the mean of the SD of all normal sinus RR intervals for all 5-minute segments, root-mean-square of the successive normal sinus RR interval difference, and percentage of successive normal sinus RR intervals > 50 ms in time domain. Logistic regression demonstrated that an E/A ratio < 1 was associated with lower HF. Conclusion: Individuals with no evidence of heart disease and an E/A ratio < 1 demonstrated a significant decrease in indexes of HRV associated with parasympathetic modulation. (J Am Soc Echocardiogr 2010;23: 762-5.)

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Data are reported on the background and performance of the K6 screening scale for serious mental illness (SMI) in the World Health Organization (WHO) World Mental Health (WMH) surveys. The K6 is a six-item scale developed to provide a brief valid screen for Diagnostic and Statistical Manual of Mental Disorders 4th edition (DSM-IV) SMI based on the criteria in the US ADAMHA Reorganization Act. Although methodological studies have documented good K6 validity in a number of countries, optimal scoring rules have never been proposed. Such rules are presented here based on analysis of K6 data in nationally or regionally representative WMH surveys in 14 countries (combined N = 41,770 respondents). Twelve-month prevalence of DSM-IV SMI was assessed with the fully-structured WHO Composite International Diagnostic Interview. Nested logistic regression analysis was used to generate estimates of the predicted probability of SMI for each respondent from K6 scores, taking into consideration the possibility of variable concordance as a function of respondent age, gender, education, and country. Concordance, assessed by calculating the area under the receiver operating characteristic curve, was generally substantial (median 0.83; range 0.76-0.89; inter-quartile range 0.81-0.85). Based on this result, optimal scaling rules are presented for use by investigators working with the K6 scale in the countries studied. Copyright (c) 2010 John Wiley & Sons, Ltd.

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Aims. To investigate the effects of using bromazepam on the relative power in alpha while performing a typing task. Bearing in mind the particularities of each brain hemisphere, our hypothesis was that measuring the relative power would allow its to investigate the effects of bromazepam oil specific areas of the cortex. More, specifically, we expected to observe different patterns of powers in sensory-motor integration, attention and activation processes. Subjects and methods. The sample was made up of 39 subjects (15 males and 24 females) with a mean age of 30 +/- 10 years. The control (placebo) and experimental (3 mg and 6 mg of bromazepam) groups were trained ill the typing task with a randomised double-blind model. Results. A three-way ANOVA and Scheffe test were used to analyse interactions between the factors condition and moment, and between condition and sector Conclusions. The doses used ill this study facilitated motor performance of the typing task. Ill this study, the use of the drug did not prevent learning of the task, but it did appear to concentrate mental effort on more restricted and specific aspects of typing. It also seemed to influence the rhythm and effectiveness of the operations performed during mechanisms related to the encoding and storage often, information. Likewise, a predominance of activity was observed in the left (dominant) frontal area in the 3 mg bromazepam group, which indicates that this close of the drug affords the subject a greater degree of directionality of cortical activity for planning and performing the task. [REV NEUROL 2009; 49: 295-9]

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Background: Dementia screening in elderly people with low education can be difficult to implement. For these subjects, informant reports using the long (L) (26 items) and short (C) (16 items) versions of the Informant Questionnaire on Cognitive Decline in the Elderly (IQCODE) can be useful. The objective of the present study was to investigate the performance of Brazilian versions of the IQCODE L, S and a new short version (SBr) (15 items) in comparison with the Mini-mental State Examination (MMSE) for dementia screening in elderly people with low education. Methods: Thirty-four patients with mild to moderate dementia, diagnosed according to ICD-10 criteria, and 57 controls were evaluated and divided into three groups based on their socioeconomic status and level of education. Patients were evaluated using the MMSE and the informants were interviewed using the IQCODE by interviewers blind to the clinical diagnosis. Results: Education was correlated with MMSE results (r = 0.280, p = 0.031), but not with the versions of the IQCODE. The performance of the instruments, evaluated by the ROC curves, was very similar, with good internal consistency (Cronbach`s alpha = 0.97). MMSE correctly classified 85.7% of the subjects while the three IQCODE versions (L, S and SBr) correctly classified 91.2% of the subjects. Conclusions: The long, short and the new short Brazilian IQCODE versions can be useful as a screening tool for mild and moderate patients with dementia in Brazil. The IQCODE is not biased by schooling, and it seems to be an adequate instrument for samples with low levels of education.

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Our objective is to verify the modulatory effects of bromazepam on EEG theta absolute power when subjects were submitted to a visuomotor task (i.e., car driver task). Sample was composed of 14 students (9 males and 5 females), right handed, with ages varying between 23 and 42 years (mean = 32.5 +/- 9.5), absence of mental or physical impairments, no psychoactive or psychotropic substance use and no neuromuscular disorders (screened by a clinical examination). The results showed an interaction between condition and electrodes (p=0.034) in favor of F8 electrode compared with F7 in both experimental conditions (t-test; p=0.001). Additionally, main effects were observed for condition (p=0.001), period (p=0.001) and electrodes (p=0.031) in favor of F4 electrode compared with F3. In conclusion, Br 6 mg of bromazepam may interfere in sensorimotor processes in the task performance in an unpredictable scenario allowing that certain visuospatial factors were predominant. Therefore, the results may reflect that bromazepam effects influence the performance of the involved areas because of the acquisition and integration of sensory stimuli processes until the development of a motor behavior based on the same stimuli. (C) 2009 Elsevier Ireland Ltd. All rights reserved.

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Fear of heights, or acrophobia, is one of the most frequent subtypes of specific phobia frequently associated to depression and other anxiety disorders. Previous evidence suggests a correlation between acrophobia and abnormalities in balance control, particularly involving the use of visual information to keep postural stability. This study investigates the hypotheses that (1) abnormalities in balance control are more frequent in individuals with acrophobia even when not exposed to heights, that (2) acrophobic symptoms are associated to abnormalities in visual perception of movement; and that (3) individuals with acrophobia are more sensitive to balance-cognition interactions. Thirty-one individuals with specific phobia of heights and thirty one non-phobic controls were compared using dynamic posturography and a manual tracking task. Acrophobics had poorer performance in both tasks, especially when carried out simultaneously. Previously described interference between posture control and cognitive activity seems to play a major role in these individuals. The presence of physiologic abnormalities is compatible with the hypothesis of a non-associative acquisition of fear of heights, i.e., not associated to previous traumatic events or other learning experiences. Clinically, this preliminary study corroborates the hypothesis that vestibular physical therapy can be particularly useful in treating individuals with fear of heights.