Receiver Operating Characteristic Curve Statistics Research Articles

Instrumento de Avaliação Fonológica: evidências de validade de construto

ABSTRACT Purpose To investigate evidence of construct validity for a Phonological Assessment Instrument for Brazilian Portuguese, based on the diagnostic data generated by its application from contrastive analysis and speech severity. Methods The sample consisted of 176 children, aged between five to nine years old. They were evaluated with the Phonological Assessment Instrument and then classified as having Speech Sound Disorder or in typical phonological development, comparing these results to the criteria described for the disorder in the DSM-5. The search for evidence of construct validity relied on the agreement between the two assessment methods while applying the Kappa Coefficient. To differentiate between groups, Student's t-test was used for independent samples. We sought to investigate the instrument indexes using the Receiver Operating Characteristic Curve statistics to obtain values for area, cut-off point, sensitivity, specificity, accuracy, and positive and negative predictive value. Results The instrument showed agreement and significant differentiation between the classifications. As for the performance parameters, it shows a cut-off point for diagnosis with results equal to or greater than 96.17%, an excellent area under the curve, as well as satisfactory percentages for the other analyses investigated. Conclusion The data indicated evidence for the construct validity of the Phonological Assessment Instrument, presenting a useful and valid contribution to the arsenal of clinical assessment and research involving the diagnosis of Speech Sound Disorder and, with its accuracy result, contributed to the properties of performance of instruments used in Speech, Language and Hearing Sciences.

Phonological Assessment Instrument: evidence of construct validity.

To investigate evidence of construct validity for a Phonological Assessment Instrument for Brazilian Portuguese, based on the diagnostic data generated by its application from contrastive analysis and speech severity. The sample consisted of 176 children, aged between five to nine years old. They were evaluated with the Phonological Assessment Instrument and then classified as having Speech Sound Disorder or in typical phonological development, comparing these results to the criteria described for the disorder in the DSM-5. The search for evidence of construct validity relied on the agreement between the two assessment methods while applying the Kappa Coefficient. To differentiate between groups, Student's t-test was used for independent samples. We sought to investigate the instrument indexes using the Receiver Operating Characteristic Curve statistics to obtain values for area, cut-off point, sensitivity, specificity, accuracy, and positive and negative predictive value. The instrument showed agreement and significant differentiation between the classifications. As for the performance parameters, it shows a cut-off point for diagnosis with results equal to or greater than 96.17%, an excellent area under the curve, as well as satisfactory percentages for the other analyses investigated. The data indicated evidence for the construct validity of the Phonological Assessment Instrument, presenting a useful and valid contribution to the arsenal of clinical assessment and research involving the diagnosis of Speech Sound Disorder and, with its accuracy result, contributed to the properties of performance of instruments used in Speech, Language and Hearing Sciences.

Dynamic multi-echo DCE- and DSC-MRI in rectal cancer: Low primary tumor Ktrans and ΔR2* peak are significantly associated with lymph node metastasis

To implement a dynamic contrast-based multi-echo MRI sequence in assessment of rectal cancer and evaluate associations between histopathologic data and the acquired dynamic contrast-enhanced (DCE) and dynamic susceptibility contrast (DSC) -MRI parameters. This pilot study reports results from 17 patients with resectable rectal cancer. Dynamic contrast-based multi-echo MRI (1.5T) was acquired using a three-dimensional multi-shot EPI sequence, yielding both DCE- and DSC-data following a single injection of contrast agent. The Institutional Review Board approved the study and all patients provided written informed consent. Quantitative analysis was performed by pharmacokinetic modeling on DCE data and tracer kinetic modeling on DSC data. Mann-Whitney U-test and receiver operating characteristics curve statistics was used to evaluate associations between histopathologic data and the acquired DCE- and DSC-MRI parameters. For patients with histologically confirmed nodal metastasis, the primary tumor demonstrated a significantly lower Ktrans and peak change in R2*, R2*-peakenh , than patients without nodal metastasis, showing a P-value of 0.010 and 0.005 for reader 1, and 0.043 and 0.019 for reader 2, respectively. This study shows the feasibility of acquiring DCE- and DSC-MRI in rectal cancer by dynamic multi-echo MRI. A significant association was found between both Ktrans and R2*-peakenh in the primary tumor and histological nodal status of the surgical specimen, which may improve stratification of patients to intensified multimodal treatment. 4 Technical Efficacy: Stage 2 J. MAGN. RESON. IMAGING 2017;46:194-206.

Anal sphincter trauma and anal incontinence in urogynecological patients.

To determine the prevalence of evidence of residual obstetric anal sphincter injury, to evaluate its association with anal incontinence (AI) and to establish minimal diagnostic criteria for significant (residual) external anal sphincter (EAS) trauma. This was a retrospective analysis of ultrasound volume datasets of 501 patients attending a tertiary urogynecological unit. All patients underwent a standardized interview including determination of St Mark's score for those presenting with AI. Tomographic ultrasound imaging (TUI) was used to evaluate the EAS and the internal anal sphincter (IAS). Among a total of 501 women, significant EAS and IAS defects were found in 88 and 59, respectively, and AI was reported by 69 (14%). Optimal prediction of AI was achieved using a model that included four abnormal slices of the EAS on TUI. IAS defects were found to be less likely to be associated with AI. In a multivariable model controlling for age and IAS trauma, the presence of at least four abnormal slices gave an 18-fold (95% CI, 9-36; P < 0.0001) increase in the likelihood of AI, compared with those with fewer than four abnormal slices. Using receiver-operating characteristics curve statistics, this model yielded an area under the curve of 0.86 (95% CI, 0.80-0.92). Both AI and significant EAS trauma are common in patients attending urogynecological units, and are strongly associated with each other. Abnormalities of the IAS seem to be less important in predicting AI. Our data support the practice of using, as a minimal criterion, defects present in four of the six slices on TUI for the diagnosis of significant EAS trauma.

The Surveillance, Epidemiology, and End Results Cancer Survival Calculator SEER*CSC: validation in a managed care setting.

Nomograms for prostate and colorectal cancer are included in the Surveillance, Epidemiology, and End Results (SEER) Cancer Survival Calculator, under development by the National Cancer Institute. They are based on the National Cancer Institute's SEER data, coupled with Medicare data, to estimate the probabilities of surviving or dying from cancer or from other causes based on a set of patient and tumor characteristics. The nomograms provide estimates of survival that are specific to the characteristics of the tumor, age, race, gender, and the overall health of a patient. These nomograms have been internally validated using the SEER data. In this paper, we externally validate the nomograms using data from Kaiser Permanente Colorado. The SEER Cancer Survival Calculator was externally validated using time-dependent area under the Receiver Operating Characteristic curve statistics and calibration plots for retrospective cohorts of 1102 prostate cancer and 990 colorectal cancer patients from Kaiser Permanente Colorado. The time-dependent area under the Receiver Operating Characteristic curve statistics were computed for one, three, five, seven, and 10 year(s) postdiagnosis for prostate and colorectal cancer and ranged from 0.77 to 0.89 for death from cancer and from 0.72 to 0.81 for death from other causes. The calibration plots indicated a very good fit of the model for death from cancer for colorectal cancer and for the higher risk group for prostate cancer. For the lower risk groups for prostate cancer (<10% chance of dying of prostate cancer in 10 years), the model predicted slightly worse prognosis than observed. Except for the lowest risk group for colorectal cancer, the models for death from other causes for both prostate and colorectal cancer predicted slightly worse prognosis than observed. The results of the external validation indicated that the colorectal and prostate cancer nomograms are reliable tools for physicians and patients to use to obtain information on prognosis and assist in establishing priorities for both treatment of the cancer and other conditions, particularly when a patient is elderly and/or has significant comorbidities. The slightly better than predicted risk of death from other causes in a health maintenance organization (HMO) setting may be due to an overall healthier population and the integrated management of disease relative to the overall population (as represented by SEER).

Odontometric sex variation in Malaysians with application to sex prediction

Information about the sex of individuals is important for human identification. This study was conducted to quantify classification rates of sex prediction models for Malaysians using odontometric profiles. Mesiodistal (MD) and buccolingual (BL) crown dimensions of the permanent dentition were studied in 400 young adult Malaysians, giving a total of 28 tooth size variables. The sample consisted of three major ethnic groups, the Malays, Chinese and Tamils, since the aim was to assess sex dimorphism in Malaysians as a whole. Results showed that the mesiodistal diameter of the lower canine was the most sexually dimorphic dimension in Malaysian Malays and Tamils. Univariate analyses showed that the magnitude and pattern of sex dimorphism varies between these three ethnic groups, with Malaysian Chinese and Tamils being more dimorphic than the Malaysian Malays. Stepwise discriminant functions were generated bearing in mind their application in practical forensic situations. The range of classification rates was from 70.2% to 78.5% for the composite Malaysian group, and 83.8%, 77.9%, 72.4% for Malaysian Chinese, Malays and Tamils, respectively. The ‘Area Under the Receiver Operating Characteristic Curve statistics’ indicated good classification rates for three prediction models obtained using a combination of all tooth size variables, mandibular teeth, and mesiodistal dimensions in the composite Malaysian group, and for all tooth size variables in each ethnic group. The present study provides strong support for the value of odontometry as an adjunct scientific method for sex prediction in human identification.

Performance-based assessments and demand for personal care in older Japanese people: a cross-sectional study

ObjectivesTo identify appropriate clinical tests for determining the demand for personal care in older Japanese people.DesignCross-sectional observation study.SettingObu Study of Health Promotion for the Elderly (Obu, Aichi) and Tsukui Ordered...

Duration of persistent abnormal ductus venosus flow and its impact on perinatal outcome in fetal growth restriction

To study if the duration of individual Doppler abnormalities is an independent predictor of adverse outcome in fetal growth restriction (FGR) caused by placental dysfunction. This was a secondary analysis of patients with FGR (abdominal circumference < 5(th) percentile and umbilical artery (UA) pulsatility index (PI) elevation) who had at least three examinations before delivery. Days of duration of absent/reversed UA end-diastolic velocity (UA-AREDV), low middle cerebral artery PI (brain sparing), ductus venosus (DV) and umbilical vein Doppler abnormalities were related to stillbirth, major neonatal morbidity and intact survival. One hundred and seventy-seven study participants underwent a total of 1069 examinations. The duration of an absent/reversed a-wave in the DV (DV-RAV) was significantly higher in stillbirths (median, 6 days) compared with intact survivors and those with major morbidity (median, 0 days for both; P = 0.006 and P = 0.001, respectively). Duration of brain sparing was also longer in stillbirth cases compared with intact survivors (median, 19 days vs. 9 days, P = 0.02). Stepwise multinomial logistic regression showed that gestational age at delivery was a significant codeterminant of outcome for all arterial Doppler abnormalities when the DV a-wave was antegrade. However, when present, the duration of DV-RAV was the only contributor to stillbirth (probability of stillbirth = 1/(1 + exp - (interval to delivery × 1.03 - 2.28)), r2 = 0.73). Receiver-operating characteristics curve statistics showed that a DV-RAV for > 7 days predicted stillbirth (100% sensitivity, 80% specificity, likelihood ratio = 5.0, P < 0.0001). In contrast, neither neonatal death nor neonatal morbidity was predicted by the days of persistent DV-RAV. The duration of absent or reversed flow during atrial systole in the DV is a strong predictor of stillbirth that is independent of gestational age. While prematurity remains the strongest predictor of neonatal risks it is unlikely that pregnancy can be prolonged by more than 1 week in this setting.

Clinical course and mortality risk factors in critically ill children requiring continuous renal replacement therapy

To study the clinical course in children requiring continuous renal replacement therapy (CRRT) and to analyse factors associated with mortality. Prospective observational study. Paediatric intensive care department of a tertiary university hospital. Critically ill children with CRRT were included in the study. Continuous renal replacement therapy. Univariate and multivariate analyses were performed to analyse the influence of each factor on mortality. The ability of the PRISM, PIM II and PELOD severity of illness scores to predict mortality was tested using receiver-operating characteristic curve statistics. A total of 174 children aged between 1 month and 22 years were treated with CRRT. Mortality was 35.6%, and multiorgan failure and haemodynamic disturbances were the principal causes of death. Mortality was higher in children less than 12 months of age (44.7%; P = 0.037) and in patients with a diagnosis of sepsis (44.1%; P = 0.001). Haemodynamic disturbances at the time of starting CRRT (hypotension or need for adrenaline >0.6 microg/kg/min) and the presence of multiorgan failure were the factors associated with an increased risk of mortality. The PRISM scale was the severity score with the best predictive capacity, although all three scales underestimated the actual mortality. Mortality in children who require CRRT is high. Haemodynamic disturbances and the presence of multiorgan failure at the time of starting the technique are the factors associated with a higher mortality. The clinical severity scores underestimate mortality in children requiring CRRT.

Nonparametric and Semiparametric Group Sequential Methods for Comparing Accuracy of Diagnostic Tests

Comparison of the accuracy of two diagnostic tests using the receiver operating characteristic (ROC) curves from two diagnostic tests has been typically conducted using fixed sample designs. On the other hand, the human experimentation inherent in a comparison of diagnostic modalities argues for periodic monitoring of the accruing data to address many issues related to the ethics and efficiency of the medical study. To date, very little research has been done on the use of sequential sampling plans for comparative ROC studies, even when these studies may use expensive and unsafe diagnostic procedures. In this article we propose a nonparametric group sequential design plan. The nonparametric sequential method adapts a nonparametric family of weighted area under the ROC curve statistics (Wieand et al., 1989, Biometrika 76, 585-592) and a group sequential sampling plan. We illustrate the implementation of this nonparametric approach for sequentially comparing ROC curves in the context of diagnostic screening for nonsmall-cell lung cancer. We also describe a semiparametric sequential method based on proportional hazard models. We compare the statistical properties of the nonparametric approach with alternative semiparametric and parametric analyses in simulation studies. The results show the nonparametric approach is robust to model misspecification and has excellent finite-sample performance.