Symptomatic Classes Research Articles

A latent class analysis to empirically describe eating disorders through developmental stages.

The current standards for classifying eating disorders were primarily informed by adult, clinical study populations, while it is unknown whether an empirically based classification system can be supported across preadolescence through young adulthood. Using latent class analyses, we sought to empirically classify disordered eating in females from preadolescence to young adulthood, and assess the association between classes and adverse outcomes. Latent class models were fit using observations from the 9,039 girls participating in the growing up today study, an on-going cohort following participants annually or biennially since 1996 when they were ages 9-14 years. Associations between classes and drug use, binge drinking, and depressive symptoms were assessed using generalized estimating equations. Across age groups, there was evidence of six classes: a large asymptomatic class, a class characterized by shape/weight concerns, a class characterized by overeating without loss of control, and three resembling full and subthreshold binge eating disorder, purging disorder, and bulimia nervosa. Relative prevalences of classes varied across developmental stages, with symptomatic classes increasing in prevalence with increasing age. Symptomatic classes were associated with concurrent and incident drug use, binge drinking, and high depressive symptoms. A classification system resembling broader definitions of DSM-5 diagnoses along with two further subclinical symptomatic classes may be a useful framework for studying disordered eating among adolescent and young adult females.

Latent classes of PTSD symptoms in Iraq and Afghanistan female veterans

BackgroundRecent studies have used latent class analysis (LCA) to identify subgroups of individuals who share similar patterns of PTSD symptom endorsement; however, further study is needed among female veterans, whose PTSD symptom expression may vary from that of their male counterparts. The current study examined latent PTSD symptom classes in female veterans who returned from recent military service in Iraq and Afghanistan, and explored military and demographic variables associated with distinct PTSD symptom presentations. MethodsA retrospective analysis was conducted using existing medical records from female Iraq and Afghanistan veterans who were new users of VA mental health outpatient (MHO) care, had received a PTSD diagnosis anytime during the post-deployment period, and completed the PTSD checklist within 30 days of their first MHO visit (N=2425). ResultsThe LCA results identified four latent classes of PTSD symptom profiles in the sample: High Symptom, Intermediate Symptom, Intermediate Symptom with High Emotional Numbing (EN), and Low Symptom. Race/ethnicity, age, time since last deployment, and distance from a VA facility emerged as predictors of PTSD symptom presentation. LimitationsThe current study was cross-sectional and utilized administrative data. The results may not be generalizable to female veterans from other service eras. ConclusionsLonger times between end of last deployment and initiation of MHO services were associated with more symptomatic classes. Exploration of PTSD symptom presentation may enhance our understanding of the service needs of female veterans with PTSD, and suggests potential benefits to engaging veterans in MHO soon after last deployment.

DSM-5 latent classes of alcohol users in a population-based sample: Results from the São Paulo Megacity Mental Health Survey, Brazil

BackgroundWe aimed to identify different categorical phenotypes based upon the DSM-V criteria of alcohol use disorders (AUD) among alcohol users who had at least one drink per week in the past year (n=948). MethodsData are from the São Paulo Megacity Mental Health Survey collected in 2005–2007, as part of the World Mental Health Survey Initiative. A latent class analysis of the 11 DSM-5-AUD criteria was performed using Mplus, taking into account complex survey design features. Weighted logistic regression models were used to examine demographic correlates of the DSM-5-AUD latent classes. ResultsThe best latent-class model was a three-class model. We found a “non-symptomatic class” (69.7%), a “use in larger amounts class” (23.2%), defined by high probability (>70%) of the “use in larger amounts” criterion only, and a “high-moderate symptomatic class” (7.1%), defined by high-moderate probability of all the 11 AUD criteria. Compared to those in the non-symptomatic class, individuals in the “high-moderate symptomatic class” were more likely to have been married, have lower educational attainment and to be unemployed or in non-regular/informal employment. Those on the “use in larger amounts class” were more likely to have been married or never married. ConclusionThe two symptomatic classes clearly represented the dimensionality of the new proposed AUD criteria, and could be more specifically targeted by different prevention or treatment strategies. DSM-5-AUD has the advantage of shedding light on risky drinkers included in the “use in larger amounts class”, allowing for preventive interventions, which will reach a large number of individuals.

P.2.d.006 The MANACOR study on treatment effectiveness in mania

Childhood subthreshold manic symptoms may represent a state of developmental vulnerability to Bipolar Disorder (BD) and may also be associated with other adverse psychiatric outcomes. To test this hypothesis we examined the structure and predictive value of childhood subthreshold manic symptoms for common psychiatric disorders presenting by early adulthood.Subthreshold manic symptoms at age 11 years and lifetime clinical outcomes by age 19 years were ascertained in the TRacking Adolescents’ Individual Lives Survey (TRAILS), a prospective Dutch community cohort. We used latent class analysis to identify subthreshold manic symptom profiles at baseline. The association between class membership and subsequent clinical diagnoses of BD (comprising BD-I, BD-II, mania and hypomania), depressive, anxiety and substance abuse disorders was determined using Cox proportional-hazard ratio (HR) models.At age 11 years, we identified a normative (n=916; 47%), a mildly symptomatic (n=843; 43%) and a highly symptomatic class (n=198; 10%). Referenced to the normative class, the sex- and age-adjusted risk of new-onset BD by the age of 19 years was significantly increased in the mildly (HR=2.01, 95%CI 1.13–3.59) and highly symptomatic classes (HR=5.02, 95%CI 2.48–10.16). These estimates remained significant after further adjustments for cognitive and family function, parental socioeconomic status, parental psychiatric morbidity, and comorbid disorders at baseline (p-value for linear trend across classes<0.01). Class membership did not show significant associations with incident depressive, anxiety and substance abuse disorders in the fully adjusted regression models.The period of risk for adult-onset BD extends beyond the observational period of the study.Elevated childhood subthreshold manic symptoms are associated with increased risk of BD by early adulthood and are therefore a potentially useful phenotype for the early identification of at-risk individuals.

A Critical Protection Level Derived from Dengue Infection Mathematical Model Considering Asymptomatic and Symptomatic Classes

In this paper we formulate a model of dengue fever transmission by considering the presence of asymptomatic and symptomatic compartments. The model takes the form as a system of differential equations representing a host-vector SIR (Susceptible – Infective -Recovered) disease transmission. It is assumed that both host and vector populations are constant. It is also assumed that reinfection of recovered hosts by the disease is possible due to a wanning immunity in human body. We analyze the model to determine the qualitative behavior of the model solution and use the concept of effective basic reproduction number (ℜp) as a control criteria of the disease transmission. The effect of mosquito biting protection (e.g. by using insect repellent) is also considered. We compute the long-term ratio of the asymptomatic and symptomatic classes and show a condition for which the iceberg phenomenon could appear.

Gender differences in symptomatic profiles of depression: Results from the São Paulo Megacity Mental Health Survey

BackgroundFew studies have investigated symptomatic subtypes of depression and their correlates by gender. MethodsData are from the São Paulo Megacity Mental Health Survey. Symptom profiles of 1207 subjects (864 women; 343 men) based upon symptoms of the worst depressive episode in lifetime were examined through latent class analysis. Correlates of gender-specific latent classes were analyzed by logistic regression. ResultsFor both men and women, a 3-class model was the best solution. A mild class was found in both genders (41.1% in women; 40.1% in men). Gender differences appeared in the most symptomatic classes. In women, they were labeled melancholic (39.3%) and atypical (19.5%), differing among each other in somatic/vegetative symptoms. The melancholic class presented inhibition and eating/sleeping symptoms in the direction of decreasing, whereas the atypical class had increased appetite/weight, and hypersomnia. For men, symptoms that differentiate the two most symptomatic classes were related to psychomotor activity: a melancholic/psychomotor retarded (40.4%) and agitated depression (19.6%). The highest between-class proportion of agitation and racing thoughts was found among men in the agitated class, with similarity to bipolar mixed state. LimitationsAnalyses were restricted to those who endorsed questions about their worst lifetime depressive episode; the standardized assessment by lay interviewers; the small male sample size. ConclusionsThe construct of depression of current classifications is heterogeneous at the symptom level, where gender different subtypes can be identified. These symptom profiles have potential implications for the nosology and the therapeutics of depression.

Understanding symptomatology of atherosclerotic plaque by image-based tissue characterization

Characterization of carotid atherosclerosis and classification into either symptomatic or asymptomatic is crucial in terms of diagnosis and treatment planning for a range of cardiovascular diseases. This paper presents a computer-aided diagnosis (CAD) system (Atheromatic) that analyzes ultrasound images and classifies them into symptomatic and asymptomatic. The classification result is based on a combination of discrete wavelet transform, higher order spectra (HOS) and textural features. In this study, we compare support vector machine (SVM) classifiers with different kernels. The classifier with a radial basis function (RBF) kernel achieved an average accuracy of 91.7% as well as a sensitivity of 97%, and specificity of 80%. Thus, it is evident that the selected features and the classifier combination can efficiently categorize plaques into symptomatic and asymptomatic classes. Moreover, a novel symptomatic asymptomatic carotid index (SACI), which is an integrated index that is based on the significant features, has been proposed in this work. Each analyzed ultrasound image yields on SACI number. A high SACI value indicates that the image shows symptomatic and low value indicates asymptomatic plaques. We hope this SACI can support vascular surgeons during routine screening for asymptomatic plaques.

Atherosclerotic Risk Stratification Strategy for Carotid Arteries Using Texture-Based Features

Plaques in the carotid artery result in stenosis, which is one of the main causes for stroke. Patients have to be carefully selected for stenosis treatments as they carry some risk. Since patients with symptomatic plaques have greater risk for strokes, an objective classification technique that classifies the plaques into symptomatic and asymptomatic classes is needed. We present a computer aided diagnostic (CAD) based ultrasound characterization methodology (a class of Atheromatic systems) that classifies the patient into symptomatic and asymptomatic classes using two kinds of datasets: (1) plaque regions in ultrasound carotids segmented semi-automatically and (2) far wall gray-scale intima-media thickness (IMT) regions along the common carotid artery segmented automatically. For both kinds of datasets, the protocol consists of estimating texture-based features in frameworks of local binary patterns (LBP) and Law’s texture energy (LTE) and applying these features for obtaining the training parameters, which are then used for classification. Our database consists of 150 asymptomatic and 196 symptomatic plaque regions and 342 IMT wall regions. When using the Atheromatic-based system on semiautomatically determined plaque regions, support vector machine (SVM) classifier was adapted with highest accuracy of 83%. The accuracy registered was 89.5% on the far wall gray-scale IMT regions when using SVM, K-nearest neighbor (KNN) or radial basis probabilistic neural network (RBPNN) classifiers. LBP/LTE-based techniques on both kinds of carotid datasets are noninvasive, fast, objective and cost-effective for plaque characterization and, hence, will add more value to the existing carotid plaque diagnostics protocol. We have also proposed an index for each type of datasets: AtheromaticPi, for carotid plaque region, and AtheromaticWi, for IMT carotid wall region, based on the combination of the respective significant features. These indices show a separation between symptomatic and asymptomatic by 4.53 units and 4.42 units, respectively, thereby supporting the texture hypothesis classification.

Distribution of First-Detected Atrial Fibrillation Patients Without Structural Heart Diseases in Symptom Classifications

The characteristics and prognosis of patients with first-detected atrial fibrillation (AF) in Japan remain unclear. First-detected AF patients without structural heart disease (n=289) were reviewed with regard to 2 symptom classifications (CCS-SAF and EHRA). In both classifications, asymptomatic patients comprised ≈40% of the patients, and patients in the most symptomatic class (≈6%) had peculiar characteristics and poor prognosis. In other symptomatic classes, symptoms affected the treatment strategy without a significant difference in the patients' backgrounds and prognosis. This is the first report to describe the distribution, characteristics and outcomes of first-detected AF patients according to symptom classifications.

Latent class analysis of co-morbidity in the Adult Psychiatric Morbidity Survey in England 2007: implications for DSM-5 and ICD-11

Psychiatric co-morbidity is complex and ubiquitous. Our aim was to describe the extent, nature and patterning of psychiatric co-morbidity within a representative sample of the adult population of England, using latent class analysis. Data were used from the 2007 Adult Psychiatric Morbidity Survey, a two-phase national household survey undertaken in 2007 comprising 7325 participants aged 16 years and older living in private households in England. The presence of 15 common mental health and behavioural problems was ascertained using standardized clinical and validated self-report measures, including three anxiety disorders, depressive episode, mixed anxiety depressive disorder, psychosis, antisocial and borderline personality disorders, eating disorders, post-traumatic stress disorder, attention deficit disorder, alcohol and drug dependencies, problem gambling and attempted suicide. A four-class model provided the most parsimonious and informative explanation of the data. Most participants (81.6%) were assigned to a non-symptomatic or 'Unaffected' class. The remainder were classified into three qualitatively different symptomatic classes: 'Co-thymia' (12.4%), 'Highly Co-morbid' (5.0%) and 'Addictions' (1.0%). Classes differed in mean numbers of conditions and impairments in social functioning, and these dimensions were correlated. Our findings confirm that mental disorders typically co-occur and are concentrated in a relatively small number of individuals. Conditions associated with the highest levels of disability, mortality and cost--psychosis, suicidality and personality disorders--are often co-morbid with more common conditions. This needs to be recognized when planning services and when considering aetiology.

Age Structured Model for Symptomatic and Asymptomatic Infections of Dengue Disease

Age structure and the emergence of symptom for dengue infection are considered in this study. The transmission model is formulated to see the transmission of this disease. The human population is separated into juvenile and adult classes but only juvenile class being susceptible to infection by the disease. Infectious juvenile human is divided into symptomatic and asymptomatic classes. The transmission probabilities of dengue virus from vector to human are difference to become symptomatic and asymptomatic classes. The standard dynamical analysis method is used for analyzing this model. The basic reproduction number is obtained. Numerical simulations are used to show these results. The alternative way for controlling this disease is discussed in the term of threshold condition.

The Validity of an Empirical Delineation of Heterogeneity in Chronic Unexplained Fatigue

To validate a latent class structure derived empirically from a clinical data set obtained from persons with chronic medically unexplained fatigue. The strategies utilized in this validation study included: recalculating latent class analysis (LCA) results varying random seeds and the number of initial random starting sets; recalculating LCA results by substituting alternate variables to demonstrate a robust solution; determining the statistical significance of between-class differences on disability, fatigue and demographic measures omitted from the data set used for LCA; cross-classifying class membership using established Centers for Disease Control and Prevention (CDC) research criteria for chronic fatigue syndrome (CFS) to compare the relative proportions of subjects designated CFS, chronic fatigue (not CFS) or healthy controls captured by the latent classes. Recalculation of results and substitution of variables for low-loading variables demonstrated a robust LCA result. Highly significant between-class differences were confirmed between Class 2 (well) and those interpreted as ill/fatigued. Analysis of between-class differences for the fatigue groups revealed significant differences for all disability and fatigue variables, but with equivalent levels of reported activity and reduction in motivation. Cross-classification against established CDC criteria demonstrated that 89% of subjects constituting Class 2 (well) were indeed nonfatigued controls. A general tendency for grouping CFS cases in the multiple symptomatic classes was noted. This study established reasonably good validity for an empirically-derived latent class solution reflecting considerable heterogeneity among subjects with medically unexplained chronic fatigue. This work strengthens the growing understanding of CFS as a heterogeneous entity comprised of several conditions with different underlying pathophysiological mechanisms.

Comparative evaluation of despeckle filtering in ultrasound imaging of the carotid artery

It is well-known that speckle is a multiplicative noise that degrades the visual evaluation in ultrasound imaging. The recent advancements in ultrasound instrumentation and portable ultrasound devices necessitate the need of more robust despeckling techniques for enhanced ultrasound medical imaging for both routine clinical practice and teleconsultation. The objective of this work was to carry out a comparative evaluation of despeckle filtering based on texture analysis, image quality evaluation metrics, and visual evaluation by medical experts in the assessment of 440 (220 asymptomatic and 220 symptomatic) ultrasound images of the carotid artery bifurcation. In this paper a total of 10 despeckle filters were evaluated based on local statistics, median filtering, pixel homogeneity, geometric filtering, homomorphic filtering, anisotropic diffusion, nonlinear coherence diffusion, and wavelet filtering. The results of this study suggest that the first order statistics filter lsmv, gave the best performance, followed by the geometric filter gf4d, and the homogeneous mask area filter lsminsc. These filters improved the class separation between the asymptomatic and the symptomatic classes based on the statistics of the extracted texture features, gave only a marginal improvement in the classification success rate, and improved the visual assessment carried out by the two experts. More specifically, filters lsmv or gf4d can be used for despeckling asymptomatic images in which the expert is interested mainly in the plaque composition and texture analysis; and filters lsmv, gf4d, or lsminsc can be used for the despeckling of symptomatic images in which the expert is interested in identifying the degree of stenosis and the plaque borders. The proper selection of a despeckle filter is very important in the enhancement of ultrasonic imaging of the carotid artery. Further work is needed to evaluate at a larger scale and in clinical practice the performance of the proposed despeckle filters in the automated segmentation, texture analysis, and classification of carotid ultrasound imaging.

Remote Detection of Rhizomania in Sugar Beets

ABSTRACT As a prelude to remote sensing of rhizomania, hyper-spectral leaf reflectance and multi-spectral canopy reflectance were used to study the physiological differences between healthy sugar beets and beets infested with Beet necrotic yellow vein virus. This study was conducted over time in the presence of declining nitrogen levels. Total leaf nitrogen was significantly lower in symptomatic beets than in healthy beets. Chlorophyll and carotenoid levels were reduced in symptomatic beets. Vegetative indices calculated from leaf spectra showed reductions in chlorophyll and carotenoids in symptomatic beets. Betacyanin levels estimated from leaf spectra were decreased at the end of the 2000 season and not in 2001. The ratio of betacyanins to chlorophyll, estimated from canopy spectra, was increased in symptomatic beets at four of seven sampling dates. Differences in betacyanin and carotenoid levels appeared to be related to disease and not nitrogen content. Vegetative indices calculated from multi-spectral canopy spectra supported results from leaf spectra. Logistic regression models that incorporate vegetative indices and reflectance correctly predicted 88.8% of the observations from leaf spectra and 87.9% of the observations for canopy reflectance into healthy or symptomatic classes. Classification was best in August with a gradual decrease in accuracy until harvest. These results indicate that remote sensing technologies can facilitate detection of rhizomania.

Temporal progression of alcohol dependence symptoms in the U.S. household population: results from the National Comorbidity Survey.

General population data are presented on patterns and predictors of temporal progression of alcohol dependence symptoms in the general population. The data come from the National Comorbidity Survey, a nationally representative general population survey of respondents ages 15-54. Lifetime symptom classes were estimated with latent class analysis (LCA). A 4-class LCA solution, including a 1st asymptomatic class and 3 progressively more serious symptomatic classes, was found to fit the data. Probability of initial symptom onset among drinkers was found to be highest in the 10-24 age range, to be higher among men than women, and to have increased dramatically in the past 4 decades. Age, gender, and cohort effects were less powerful in predicting symptom progression. A narrowing of the gender difference over time was due largely to a convergence in initial symptom onset among men and women ages 10-24. These results suggest that a rise in initial problems was more important than an increase in the transition from problems to dependence in accounting for the growing prevalence of alcohol dependence during the post-World War II years in the United States.

The role of the distribution and anatomic extent of reflux in the development of signs and symptoms in chronic venous insufficiency

The purpose of this study was to identify the distribution of venous reflux in patients with different patterns of reflux with each class. Color-flow duplex imaging was used to evaluate the entire venous system from groin to ankle in 465 patients (594 limbs) belonging to different clinical CVI classes (0, 1, 2, and 3). A history of previous superficial thrombophlebitis was present in five limbs and past deep vein thrombosis in 70. One hundred seventy eight (30%) limbs were normal and the remaining 416 (70%) had venous incompetence. Deep reflux was present exclusively in 19 limbs (3.2%), and the perforation system alone was involved in only three limbs (0.5%). However, isolated superficial incompetence was seen in 186 limbs (31.3%) and a combination of superficial with perforating alone was involved in 45 (7.6%). Incompetence in all three systems was seen in 99 extremities (16.7%). In addition, the superficial system was involved in 390 limbs, the perforators in 151, and the deep system in 178 limbs. Only a small percentage of those in class 0 had reflux, and most of them had a single site of incompetence. In class 1 the majority of the limbs had superficial reflux (90.3%), 10.3% of the limbs had deep venous reflux, and 6.9% were competent. Reflux in the superficial system was only seen in 80.7% of the limbs in class 1 and in one fifth of the limbs in classes 2 and 3. Isolated deep or perforated incompetence was rare in all classes. Variable combined patterns of reflux were seen more often in classes 2 and 3 (p < 0.0001). In classes 2 and 3 there were no differences in the number of incompetent sites in the superficial and deep venous systems or the patterns of reflux (p > 0.1). The number of incompetent perforators in class 3 tended to be higher than that in class 2, especially in the below-knee segment, but no significant differences were seen. Distal reflux was present in the majority of the limbs in all symptomatic classes (1, 2, and 3). The distribution and extent of reflux is strongly associated with clinical severity of CVI through class 2. Distal venous reflux is present in at least 80% of the symptomatic limbs. Deep venous thrombosis may not be a prerequisite for the development of skin changes or ulceration in about 75% of the limbs. Superficial venous surgery could be beneficial to at least one third of patients with skin changes or ulceration.

Decrease in frequency of anginal episodes by control of thrombin generation with low-dose heparin: A controlled cross-over randomized study

Increased thrombin generation is frequently associated with an increase in anginal activity. A cross-over, single-blind, completely randomized study was planned in order to evaluate whether the control of thrombin generation affected the increase in anginal activity. After discharge from the hospital, 24 patients (18 men and 6 women, aged 40 to 69 years) suffering from spontaneous angina were followed up to 12 months and were alternatively treated during two consecutive 6-month periods with calcium heparin, 12,500 IU by the subcutaneous route, or with placebo by the intramuscular route, in addition to the usual antianginal medications. Thrombin generation and clinical activity of angina were assessed every 15 days by measuring fibrinopeptide A (FPA) plasma levels and by grading in three classes (symptomiess, mildly symptomatic, and severely symptomatic) the anginal activity on the basis of the number and the time concentration of the ischemic attacks and ECG changes. Low-dose heparin treatment significantly reduced both the FPA plasma level (from 4.1 ± 3.7 to 2.3 ± 1.8 ng/ml, p < 0.001) and the clinical activity of angina. During heparin treatment, the frequency of the observations in the severely and mildly symptomatic classes decreased, respectively, by 53% and by 30%, whereas that in the symptomless class increased by 23% ( p < 0.001) in comparison with the period on placebo. Present results indicate that the control of thrombin generation obtained by low-dose heparin treatment favorably affects the degree of anginal activity in patients with spontaneous angina.