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PubMed1997

[Quality control in the therapy of chronic pain. Results obtained by a task force of the German Section of the International Association for the Study of Pain on psychological assessment of chronic pain. XI. Assessment and multiaxial classification of pain].

This paper reviews instruments in German language for the psychological assessment and classification of pain. Usually chronic pain syndromes are classified within the International Classification of Diseases (ICD). Instead of the psychiatric chapter of the ICD, it is possible to use the Diagnostic and Statistical Manual of Mental Disorders (DSM). The proposed classification system of the International Association of the Study of Pain (IASP) is based on a multiaxial solution. The numerous ways to classify chronic pain include many problems and limits, especially in the case of an interdisciplinary assessment. They provide no specific system for classifying pain syndromes. They are impractical to handle and restrict classifying pain as either somatogenic or psychogenic. It is not possible to describe both sides in one diagnosis without loss of information. As a result of this situation, a task force of the German Chapter of the International Association for the Study of Pain developed a Multiaxial Classification of Pain (Multiaxiale Schmerzklassifikation; MASK) as an advanced system of pain assessment and an alternative to the common classification systems. MASK embraces a somatic (MASK-S) and a psychological (MASK-P) part. Both parts constitute an 'interdisciplinary diagnosis'. MASK-S enables classifying a pain syndrome using hierarchical levels, with progredient specific degrees of differentiation. In addition there are 6 axes to describe pain syndromes qualitatively and quantitatively (e.g. localization, quality). The psychosocial part (MASK-P) embraces 5 main levels (1. behavioral, 2. emotional, 3. cognitive, 4. stress-related, 5. habitual personal factors) and 2 additional levels (6. functional coherence, 7. ICD/DSM-diagnosis additional). The MASK-P part of the diagnosis is composed of graduation on these levels. Differential axis of the pain syndromes are described phenomenologically and specifically. MASK provides the possibility of establishing an integrative, interdisciplinary diagnosis.

English Abstract↗
PubMed2004

Endosonographic detection of mediastinal lymph node metastasis in superficial carcinoma of the esophagus: assessment by type classification and histogram.

BACKGROUND: Endoscopic ultrasonography (EUS) has been shown to be useful for detecting lymph node metastasis in esophageal cancer. The evaluation of nodal metastasis requires both objective and subjective analyses. In the present study, mediastinal lymph nodes in superficial esophageal carcinoma (SEC) were examined by both EUS appearance and histography, using NIH image software. METHODS: One hundred and seventy-one lymph nodes of 56 patients with SEC were detected by EUS. These lymph nodes were diagnosed by type classification, based on boundary and internal echo, and by the construction of internal echo histograms using NIH image software. The results were compared with the histological findings. RESULTS: . The sensitivity, specificity, and accuracy in assessing mediastinal lymph node metastasis by type classification were 83.3%, 88.2%, and 87.7%, respectively. The mean and SD of the histogram correlated well with histological findings and type classification ( P < 0.0001). All lymph nodes with a mean value of less than 185 of the histogram were negative nodes. When positive nodes by type classification were reevaluated according to the threshold value of 185 using the histogram, the sensitivity, specificity, and accuracy improved to 83.3%, 100%, and 98.2%, respectively. CONCLUSIONS: Type classification assisted by histography improved the diagnostic accuracy of mediastinal lymph node metastasis in SEC.

Carcinoma, Squamous Cell↗
PubMed2002

The Adams classification for cadaveric discograms: inter- and intra-observer error in the clinical setting.

The Adams classification for discogram morphology is based on a cadaveric study. It provides the basis for several subsequent classifications proposed in the literature. However, little or no attention has been paid to its reproducibility in the clinical setting. The authors assessed the reliability of this classification using three independent observers of differing experience. One hundred and thirty-three discograms belonging to 71 patients with chronic low back pain were reviewed in a randomised and blinded manner. The morphological appearance at each discogram level was assessed and assigned a type according to the Adams classification. The exercise was repeated 3 weeks later. Respective inter- and intra-observer agreements were calculated in the standard fashion using the kappa statistic. Both inter- and intra-observer agreements were excellent (kappa= 0.77-0.85). The Adams grading system for discogram morphology is consistently reproducible amongst observers with differing levels of experience. It can be safely recommended in the clinical setting as a reliable classification.

Adult↗
PubMed2006

Evaluation of a Dallas Pain Questionnaire classification in relation to outcome in lumbar spinal fusion.

Several studies have suggested that psychosocial distress is an important predictor of negative outcome in lumbar spine surgery. Ozguler et al. [Spine 27:1783-1789, 2002, 18] described a classification tool for low back pain patients using the Dallas Pain Questionnaire (DPQ) which included a measure of distress. We wanted to evaluate the ability of this classification tool to predict the outcome in spinal fusion patients. Five hundred and sixty-six patients (239 men, 327 women; mean age 46, range 18-81) operated between 1992 and 2002, with a complete DPQ preoperatively and after a minimum of 1-year follow-up, were included. They were classified preoperatively and at follow-up into four groups: group 1 (slight disability), group 2 (intermediate disability), group 3 (major disability) and group 4 (major disability and emotional distress). Using logistic regression, seven predictor variables were investigated: age (-39 years/40-59 years/60+ years), Gender (male/female), Indication (spondylolisthesis/primary degeneration/secondary degeneration), Work status (working/without work or on sick leave/retired or pensioned), Duration of pain (less than 1 year/1-2 years/more than 2 years), Presence of radiating pain (yes/no) and disability/distress [intermediate disability (group 1-2)/major disability (group 3)/major disability and distress (group 4)]. The outcome variable was disability at follow-up (low = group1 + 2/high = group 3 + 4). Preoperative classification was group 1, 1%; group 2, 14%; group 3, 37%; group 4, 48%. Variables found to predict high disability at follow-up were secondary degeneration Odds Ratio (OR) 1.61 (P=0.020), being retired/pensioned OR 3.48 (P<0.0005), age between 40-59 years OR 1.68 (P=0.011), belonging to group 3 OR 2.69 (P=0.003) or belonging to group 4 OR 5.53 (P<0.0005). The classification based on the DPQ were able to identify lumbar spinal fusion patients with a considerable amount of psychological distress in their symptomatology. Furthermore, the presence of distress, as determined by this classification, was a highly significant risk factor for inferior outcome.

Adolescent↗
PubMed2006

On the classification and nomenclature of baculoviruses: a proposal for revision.

Recent evidence from genome sequence analyses demands a substantial revision of the taxonomy and classification of the family Baculoviridae. Comparisons of 29 baculovirus genomes indicated that baculovirus phylogeny followed the classification of the hosts more closely than morphological traits that have previously been used for classification of this virus family. On this basis, dipteran- and hymenopteran-specific nucleopolyhedroviruses (NPV) should be separated from lepidopteran-specific NPVs and accommodated into different genera. We propose a new classification and nomenclature for the genera within the baculovirus family. According to this proposal the updated classification should include four genera: Alphabaculovirus (lepidopteran-specific NPV), Betabaculovirus (lepidopteran-specific Granuloviruses), Gammabaculovirus (hymenopteran-specific NPV) and Deltabaculovirus (dipteran-specific NPV).

Baculoviridae↗
PubMed2004

Impact of descriptor vector scaling on the classification of drugs and nondrugs with artificial neural networks.

The influence of preprocessing of molecular descriptor vectors for solving classification tasks was analyzed for drug/nondrug classification by artificial neural networks. Molecular properties were used to form descriptor vectors. Two types of neural networks were used, supervised multilayer neural nets trained with the back-propagation algorithm, and unsupervised self-organizing maps (Kohonen maps). Data were preprocessed by logistic scaling and histogram equalization. For both types of neural networks, the preprocessing step significantly improved classification compared to nonstandardized data. Classification accuracy was measured as prediction mean square error and Matthews correlation coefficient in the case of supervised learning, and quantization error in the case of unsupervised learning. The results demonstrate that appropriate data preprocessing is an essential step in solving classification tasks.

Algorithms↗
PubMedDate not supplied

Prognostic value of Laurén classification and c-erbB-2 oncogene overexpression in adenocarcinoma of the esophagus and gastroesophageal junction.

BACKGROUND: The prognostic value of the Laurén classification and of c-erbB-2 oncogene overexpression has been described for gastric cancer. The aim of this study was to investigate the clinical significance of these factors in adenocarcinoma of the esophagus and/or gastroesophageal junction (GEJ). METHODS: Forty-one adenocarcinomas of the esophagus and/or GEJ were reviewed for tumor stage, lymph node status, Laurén classification, and c-erbB-2 overexpression, as assessed by immunohistochemical analysis. RESULTS: According to the Laurén classification, tumors were classified as intestinal-, mixed-, or diffuse-type (54%, 32%, and 15%, respectively). Diffuse-type tumors were associated with a significantly worse prognosis than were intestinal-type tumors (P = .018; log-rank test). The prognostic value of the Laurén classification was independent of stage (P = .048; Cox regression model). Overexpression of c-erbB-2 was detected in 24% of the tumors and was present exclusively in intestinal-type tumors and in intestinal-type areas of mixed-type tumors. Ten of the 30 stage III/IV tumors (33%) were c-erbB-2-positive, whereas none of the 11 stage I/II tumors (0%) overexpressed the oncogene product (P = .04; Fisher exact test). The prognostic value of c-erbB-2 overexpression was not independent of stage (P = .7; Cox regression model). CONCLUSIONS: (1) The Laurén classification is an independent prognostic factor in adenocarcinoma of the esophagus and GEJ. (2) c-erbB-2 overexpression is limited to (areas of) intestinal-type tumors, indicating that intestinal- and diffuse-type tumors differ oncogenetically. (3) c-erbB-2 overexpression is associated with the stage of disease, indicating that it is a late event during tumor progression.

Adenocarcinoma↗
PubMed2006

Pattern classification and recognition of invertebrate functional groups using self-organizing neural networks.

Self-organizing neural networks can be used to mimic non-linear systems. The main objective of this study is to make pattern classification and recognition on sampling information using two self-organizing neural network models. Invertebrate functional groups sampled in the irrigated rice field were classified and recognized using one-dimensional self-organizing map and self-organizing competitive learning neural networks. Comparisons between neural network models, distance (similarity) measures, and number of neurons were conducted. The results showed that self-organizing map and self-organizing competitive learning neural network models were effective in pattern classification and recognition of sampling information. Overall the performance of one-dimensional self-organizing map neural network was better than self-organizing competitive learning neural network. The number of neurons could determine the number of classes in the classification. Different neural network models with various distance (similarity) measures yielded similar classifications. Some differences, dependent upon the specific network structure, would be found. The pattern of an unrecognized functional group was recognized with the self-organizing neural network. A relative consistent classification indicated that the following invertebrate functional groups, terrestrial blood sucker; terrestrial flyer; tourist (nonpredatory species with no known functional role other than as prey in ecosystem); gall former; collector (gather, deposit feeder); predator and parasitoid; leaf miner; idiobiont (acarine ectoparasitoid), were classified into the same group, and the following invertebrate functional groups, external plant feeder; terrestrial crawler, walker, jumper or hunter; neustonic (water surface) swimmer (semi-aquatic), were classified into another group. It was concluded that reliable conclusions could be drawn from comparisons of different neural network models that use different distance (similarity) measures. Results with the larger consistency will be more reliable.

Animals↗
PubMed2006

Mixture models and subpopulation classification: a pharmacokinetic simulation study and application to metoprolol CYP2D6 phenotype.

Mixture models are applied in population pharmacometrics to characterize underlying population distributions that are not adequately approximated by a single normal or lognormal distribution. In addition to obtaining individualized maximum a posteriori Bayesian post hoc parameter estimates, the subpopulation to which an individual was classified can be determined. However, the accuracy of the classification of subjects to subpopulations is not well studied. We investigated the impact of several factors on the accuracy of classification in mixture models applied to pharmacokinetics using a simulation strategy. The availability of actual subject data allowed us to evaluate mixture model classification in a potentially common application, namely, the classification of clearance into poor metabolizer (PM) or extensive metabolizer (EM) subgroups with the known phenotype status in subjects receiving metoprolol. The factors explored in the simulation study were the magnitude of difference between the clearances in two subpopulations, the between subject variability in clearance, the mixing-fraction, and the population sample size. Populations were simulated at various levels of the above factors and analyzed with a mixture model using NONMEM. The population pharmacokinetics of metoprolol were modeled with the EM/PM phenotype as a known covariate, and without the phenotype covariate using a mixture model. Within the range of scenarios studied, the proportion of subjects classified into the correct subpopulation was high. The simulation-estimation study suggests that a greater separation between two subpopulations, a smaller variability in the parameter distribution, a larger sample size, and a smaller size subpopulation tend to be associated with a greater accuracy of subpopulation classification when a mixture model is applied to pharmacokinetic data. In a population pharmacokinetic analysis of metoprolol, a drug that undergoes polymorphic metabolism, it was possible to correctly identify phenotype status using a mixture model.

Administration, Oral↗
PubMed2003

Classification of seizures and epilepsy.

The management of seizures and epilepsy begins with forming a differential diagnosis, making the diagnosis, and then classifying seizure type and epileptic syndrome. Classification guides treatment, including ancillary testing, management, prognosis, and if needed, selection of the appropriate antiepileptic drug (AED). Many AEDs are available, and certain seizure types or epilepsy syndromes respond to specific AEDs. The identification of the genetics, molecular basis, and pathophysiologic mechanisms of epilepsy has resulted from classification of specific epileptic syndromes. The classification system used by the International League Against Epilepsy is periodically revised. The proposed revision changes the classification emphasis from the anatomic origin of seizures (focal vs generalized) to seizure semiology (ie, the signs or clinical manifestations). Modified systems have been developed for specific circumstances (eg, neonatal seizures, infantile seizures, status epilepticus, and epilepsy surgery). This article reviews seizure and epilepsy classification, emphasizing new data.

Animals↗
PubMed2005

Classification of the vasculitides: are they clinically useful?

Several classification systems for the vasculitides have been developed over the second half of the past century. These classifications systems have been modified according to the advances made in the differentiation of these syndromes, particularly their histopathologic features (the vessel size involved) and their clinical features. Although these classifications have been widely used in the clinical setting for the diagnosis of these disorders, they were developed for research purposes. Given the common clinical and, sometimes, histopathologic features of the different vasculitides, a classification system that facilitates a diagnosis and the formulation of a therapeutic plan is still needed. The development and utilization of novel serum markers and new imaging modalities coupled with advances in the understanding of these disorders, may allow the development of a classification system for the vasculitides that will be of greater value in the clinical setting.

Clinical Medicine↗
PubMed1989

Classification of deaths after myocardial infarction as arrhythmic or nonarrhythmic (the Cardiac Arrhythmia Pilot Study).

The Cardiac Arrhythmia Pilot Study (CAPS) was a randomized, double-blind trial of antiarrhythmic drugs (encainide, flecainide, moricizine, imipramine and placebo) in 502 patients with at least 10 ventricular premature complexes/hour, 6 to 60 days after acute myocardial infarction. CAPS tested the feasibility of performing a larger study to determine if suppression of ventricular ectopic activity after acute myocardial infarction could improve survival. Patients in CAPS were followed for 1 year. All death or cardiac arrest events were evaluated by at least 2 investigators using a classification scheme that characterized the underlying mechanism as cardiac arrhythmic, cardiac nonarrhythmic or noncardiac. Forty-five patients (9%) died or had cardiac arrest during the 1-year follow-up, 29 (64%) within 1 hour from the onset of symptoms and 16 greater than 1 hour from the onset of symptoms. Twenty-three deaths (51%) were classified as arrhythmic, 19 (42%) as nonarrhythmic and 3 (7%) as noncardiac. Acute myocardial ischemia or infarction was associated with the death/cardiac arrest event in 16 patients (36%), 8 in the arrhythmic death group. Discrepancies in classification among reviewers were particularly common in patients with long-standing symptoms of congestive heart failure, in whom it was frequently difficult to identify the precise moment of the onset of symptoms in the death/cardiac arrest event. Using only the temporal relation of symptoms to categorize deaths or cardiac arrests, the mechanism of 12 (27%) of the 45 patients was in disagreement with the classification based on the Events Committee review. Classification of death as sudden or nonsudden is not equivalent to the classification of death as arrhythmic or nonarrhythmic.

Anti-Arrhythmia Agents↗
PubMed1986

Pathogenetic classifications of unstable angina as a guideline to individual patient management and prognosis.

Although it is widely recognized that unstable angina is a syndrome encompassing a variety of clinical and pathophysiologic entities, clinical trials and guidelines for management still consider patients with unstable angina as a single homogeneous group. When first recognized as a potentially threatening coronary syndrome, unstable angina was thought to be caused by extremely severe coronary obstructions that culminated in the syndrome of angina at rest, when coronary flow reserve is practically exhausted. It is now clear that the severity of coronary atherosclerosis in stable and unstable angina is, on the average, similar; and it appears that the features of "instability" are largely determined by dynamic obstructions superimposed on a widely variable fixed obstruction. Current clinical classifications, although based on purely descriptive symptoms, and angiographic classifications, based solely on coronary anatomy, independently identify subgroups of patients with unstable angina who have clearly distinct prognoses. The pathophysiologic classification proposed in this article considers both the severity of the underlying coronary fixed obstructions (as evidenced by the reduction of coronary flow reserve and by coronary anatomy) and the tendency for dynamic stenoses to develop (as evidenced by the pathophysiologic interpretation of symptoms and by the response to therapy). Since this classification combines elements of currently used clinical and angiographic classifications with a pathophysiologic interpretation, it can be applied easily in clinical practice and may provide more rational groupings of patients for both management and prognosis assessment.

Angina Pectoris↗
PubMed1987

Machine classification of infant sleep state using cardiorespiratory measures.

We examined the potential to classify sleep and waking state over the first 6 months of life in normal infants using only cardiac and respiratory measures. Twelve hour all-night polygraph recordings which included EEG, eye movement, whole body movement, facial muscle electromyographic, cardiac, and respiratory activity from 25 normal infants were collected at 1 week, and at 1, 2, 3, 4, and 6 months of age. Each minute of these recordings was classified into quiet sleep, waking, or rapid eye movement sleep by trained observers using EEG and somatic criteria. Respiratory rate and variability, heart rate and variability, and cardiac interbeat interval variation at respiratory and lower frequencies from 12 of the 25 infants were used as measures in discriminant analyses of sleep state for test on the 13 remaining infants. Using all 7 cardiac and respiratory measures, sleep states were classified with an accuracy approximating that attained by trained observers who had available all polygraph tracings (84.8% overall correct classification). Using only cardiac measures, the accuracy of classification decreased slightly, with an overall correct classification of 82.0%. Using only respiratory measures, the accuracy of classification diminished further, with an overall correct classification of 80.0%. Cardiac and respiratory measures provide quantifiable indications of sleep and waking states over the first 6 months of life in normal infants.

Computers↗
PubMed1996

Classification of pelvic ring injuries.

Advances in the operative stabilization of pelvic ring injuries, particularly by the development of special surgical techniques and implants, call for clear indications. These require the thorough analysis of the injury and its classification. Classification systems facilitate communication and the comparison of treatment concepts and results. Although a number of classification systems have been proposed, none of them has found universal acceptance. The following is a proposal for a comprehensive classification of pelvic ring injuries which, at the same time, accommodates the requirements of the AO/ASIF classification guidelines. The proposal is based primarily on radiographic morphology and secondarily on certain deductions made from it pertaining to the pathomechanics of the injury. To accommodate the extremely wide variety of possibilities, an open system was created by dividing the pelvic ring into anterior and posterior ring segments. Lesions of both segments can be freely combined for the definition of any given pelvic ring injury.

Fractures, Bone↗
PubMed1985

Problems in the classification of cause of death diagnoses affecting the reliability of mortality statistics for rheumatoid arthritis.

The uniformity of physicians' diagnostic language on death certificates involving rheumatoid arthritis (RA), and its influence on the medical classification and on the mortality statistics was investigated. The point of departure was a disagreement between physicians' reporting of RA on death certificates and the Swedish National Central Bureau of Statistics' (NCBS) registration of this condition, to the effect that the NCBS registered a threefold mortality increase for women and a twofold increase for men attributed to RA between 1971 and 1975, whereas the physicians had reported practically no change at all for women and a slight decrease for men between the years. It is investigated in the present study to what extent this increased NCBS registration of RA as the underlying cause of death could be explained by physicians' diagnoses for underlying non-RA conditions being disregarded in favour of RA due to classification problems with the former diagnoses. All Swedish RA death certificates for the years 1971 and 1975 were studied. A total of 1224 such death certificates were identified. Physicians' diagnostic language was found to be strongly individualistic. Out of the total of 1666 diagnostic expressions 1229 (74%) had been used only once. The corresponding proportions were 76% in 1971 and 73% in 1975. Thus, there was practically no change in the linguistic individualization between these years. The 1666 expressions could be coded by 287 ICD 8 codes. One hundred and thirty-nine different expressions had been used for rheumatoid arthritis (ICD 8 code 712.3). One hundred and fifty-six (13%) of the death certificates contained diagnostic expressions encumbered with one or more of four major kinds of classification problems: (1) Expression(s) without ICD 8 code (24 certificates); (2) Expression(s) with several codes, uncertainty about which to select (45 certificates); (3) Expression(s) with several codes, one is preferable according to the ICD (39 certificates); and (4) Expression(s) which can be coded both by one specific code and by several codes (60 certificates). In one third (35%) of these cases the expression used referred to an underlying cause of death. The alternative interpretations of all these expressions differed in most cases on a three-digit level and in some cases on chapter level in the classification. Clarification of ambiguous expressions were solicited by the NCBS in only one case in 1971 and one in 1975. The NCBS' increased registration RA as the underlying cause of death between 1971 and 1975 could not be explained by problems of classification.

Arthritis, Rheumatoid↗
PubMed1985

The classification of children's knowledge: development on the balance-scale and inclined-plane tasks.

R.S. Siegler (1981, Monographs of the Society for Research in Child Development, 46 C2, Serial No. 189) has shown that performance on several Piagetian tasks is governed by similar rule structures. The purpose of the first study was to extend his analysis to the inclined-plane task, replicate his original observations about development on the balance-scale task, and determine the consistency in children's rule usage across tasks. We found that Siegler's (1981) binary decision representations adequately characterized development on these tasks, and there was fair correspondence of rule classifications across tasks. An alternative classification procedure, used to diagnose the rules of children who failed our original classification criteria, showed that most of these children's performance patterns were very similar to Siegler's rule patterns. In the second experiment, we improved the diagnosticity of our rule-assessment protocol in light of F. Wilkening and N. H. Anderson's (1982, Psychological Bulletin, 92, 215-237) criticisms, and observed that many Rule III children's predictions were associated with those of integration rules on both tasks. Despite these methodological improvements, many children, especially 5- to 7-year-olds, evidenced use of centration and lexicographic strategies, suggesting that these classifications are not simply an artifact of problem sampling. Some of the problems associated with the classification of children's knowledge are discussed.

Child↗
PubMed1986

Proposals for the classification and nomenclature of functional receptors for 5-hydroxytryptamine.

As a result of controversy in the literature regarding the classification and nomenclature of functional receptors for 5-hydroxytryptamine (5-HT), a framework for classification is proposed. The formulation of these proposals has only been made possible by the recent advent of new drug tools. It is considered that there are three main types of 5-HT receptor, two of which have been well characterised pharmacologically, using selective antagonists, and which it is proposed to name 5-HT2 and 5-HT3. These two groups broadly encompass the "D" and "M" receptors, respectively, which Gaddum identified in the guinea-pig ileum (Gaddum and Picarelli, 1957). The 5-HT2 receptor, which mediates a variety of actions of 5-HT, has been definitively shown to correlate with the 5-HT2 binding site in the brain. No binding studies in brain tissue have yet been published with radiolabelled ligands specific for 5-HT3 receptors. A number of other actions of 5-HT appear to be mediated via receptors distinct from 5-HT2 or 5-HT3 receptors. Since selective antagonists are not yet available, these receptors cannot be definitively characterised, although in many cases they do have some similarities with 5-HT1 binding sites, which are a heterogeneous entity. Criteria are proposed for tentatively classifying these receptors as "5-HT1-like" (Table 1). Definitive characterisation of these receptors will await the identification of specific antagonists. This classification of 5-HT receptors into three main groups (Table 1) is based largely, but not exclusively, on data from studies in isolated peripheral tissues where definitive classification is possible. However, it is believed that this working classification will be relevant to functional responses to 5-HT in the central nervous system.

Animals↗