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PubMed1989

The P-A-I-N MMPI classification system: a critical review.

The Costello et al. (Pain, 30 (1987) 199-209) literature-based MMPI clustering algorithm was compared to a standard clustering procedure of chronic pain patients' MMPI profiles. Results indicated that the Costello algorithm was too restrictive, failing to classify 69% of the MMPI profiles of the local sample. It was suggested that it may be premature to adopt a literature based clustering method until the validity of empirically derived clusters has been more thoroughly determined. The utility of a given set of clusters may best be determined by using locally derived clusters to predict treatment response. Once the predictive validity of the local clusters has been demonstrated, the Costello approach may prove more useful.

Adolescent↗
PubMed2026

Identifying JAK2 and ANXA5 as Key Genes Linking Obstructive Sleep Apnea and Oxidative Stress via Machine Learning and Multilayer Transcriptomic Integration With Functional Validation.

Obstructive sleep apnea (OSA) is a common and severe sleep disorder closely associated with oxidative stress (OS). This study aims to identify and validate potential OS-related genes associated with OSA through bioinformatics methods. We successfully identified OS-related differentially expressed genes (OS-DEGs) by combining the limma test, weighted correlation network analysis (WGCNA), and OS-related genes from the GeneCards database. Key genes and potential biological roles were further identified using Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG), enrichment analysis, protein-protein interaction (PPI) network analysis, Lasso regression analysis, random forest algorithm, and support vector machine recursive feature elimination (SVM-RFE) method. Evaluate and validate the accuracy of key genes through receiver operating characteristic (ROC) curve analysis. The human single-cell RNA sequencing (scRNA-seq) dataset is used for cell classification annotation, analysis of key gene single-cell expression profiles, and virtual gene knockout experiments based on the scTenifoldKnk algorithm. Integrating scRNA-seq sequencing, pseudotime trajectory inference, cell-cell communication analysis, and bulk immune infiltration deconvolution reveals monocyte subtype remodeling in OSA. Finally, the expression levels of key genes in clinical samples were validated using real-time quantitative PCR (RT-qPCR) and Western blotting. A total of 57 common DEGs, indicating significant enrichment in OS, inflammation, and tumor pathways, particularly prominent in the immunometabolism pathway. By integrating DEGs, WGCNA, PPI results, and machine learning methods, key genes Janus kinase 2 (JAK2) and ANXA5 were screened out. JAK2 was significantly upregulated under disease conditions, while ANXA5 was significantly downregulated. ROC curve exhibited high accuracy (area under the curve [AUC] > 0.85). Human scRNA-seq analysis revealed that key genes were predominantly highly expressed in monocytes. Virtual knockout experiments demonstrated that these key genes play a crucial role in regulating immune responses and inflammatory reactions. PPI networks and enrichment analysis verified that downstream genes S100P, ALOX5AP, PROK2, and PADI4 may collaboratively participate in immune response and inflammation regulation. Finally, clinical sample experiment further validated the results of bioinformatics analysis. This study provides new research insights for the diagnosis, mechanism research, and treatment development of OSA in the future by integrating multilayer transcriptomic and machine learning techniques.

Humans↗
PubMed1989

[Description of a system for automatic analysis of ambulatory electrocardiography using a microcomputer].

An automatic ambulatory electrocardiogram analyzer was developed using a self-powered fast reader of FM recorded cassettes and a "general purpose" microcomputer with 640 Kbytes of RAM and 20 Mbytes of mass memory on hard-disk. Original algorithms were developed for analog to digital conversion, data storage on hard-disk, QRS detection and classification and rhythm analysis. Reliability of the system was evaluated, when appropriate, using standard databases. The relevant features of our analyzer include a favourable cost/benefit ratio, powerful interactive facilities and the typical flexibility of the non dedicated hardware.

Algorithms↗
PubMed1991

The use of modified constellation graph method for computer-aided classification of congenital heart diseases.

This paper describes a new method of data reduction and classification in a multidimensional symptom space for diagnostic aid of congenital heart diseases. The algorithm developed here is to reduce interactively a multidimensional symptom space to sectorial regions representing each disease in a semicircle using the modified constellation graph method. This method enables us to classify patients using the angle in the semicircle as a single classifying parameter with an accuracy of about 90%, that is, with little overlapping between disease sectors. Comparing this method with conventional factor analysis, we have found the former far more effective than the latter for disease region separation.

Algorithms↗
PubMed1992

Selection of a representative set of structures from Brookhaven Protein Data Bank.

Reliable structural and statistical analyses of three dimensional protein structures should be based on unbiased data. The Protein Data Bank is highly redundant, containing several entries for identical or very similar sequences. A technique was developed for clustering the known structures based on their sequences and contents of alpha- and beta-structures. First, sequences were aligned pairwise. A representative sample of sequences was then obtained by grouping similar sequences together, and selecting a typical representative from each group. The similarity significance threshold needed in the clustering method was found by analyzing similarities of random sequences. Because three dimensional structures for proteins of same structural class are generally more conserved than their sequences, the proteins were clustered also according to their contents of secondary structural elements. The results of these clusterings indicate conservation of alpha- and beta-structures even when sequence similarity is relatively low. An unbiased sample of 103 high resolution structures, representing a wide variety of proteins, was chosen based on the suggestions made by the clustering algorithm. The proteins were divided into structural classes according to their contents and ratios of secondary structural elements. Previous classifications have suffered from subjective view of secondary structures, whereas here the classification was based on backbone geometry. The concise view lead to reclassification of some structures. The representative set of structures facilitates unbiased analyses of relationships between protein sequence, function, and structure as well as of structural characteristics.

Algorithms↗
PubMed1986

Syntactic analysis of the epileptic electroencephalogram.

A full-scale scheme of the multi-level syntactic analysis of the epileptic EEG is presented and discussed in detail. An exhaustive description of basic procedures necessary to obtain a meaningful description of any set of epileptic EEG recordings is given; these procedures include algorithms for extraction of various elementary peaks from the EEG signal, for segmentation of the recording, for classification of the segments found into distinct groups of characteristic patterns and, finally, for calculation of the Levenshtein distance between the individual recordings, each recording regarded as a string of symbols taken to represent different classes of patterns. An example of global analysis in terms of such a distance, performed on a typical set of epileptic EEG recordings, is supplied to prove the feasibility of the scheme proposed.

Algorithms↗
PubMed1986

Classifying function for health outcome and quality-of-life evaluation. Self- versus interviewer modes.

Validity assessment and the underreporting of dysfunction have been major problems in health-related quality-of-life measurement, including collecting data for analysis by the General Health Policy Model, using the Quality of Well-being scale (QWB). This analysis compares the results of self- versus interviewer modes of measurement and short, direct-answer questions versus probing algorithms in the QWB. The comparisons are made in terms of 1) correlations; 2) aggregate frequencies; 3) individual subject classifications; and 4) the actual state, established using evidence from multiple sources. Despite extremely high correlations between QWB scores from the two modes (greater than 0.98), the lowest interviewer mode sensitivity (0.86) and predictive value dysfunctional (0.91) were substantially superior to the highest self-classification characteristics (0.66 and 0.73). In the populations studied, specificities and predictive values functional were equivalent (greater than 0.94) for the two modes. The probe pattern of the interviewer mode was also less susceptible to false reports of dysfunction. These results are consistent with the underreporting of dysfunction noted by several major investigations of health status measurement. The authors conclude that interviewer-administered instruments using question algorithms are necessary if health-related quality of life is to be measured with sufficient reliability and validity to evaluate major clinical trials and follow-up studies.

Adult↗
PubMed1991

Classification of plasma cortisol patterns in normal subjects and in Cushing's syndrome.

The 24-h pattern of half-hourly sampled plasma cortisol in normal human subjects shows a 24-h (circadian) period, which may be variably distorted in patients who suffer from autonomous hypercortisolism (Cushing's syndrome). We have developed a pattern recognition system for computer classification of cortisol time series into the normal class and subclasses of Cushing's syndrome with different etiology ("pituitary" designating pituitary tumor, "adrenal" designating adrenal tumor, and "ectopic" designating tumor elsewhere). Discriminatory features were extracted from Fourier analysis and Karhunen-Loeve expansion coefficients of cortisol time series. Decision functions were trained by the LMSE algorithm and tested by the jack-knife test procedure on a data-base of 90 normal and patient patterns. The classification accuracy for normal, "pituitary," "adrenal," and "ectopic" classes was 100, 98.1, 98.3, and 100%, respectively. Hence this pattern recognition system may be useful as an aid in the differential diagnosis of Cushing's syndrome.

Algorithms↗
PubMed1990

Objective assessment of image quality: effects of quantum noise and object variability.

A number of task-specific approaches to the assessment of image quality are treated. Both estimation and classification tasks are considered, but only linear estimators or classifiers are permitted. Performance on these tasks is limited by both quantum noise and object variability, and the effects of postprocessing or image-reconstruction algorithms are explicitly included. The results are expressed as signal-to-noise ratios (SNR's). The interrelationships among these SNR's are considered, and an SNR for a classification task is expressed as the SNR for a related estimation task times four factors. These factors show the effects of signal size and contrast, conspicuity of the signal, bias in the estimation task, and noise correlation. Ways of choosing and calculating appropriate SNR's for system evaluation and optimization are also discussed.

Algorithms↗
PubMedDate not supplied

Image analysis methods for solitary pulmonary nodule characterization by computed tomography.

Computer software was designed for classifying solitary pulmonary nodules (SPNs) into benign and malignant from their CT images, using image analysis methods. The system made use of three features, computed from the CT density matrix of the SPN, and a class-discriminating algorithm. System evaluation was performed on 51 histologically confirmed SPNs of indeterminate CT diagnosis. Overall classification accuracy in distinguishing benign and malignant SPNs was 90.2%, while 83.3% of the benign and 93.9% of the malignant SPNs were correctly classified. The proposed system may be of value to the radiologist in assessing the probability of malignancy in patients with a solitary pulmonary nodule.

Adult↗
PubMed1985

Toward the development of operational criteria of differentiated mental states.

The purpose of this paper is to discuss possibilities for developing operational criteria in psychopathological states and to identify the parameters that differentiate psychotic patients. Statistical analysis was performed in the first step with the aid of factor analysis with extraction of syndromatic characteristics of so-called psychopathological basis syndromes. By cluster analysis in the second step we found out more approaches to a differentiated definition of psychotic states. The classification of individuals into 'natural' and not preestablished groups enabled the construction of descriptive psychopathological algorithms to determine ICD-9 diagnosis within the limitations of descriptive psychiatry.

Affective Disorders, Psychotic↗
PubMed1991

Periprosthetic fractures of the femur after total knee arthroplasty. A literature review and treatment algorithm.

Supracondylar femur fractures after total knee arthroplasty can significantly alter the quality of knee arthroplasties and provide a challenging problem for the treating surgeon. A review of the literature and an approach to the treatment of these periprosthetic fractures is presented. The predisposing factors, mechanisms of injuries, and characteristics of the fractures are identified. A classification system is proposed based on a modified Neer grading system, the degree of comminution, and the location and character of the fracture. A treatment algorithm is developed and based on acceptable alignments of less than 5 mm translations, angulations less than 5 degrees-10 degrees, minimal rotation, less than 1 cm of femoral shortening, and proper tibiofemoral prosthetic joint alignment.

Algorithms↗
PubMed1985

Computerized EEG pattern classification by adaptive segmentation and probability-density-function classification. Description of the method.

A phenomenological model for the representation of clinical EEGs is proposed. It assumes each individual record to consist of a few repetitive patterns which are described sufficiently by their power spectra. An algorithm for automatic EEG evaluation is described. It consists of two steps, a segmentation process which isolates the elementary patterns, and a clustering procedure which groups similar patterns with each other. Results are represented in graphical form. Diagnostic classification is not attempted. An appendix highlights the advantages of autoregressive modelling for EEG spectral analysis and, in particular, the estimation of the power contained in the various "rhythms".

Biometry↗
PubMedDate not supplied

Computerized interactive morphometry as an aid in the diagnosis of pleural effusions.

A morphometric study of cytologic preparations from patients with benign and malignant (mesothelioma and carcinoma) pleural effusions is reported. The routine cytologic smears from these specimens were studied with a new system of video-based computerized interactive morphometry (CIM) that allows the measurements of real-time images of cell profiles by the simple procedure of touching the two extreme points of a diameter of interest on a touch-sensitive screen. For each cell, the nuclear profile diameter (NPD) and the cytoplasmic profile diameter (CPD) are measured and categorized into classes with 2-microns intervals; the NPD/CPD ratio is also calculated. The mean NPD is calculated for the specimen after measurement of 100 cells. The data were interpreted by two independent methods: a statistical method of discriminant analysis that classifies the lesions as benign, carcinoma or mesothelioma and provides a probability statement of membership in a particular diagnostic class and an ad-hoc algorithm that categorizes the effusions as benign or malignant based on hierarchic analysis. A data base derived from study of the first 24 cases was constructed and utilized for the test classification of the second 24 cases, which were treated as specimens of unknown diagnosis. The discriminant analysis correctly classified 21 of the 24 test cases into their proper diagnostic groups. The algorithm for a computer-generated pathologic diagnosis correctly identified 47 of the 48 cases as benign or malignant. The technical advantages of video-based CIM over the existing morphometric methods are discussed.

Carcinoma↗
PubMed1985

[Automatic detection of grouped patterns in EEG].

The detection and classification of grouped (so called paroxysmal) activity and of artefacts of similar appearance is a necessary part of the automated description of clinical EEGs. An algorithm for this task is presented. It is based on short-time spectra and on parameters extracted from them. The rate of agreement with the visual assessment is nearly the same as that between well trained EEGers. This is true for the classification and to nearly the same degree for the detection. Nevertheless these patterns must be grouped and validated if the method is to be used in practice. A modification useful for a fast analysis combined with the quantitative description of the background activity is discussed.

Brain Diseases↗
PubMed1992

Split cord malformation: Part II: Clinical syndrome.

Thirty-nine patients with split cord malformations (SCM) were studied in detail with respect to their clinical, radiographic, and surgical findings as well as their outcome data. Eight patients were adults and 31 patients were children. According to the classification endorsed by Part I of the SCM study, 19 patients had Type I SCM (6 adults and 13 children), 18 patients had Type II SCM (2 adults and 16 children), and 2 patients had composite SCM with both lesion types situated in tandem. Six SCMs were cervical, 2 were thoracic, and 31 were in the lumbar region. All 8 adults had pain and progressive sensorimotor deficits at diagnosis. Only 16 of the 31 children had symptoms, and among these, 14 had progressive sensorimotor deficits, but only 6 had pain. The difference in the clinical picture between adults and children is similar to that described in the tethered cord syndrome, except for left-right functional discrepancy, which was prominent in 8 children with SCM but rarely seen in tethered cord syndrome due to other causes. Cutaneous manifestations of either occult or open dysraphic states were present in all but 3 patients; hypertrichosis was by far the best predictor of an underlying SCM, being found in 56% in the series. Neurological deterioration in SCM was independent of the lesion type: the Type I:Type II ratio for symptomatic progression was 13:11. It was also independent of the location of the lesion: 67% of patients with cervical SCMs had symptomatic progression versus 64% of patients with thoracolumbar lesions. High-resolution, thin cut, axial computed tomographic myelography using bone algorithms was more sensitive than magnetic resonance imaging in defining the anatomical details of the SCM. Radiographic classifications of the SCM, using the nature of the median septum and the number of dural tubes as criteria, was always possible without ambiguity. However, whereas every Type I bone septum was identified preoperatively, only 5 Type II fibrous septa were revealed by preoperative imaging, even though a fibrous septum and/or other fibroneurovascular bands were found tethering the hemicords in every Type II case at surgery. Complete imaging studies also showed that all lumbar SCMs had low-lying coni and at least one additional tethering lesion besides the split cords, whereas only 1 of 7 cervical and high thoracic SCMs had a low conus and a second tethering lesion. The surgical goal for SCM was release of the tethered hemicords by eliminating the bone spurs, dural sleeves, fibrous septa, or any fibroneurovascular bands (myelomeningoceles manqué) that might be transfixing the split cord. Type I cases were technically more difficult and had a slightly higher surgical morbidity than Type II cases, especially if an oblique bone septum had asymmetrically divided the cord into one larger hemicord and one smaller, hence, very delicate, hemicord.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗