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Results for “Multiple Classification Analysis”

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PubMed2005

Impact of age on both BIS values and EEG bispectrum during anaesthesia with sevoflurane in children.

BACKGROUND: The aim of this study was to evaluate the potential relationship between age, BIS (Aspect), and the EEG bispectrum during anaesthesia with sevoflurane. METHODS: BIS and raw EEG were recorded at a steady state of 1 MAC in 100 children, and during a decrease from 2 to 0.5 MAC in a sub-group of 29 children. The bispectrum of the EEG was estimated using MATLAB software. For analysis, the bispectrum was divided into 36 frequencies of coupling (P(i))--the MatBis. A multiple correspondence analysis (MCA) was used to establish an underlying structure of the pattern of each individual's MatBis at 1 MAC. Clustering of children into homogeneous groups was conducted by a hierarchical ascending classification (HAC). The level of statistical significance was set at 0.05. RESULTS: At 1 MAC, the BIS values for all children ranged from 20 to 74 (median 40). Projection of both age and BIS value recorded at 1 MAC onto the structured model of the MCA showed them to be distributed along the same axis, demonstrating that the different values of BIS obtained in younger or older children are mainly dependent on their MatBis. At 1 MAC, six homogeneous groups of children were obtained through the HAC. Groups 5 (30 months; range 23-49) and 6 (18 months; range 6-180) were the younger children and Group 1 (97 months; range 46-162) the older. Groups 5 and 6 had the highest median values of BIS (54; range 50-59) (55; range 26-74) and Group 1 the lowest values (29; range 22-37). CONCLUSION: The EEG bispectrum, as well as the BIS appeared to be strongly related to the age of children at 1 MAC sevoflurane.

Adolescent↗

PubMedDate not supplied

Spiritual care activities of nurses using Nursing Interventions Classification (NIC) labels.

PURPOSE: To describe the spiritual care activities of nurses as subsequently identified in the Nursing Interventions Classification (NIC) labels. METHODS: Data were taken from a larger study that used a multiple triangulation research design to describe spiritual perspectives, interventions, and attitudes of 1,000 Sigma Theta Tau International members. Data analysis included descriptive and multivariate statistics for quantitative items, and content analysis for responses to questions. FINDINGS: 97 respondents reported providing 32 spiritual care activities. Ten NIC labels actually mapped the nurses' spiritual care activities. CONCLUSIONS: Spiritual care activities involve a broad spectrum of interventions that may be unique to each patient. The 32 spiritual care activities described by the nurses provide new knowledge regarding core spiritual care activities. The use of NIC labels can facilitate documentation of spiritual care activities in diverse practice settings. PRACTICE IMPLICATIONS: This study supports greater specificity in describing spiritual care interventions to a level that allows replication and advancement of knowledge.

Adult↗

PubMed1996

Caliber estimation from cranial entrance defect measurements.

Caliber estimation from entrance defects has long been rejected by forensic scientists. This appears to be a consequence of soft tissue perspective of forensic pathologists. This study examined the relation between caliber and cranial entrance defects and maximum cranial thickness. The calibers considered in this inquiry were .22, .25, .32, and .38. The sample consisted of 73 specimens obtained at autopsy (thirty-seven of .22 caliber, five of .25, six of .32, and twenty-five of .38). To test the strength of the relation between caliber, minimum diameter, and maximum thickness Pearson correlation coefficients were conducted. The strongest relationship was observed between caliber and minimum diameter. A relationship between minimum diameter and maximum thickness was also observed. To test the null hypothesis that the mean minimum diameter is not significantly different between calibers an analysis of variance procedure was performed. The ANOVA yielded a strong relationship between dependent variable minimum diameter and caliber. Multiple regression analysis measuring the association between minimum diameter, caliber, and maximum thickness was also conducted. The Pr > F .0001 suggests that the overall model is significant. Discriminant functions and canonical variables were obtained. Classification was first performed by using two values small and large calibers. The large caliber group consisted of .38, while the small caliber group included .22, .25, and .32. The correct classification rate using crossvalidation for large caliber is 86.96%, and 93.33% for the group small caliber. A narrower classification was also performed by using three values, .23 caliber (.22 and .25 calibers grouped), .32, and .38 as the criterion variable groups also using minimum diameter and maximum thickness as predictors. The correct classification rate using crossvalidation is 82.02% for .23 caliber, 73.94% for .38 caliber, and 16.67% for .32 caliber defects. The discriminant functions can be used with appropriate caution to classify observations into groups defined by caliber using minimum diameter and maximum thickness as the predictors. Caution is suggested when attempting to estimate caliber from defects that are not produced from the perpendicular entrance of a bullet.

Analysis of Variance↗

PubMed2003

Single- versus multiple-fraction radiotherapy in patients with painful bone metastases: cost-utility analysis based on a randomized trial.

BACKGROUND: Radiotherapy is an effective palliative treatment for cancer patients with painful bone metastases. Although single- and multiple-fraction radiotherapy are thought to provide equal palliation, which treatment schedule provides better value for the money is unknown. We compared quality-adjusted life expectancy (the overall valuation of the health of the patients) and societal costs for patients receiving either single- or multiple-fraction radiotherapy. METHODS: A societal cost-utility analysis was performed on a Dutch randomized, controlled trial of 1157 patients with painful bone metastases that compared pain responses and quality of life from a single-fraction treatment schedule of 8 Gy with a treatment schedule of six fractions of 4 Gy each. The societal values of life expectancies were assessed with the EuroQol classification system (EQ-5D) questionnaire. A subset of 166 patients also answered additional questionnaires to estimate nonradiotherapy and nonmedical costs. Statistical tests were two-sided. RESULTS: Comparing the single- and multiple-fraction radiotherapy schedules, no differences were found in life expectancy (43.0 versus 40.4 weeks, P =.20) or quality-adjusted life expectancy (17.7 versus 16.0 weeks, P =.21). The estimated cost of radiotherapy, including retreatments and nonmedical costs, was statistically significantly lower for the single-fraction schedule than for the multiple-fraction schedule ($2438 versus $3311, difference = $873, 95% confidence interval [CI] on the difference = $449 to $1297; P<.001). The estimated difference in total societal costs was larger, also in favor of the single-fraction schedule, but it was not statistically significant ($4700 versus $6453, difference = $1753, 95% CI on the difference = -$99 to $3604; P =.06). For willingness-to-pay between $5000 and $40 000 per quality-adjusted life year, the single-fraction schedule was statistically significantly more cost-effective than the multiple-fraction schedule (P< or =.05). CONCLUSIONS: Compared with multiple-fraction radiotherapy, single-fraction radiotherapy provides equal palliation and quality of life and has lower medical and societal costs, at least in The Netherlands. Therefore, single-fraction radiotherapy should be considered as the palliative treatment of choice for cancer patients with painful bone metastases.

Adult↗

PubMed1998

MEG covariance difference analysis: a method to extract target source activities by using task and control measurements.

A method is proposed for extracting target dipolesource activities from two sets of evoked magnetoencephalographic (MEG) data, one measured using task stimuli and the other using control stimuli. The difference matrix between the two covariance matrices obtained from these two measurements is calculated, and a procedure similar to the MEG-multiple signal classification (MUSIC) algorithm is applied to this difference matrix to extract the target dipole-source configuration. This configuration corresponds to the source-configuration difference between the two measurements. Computer simulation verified the validity of the proposed method. The method was applied to actual evoked-field data obtained from simulated task-and-control experiments. In these measurements, a combination of auditory and somatosensory stimuli was used as the task stimulus and the somatosensory stimulus alone was used as the control stimulus. The proposed covariance difference analysis successfully extracted the target auditory source and eliminated the disturbance from the somatosensory sources.

Algorithms↗

PubMed1997

Spinal and cutaneous schwannomatosis is a variant form of type 2 neurofibromatosis: a clinical and molecular study.

OBJECTIVE: To delineate the clinical phenotype, molecular basis, and implications for screening in patients and families with multiple schwannomas not generally involving the cranium. METHODS: As part of a United Kingdom clinical and genetic study of type 2 neurofibromatosis (NF2) patients and families with multiple schwannomas who do not fulfil diagnostic criteria for NF2 have been identified. The clinical phenotype was studied in the extended families and molecular analysis was carried out at the NF2 gene locus on chromosome 22. RESULTS: Patterns of inheritance in five families with schwannomatosis are consistent with inheritance of an autosomal dominant gene. The consistency of phenotype, with relative sparing of the cranium, is constant in these families. However, families which initially seem to be indicative of schwannomatosis may develop into classic NF2 as shown by a sixth family. Many of the tumours found in these families were referred to as "neurofibroma" when they were clearly schwannomas. This difference in classification has major implications for the relative risk of each particular type of neurofibromatosis and neuropathological review may be important in some cases. Genetic linkage analysis in the two largest families is entirely consistent with primary involvement of the NF2 gene. CONCLUSIONS: Variant forms of neurofibromatosis have presented a dilemma in classification and determination of recurrence risks in families. Previous reports have suggested that schwannomatosis is a sporadic non-hereditary condition. Patients with multiple schwannomas are likely to have a variant form of NF2 and up to a 50% risk of passing on a gene predisposing to multiple schwannoma.

Adolescent↗

PubMed1993

Three-marker phenotypic analysis of lymphocytes based on two-color immunofluorescence using a multinomial model for flow cytometric counts and maximum likelihood estimation.

The simultaneous flow cytometric study of multiple (> or = 3) markers on individual cells is restricted by technical reasons, e.g., the type of flow cytometer, and the availability of (monoclonal) antibodies (mAb) conjugated with the appropriate fluorochromes. However, a n-way classification (n > or = 3) may be derived from multiple 2-way classifications. The 2-way classifications are obtained by the use of only two fluorochromes, but each fluorochrome may be used for the simultaneous labelling of 2 or more mAb. We present a formal statistical model, based on an underlying multinomial distribution for the observed quadrant counts, by which data from such multiple 2-way classifications can be analyzed. The model is restricted to 3-marker phenotypic analyses, but can be extended to n-way classifications (n > 3). Maximum likelihood estimates are obtained by the application of the EM algorithm. The model was tested on 20 samples of peripheral blood mononuclear cells to study the coexpression of CD45RA, CD45RO, and Leu 8 by lymphocyte subsets defined by the CD56 (MHC-unrestricted cytotoxic cells) and CD3 (T cells) markers. Application of the model gave an excellent fit in all but one cases. In addition, the model reduced the effect of inter-assay variation on the estimates and it provided an analysis of consistency over the data, which allows the detection of outliers due to staining errors.

Cell Adhesion Molecules↗

PubMed2006

Simulating discrete and rhythmic multi-joint human arm movements by optimization of nonlinear performance indices.

An optimization approach applied to mechanical linkage models is used to simulate human arm movements. Predicted arm trajectories are the result of minimizing a nonlinear performance index that depends on kinematic or dynamic variables of the movement. A robust optimization algorithm is presented that computes trajectories which satisfy the necessary conditions with high accuracy. It is especially adapted to the analysis of discrete and rhythmic movements. The optimization problem is solved by parameterizing each generalized coordinate (e.g., joint angular displacement) in terms of Jacobi polynomials and Fourier series, depending on whether discrete or rhythmic movements are considered, combined with a multiple shooting algorithm. The parameterization of coordinates has two advantages. First, it provides an initial guess for the multiple shooting algorithm which solves the optimization problem with high accuracy. Second, it leads to a low dimensional representation of discrete and rhythmic movements in terms of expansion coefficients. The selection of a suitable feature space is an important prerequisite for comparison, recognition and classification of movements. In addition, the separate computational analysis of discrete and rhythmic movements is motivated by their distinct neurophysiological realizations in the cortex. By investigating different performance indices subject to different boundary conditions, the approach can be used to examine possible strategies that humans adopt in selecting specific arm motions for the performance of different tasks in a plane and in three-dimensional space.

Algorithms↗

PubMed2004

Bcl-2 protein expression is the strongest independent prognostic factor of survival in primary cutaneous large B-cell lymphomas.

Bcl-2 protein expression has been associated with poor prognosis in patients with noncutaneous diffuse large B-cell lymphomas. In primary cutaneous large B-cell lymphomas, the location on the leg, the round-cell morphology defined as the predominance of centroblasts and immunoblasts over large centrocytes, and multiple skin lesions were identified as adverse prognostic factors. The prognostic value of bcl-2 protein expression has not been studied in large series of patients. We evaluated 80 primary cutaneous large B-cell lymphomas collected by the French Study Group on Cutaneous Lymphomas. The prognostic value of age, sex, number of lesions, cutaneous extent, location, serum lactate dehydrogenase (LDH) level, B symptoms, morphology, and bcl-2 protein expression was studied. The overall 5-year specific survival rate was 65%. In univariate analysis, advanced age, multiple skin lesions (n = 48), location on the leg (n = 25), round-cell morphology (n = 32), and bcl-2 expression (n = 39) were significantly related to death from lymphoma. In multivariate analysis, bcl-2 expression (P =.0003), multiple skin lesions (P =.004), and age remained independent prognostic factors. The 5-year specific survival rates in bcl-2-positive and bcl-2-negative patients were 41% and 89%, respectively (P <.0001). A new prognostic classification of primary cutaneous B-cell lymphoma should be based primarily on bcl-2 protein expression rather than the location of skin lesions.

Adult↗

PubMed1985

[Multiple sclerosis and the electroencephalogram (computer EEG studies)].

A computerized analysis of EEg-records from 96 multiple sclerosis (MS) patients yielded about twice as many abnormal results (79%) in comparison to the usual visual EEG-evaluation (39%). The statistically significant (p less than 0.05) increase in slow frequencies in addition to beta frequencies to the cost of alpha, but especially the reduction in total percentage of alpha contribution to overall EEG-power discriminated most efficiently between MS-patients and our normal population. Thus, alpha index alone allowed for 87% correct classification of the normal population, and 73% of patients with normal visual EEG-records were correctly classified as belonging to the MS-population. Extending the patient group to include pathological visual EEG-records as well, the corresponding figures were 95% and 89%, respectively. The computerized EEG-analysis was thus clearly superior to the usual visual inspection.

Adult↗

PubMed1999

Foundations for effective strategies to control sexually transmitted infections: voices from rural Kenya.

Achieving maximal benefit from clinic-based, sexually transmitted infection (STI) control strategies requires that persons seek treatment at public clinics. Community-based, ethnographic research methods were used to examine patterns of health-seeking behavior for sexually transmitted infections in western Kenya. Illness narratives of sexually transmitted infections provided the basis for an analysis of sequential steps in health-seeking behavior, namely recognition, classification, overcoming stigma, identification of treatment options and selection of a course of therapy. A variety of terms were used to identify STI, including multiple terms referring to "women's disease". The stigma associated with STI, reflected in the terminology, was based on a set of beliefs on the causes, contagiousness and sequelae of STI, and resulted in delays in seeking treatment. Five commonly used treatment options were identified, with multiple sources of care often used concurrently. The desire for privacy, cost and belief in the efficacy of traditional medicines strongly influenced health-seeking behaviour. A belief that sexually transmitted infections must be transmitted in order to achieve cure was professed by several respondents and promoted by a traditional healer. Implications for STI control strategies are derived, including the development of educational messages and the design of clinics.

Acquired Immunodeficiency Syndrome↗

PubMed2000

Prediction of recovery of continuous memory after traumatic brain injury.

OBJECTIVE: To evaluate the ability of measures of initial severity, tests of attention, and demographic characteristics to predict recovery of continuous memory for words over a 24-hour period in patients with acute traumatic brain injury. METHODS: Recovery of continuous memory was assessed prospectively in 94 patients with nonpenetrating traumatic brain injury. A classification and regression tree analysis identified a hierarchical subset of variables that may be used as a simple guideline for predicting recovery of continuous memory. Weibull regression models evaluated and compared the predictive ability of multiple variables. RESULTS: Four groups of patients were identified based on measures of severity of injury and demographic characteristics. These four groups had recovery profiles that were more precise than could be obtained by using the Glasgow Coma Scale alone: mild, about 1 week to recovery of continuous memory; moderate, 1 to 4 weeks; severe, 2 to 6 weeks; and extremely severe, 4 to 8 weeks. Regression analysis confirmed that measures of capacity (inherent resources such as indicated by age) and compromise (general functional brain state measured neuropsychologically) improved prediction over models based only on injury severity measures, such as the Glasgow Coma Scale. CONCLUSIONS: Approaches to predicting recovery of continuous memory in the acute period after traumatic brain injury that take into account multiple measures provide a more sensitive predictive index.

Adult↗

PubMed2000

Study on acid-base disturbance in patients with post-traumatic multiple organ dysfunction syndrome.

OBJECTIVE: To investigate the classification and incidence of acid-base disturbance (ABD) in the patients with post-traumatic multiple organ dysfunction syndrome (MODS). METHODS: A total of 119 patients with MODS were examined with arterial blood gas analysis and serum electrolytes detection for 675 times in this study. RESULTS: Different types of ABD existed in 647 times out of 675 times (95.9%) of blood-gas analyses. There were 270 times (41.7%) of simple ABD, 271 times (41.9%) of double ABD and 106 times (16.4%) of triple ABD. Among which, 404 times (62.4%) were in respiratory alkalosis (RAL), 332 times (51.3%) in metabolic acidosis (MA), 227 times (35.1%) in metabolic alkalosis (MAL) and 167 times (25.8%) in respiratory acidosis (RA). In this study, 79 cases (66.4%) out of 119 cases with MODS died from these kinds of ABD. CONCLUSIONS: It suggests that in the early stage of MODS, RAL with or without hypoxemia may exist, and later on, MA or even triple ABD may occur. In order to detect and correct the primary disorders as early as possible, it is important to keep the balance of hydrolyte. The treatment of primary diseases is also important. Disorders of acid-base balance were corrected according to pH standard values, anion gap (AG) and the potential [HCO(3)(-)] were also calculated simultaneously. When pH was more than 7.50 or lower than 7.20, it is necessary to give drugs of acidity or alkalinity to the patients with ABD to maintain pH value within a normal range.

Journal Article↗

PubMedDate not supplied

Castleman's disease of the leptomeninges--immunohistochemical findings in 2 cases.

OBJECTIVE: Castleman's disease is an uncommon benign lymphoproliferative disorder that arises in lymph nodes. Few cases of Castleman's disease affecting the central nervous system have been described. CASE HISTORY: We report 2 new cases of Castleman's disease confined solely to the leptomeninges. The patients were referred to neurosurgery with presumptive clinical diagnosis of meningiomas. Histological investigation of the operative specimens taken from the abnormal leptomeninges revealed nodular lymphoid areas with multiple germinal centers surrounded by concentrically layered proliferations of small lymphocytes. Histologically, these 2 cases fulfilled the classification criteria for the mixed and for the hyaline-vascular type of Castleman's disease. The immunohistochemical analysis revealed a polyclonal B cell proliferation in the lesions with perifollicular T cell proliferation with the T helper cell predominance. CONCLUSIONS: The authors conclude that Castleman's disease involving the leptomeninges have a similar immunological pattern reported for the disease in extracranial locations and that, though being rare, Castleman's disease should be considered as a differential diagnosis when dealing with mass lesions of leptomeninges.

Aged↗

PubMed1990

Interactions of antimicrobial combinations in vitro: the relativity of synergism.

Interactions of combinations of netilmicin, amikacin, piperacillin, imipenem, azlocillin, ceftazidime or moxalactam were studied in vitro against Pseudomonas aeruginosa, Escherichia coli, Klebsiella pneumoniae and Staphylococcus aureus. Microtiter checkerboard technique was compared with standard killing curve method and with killing curves obtained in kinetic in vitro models mimicking single or multiple dosing regimens according to human pharmacokinetics. Antibiotic combinations were classified as antagonistic, indifferent or synergistic. Disagreement between classification by checkerboard and by kinetic model was found in 14 of 33 combinations studied (42%). Further analysis by standard killing curve method demonstrated that synergism or antagonism is a relative, not an absolute feature of drug combinations against given pathogens. Factors contributing to disagreements included the concentrations studied relative to the bacterial sensitivity, the ratio of concentrations of the two drugs tested, the size of the bacterial inoculum and the endpoint of the interaction assessment. Standard in vitro methods do not consider changes of antibiotic concentrations over time during combination therapy. Concentrations studied are defined according to bacterial sensitivity (fractions of MIC). Therefore, they may or may not relate to those at the infected site. The observed discrepancies between standard methods for testing drug interaction and a model which more closely reflects human pharmacokinetics support the argument that standard synergy testing provides incomplete data to reliably design clinical combination therapy.

Amikacin↗

PubMed1995

Automatic identification of gray matter structures from MRI to improve the segmentation of white matter lesions.

The segmentation of MRI scans of patients with white matter lesions (WML) is difficult because the MRI characteristics of WML are similar to those of gray matter. Intensity-based statistical classification techniques misclassify some WML as gray matter and some gray matter as WML. We developed a fast elastic matching algorithm that warps a reference data set containing information about the location of the gray matter into the approximate shape of the patient's brain. The region of white matter was segmented after segmenting the cortex and deep gray matter structures. The cortex was identified by using a three-dimensional, region-growing algorithm that was constrained by anatomical, intensity gradient, and tissue class parameters. White matter and WML were then segmented without interference from gray matter by using a two-class minimum-distance classifier. Analysis of double-echo spin-echo MRI scans of 16 patients with clinically determined multiple sclerosis (MS) was carried out. The segmentation of the cortex and deep gray matter structures provided anatomical context. This was found to improve the segmentation of MS lesions by allowing correct classification of the white matter region despite the overlapping tissue class distributions of gray matter and MS lesion.

Algorithms↗

PubMed1995

Is the Durie and Salmon diagnostic classification system for plasma cell dyscrasias still the best choice? Application of three classification systems to a large population-based registry of paraproteinemia and multiple myeloma.

There are a number of systems for diagnosing multiple myeloma, myeloma variants and monoclonal gammopathy of undetermined significance. We compared three systems, those according to Durie and Salmon, to Kyle and Greipp, and to the British Columbia Cancer Agency, using material from a population-based registry of 847 patients with a paraproteinemia or multiple myeloma. Of these, 157 underwent both bone marrow and X-ray examinations and were subsequently included in our analysis. The differences between the systems were small, even though in only 64% of the cases the diagnosis according to all three systems was identical. The system used by the British Columbia Cancer Agency turned out to be the shortest and easiest system reviewed here. We propose a more frequent application of this system instead of the more commonly used Durie and Salmon and Kyle and Greipp criteria.

Adult↗

PubMed2003

Noninvasive classification of liver disease in asymptomatic and oligosymptomatic male alcoholics.

The predominant type of liver alteration in asymptomatic or oligosymptomatic chronic male alcoholics (N = 169) admitted to a psychiatric hospital for detoxification was classified by two independent methods: liver palpation and multiple quadratic discriminant analysis (QDA), the latter applied to two parameters reported by the patient (duration of alcoholism and daily amount ingested) and to the data obtained from eight biochemical blood determinations (total bilirubin, alkaline phosphatase, glycemia, potassium, aspartate aminotransferase, albumin, globulin, and sodium). All 11 soft and sensitive, and 13 firm and sensitive livers formed fully concordant groups as determined by QDA. Among the 22 soft and not sensitive livers, 95% were concordant by QDA grouping. Concordance rates were low (55%) in the 73 firm and not sensitive livers, and intermediate (76%) in the 50 not palpable livers. Prediction of the liver palpation characteristics by QDA was 95% correct for the firm and not sensitive livers and moderate for the other groups. On a preliminary basis, the variables considered to be most informative by QDA were the two anamnestic data and bilirubin levels, followed by alkaline phosphatase, glycemia and potassium, and then by aspartate aminotransferase and albumin. We conclude that, when biopsies would be too costly or potentially injurious to the patients to varying extents, clinical data could be considered valid to guide patient care, at least in the three groups (soft, not sensitive; soft, sensitive; firm, sensitive livers) in which the two noninvasive procedures were highly concordant in the present study.

Adult↗