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PubMed1992

[Automatic (computer-assisted) EEG analysis in comparison with visual EEG analysis in patients following minor cranio-cerebral trauma (a follow-up study)].

The study was designed to examine the clinical applicability and use of computer-assisted EEG-analysis in comparison to visual EEG-analysis in patients with minor head injuries. For this in 31 patients the following examinations were performed within the first 24 hours, one, three and eight weeks after traumatization: EEG, neurological examination and standardized evaluation of subjective complaints. The EEG was analysed visually as well as computer-assisted. The results were compared to the neurological findings and subjective complaints. Reversible posttraumatic EEG-changes were observed in 50% of all patients. The results of computer-analysis and visual analysis were equivalent in respect to baseline-activity (as one of the main characteristic EEG-features). Furthermore, based on computer-assisted analysis a discriminant function is provided, which is of diagnostic and prognostic value in the single patient. We conclude that the computer-assisted EEG-analysis can be a useful alternative in EEG-routine diagnosis after minor head injuries.

Adolescent↗
PubMed1988

Diagnostic efficacy of computerized spectral versus visual EEG analysis in elderly normal, demented and depressed subjects.

Computerized spectral and visual EEG analyses were performed in 35 patients with Alzheimer's disease (AD) and compared to 23 patients with major depression and to 61 healthy elderly controls. In particular, we were interested in the diagnostic efficacy of these two techniques in the identification of cases of AD with only mild cognitive impairment (as measured by the Folstein Mini-Mental State score). For the computer analyzed data, in differentiating AD patients from controls, the spectral pooled parasagittal mean frequency was used. In comparing AD patients to depressed subjects, a combined parasagittal delta and theta spectral score was employed. Visual analysis criteria were based on the severity of generalized EEG abnormalities (with or without focal features). We found that spectral analysis afforded only modest advantages over visual EEG analysis in differentiating AD patients from elderly controls as well as from those with major depression. Since the degree of spectral and visual EEG abnormalities correlated with the severity of dementia, both tests more often correctly classified those AD patients with lower Folstein scores. Also, both tests identified primarily the same patients. We did not find the computer to be more sensitive than the eye in the identification of AD patients with mild impairment. However, computerized spectral data was derived from only 4 channels, while 16 channels and a longer recording time were used for visual analysis. In addition, some areas which have been reported to show EEG abnormalities in AD were not included in the computerized data.

Aged↗
PubMed2025

APAV: An advanced pangenome analysis and visualization toolkit.

Traditional pangenome analysis focuses on gene presence/absence variations (gene PAVs). However, the current methods for gene PAV analysis are insensitive to detect small but valuable mutations within gene regions, and they overlook variations in intergenic regions. Additionally, the visual inspection of PAVs is an important but time-consuming step for pangenome analysis and result interpretation. To address these issues, we present APAV, an advanced toolkit designed for comprehensive PAV analysis and visualization. It integrates gene element-level PAV analysis and provides PAV analysis for arbitrary given regions in a genome. The resulted PAV profile can be visualized and investigated interactively with reports in HTML format, enabling researchers to conveniently verify sequencing read depth, target region coverage, and intervals of absence for each PAV. Furthermore, APAV offers various subsequent analysis and visualization functions based on the PAV profile table, including basic statistics, sample clustering, genome size estimation, and phenotype association analysis. We demonstrated the capability of APAV with pangenome analysis of tumor genomes and rice genomes. Performing PAV analysis at the element level not only provides more accurate information about the variations but also uncovers a larger number of variations for the phenotype-genotype association studies. In the rice genome analysis, we identified over twenty thousand distributed genes and more than fifty thousand distributed genetic elements. In the tumor genome analysis, element-level analysis revealed approximately three times as many phenotype-related genes as gene-level analysis. This indicates that altering the PAV unit from genes to smaller segments or elements can lead to more biological insights.

Software↗
PubMed1990

Pattern-reversal visual evoked potentials in children with migraine: a correlation analysis.

Visual potentials evoked by pattern reversal (PRVEPs) were studied in 64 normal children (age range 7 to 15 years) and in 20 age-matched patients with common and complicated migraine (age range 6 to 16 years). Most of them were studied before and during prophylactic therapy. A Quadristim set (Alvar) was used to present checkerboard patterns on a TV monitor, to amplify the EEG signals and to average and plot the evoked potentials. The potentials were elicited by binocular full-field 2/s checkerboard reversal, recorded from an electrode 4 cm above the inion, and analyzed for latency, amplitude and waveform morphology. The degree of similarity between pairs of PRVEPs was determined by the correlation coefficient. In all our patients no pronounced influence of the disease itself was demonstrated on the PRVEP latencies and amplitudes, but in most of them the correlation coefficients were significantly different from that showing the measure of normal PRVEP variations. Prophylactic medication influenced non-significant increase of the coefficient. This increase seems to be related to recovery from medication in terms of attack frequency. No significant difference in PRVEP results of common and complicated migraine was noticed. The PRVEP distortion can be revealed by the correlation coefficient but not by other PRVEP parameters. Therefore, this parameter may be useful as a sensitive measure of both PRVEP distortion and PRVEP improvement. Our results give further evidence that non-demyelinating disorders, but with ischemic damage and abnormalities in neurotransmitters, can produce measurable changes in PRVEP morphology.

Adolescent↗
PubMed1989

In situ elemental analysis and visualization in cryofixed nervous tissues. X-ray microanalytical investigations of embryological and mature brain, inner ear, photoreceptors, muscle and muscle spindles. Comparison of preparation methods for analysis and visualization at cellular and subcellular levels.

For meaningful X-ray microanalysis (XRMA) in biology and medicine, the development of preparative and quantitative methods has been necessary. The methods need to preserve close to in vivo distribution of diffusible ions with at the same time reasonable morphological preservation of the tissue. Analyses at low and middle microanalytical resolution are useful at the initial stages of an investigation or when data from large populations of samples have to be acquired. Cryomicrotomy, which makes it possible for the single cells within semi-thin and thick cryosections examined by X-ray microanalysis to be further characterized histochemically (enzyme and substrate content), has been adopted for several pathophysiological studies. The method is particularly suitable for the analysis of complex morphological tissues with many cell types as in the brain or sensory organs of the internal ear. For microanalysis at the subcellular level, we developed a preparative procedure based on the frozen fixed preparation which is freeze-dried in vacuo at -80 degrees C and then at the same temperature, without breaking the vacuum, impregnated with a low-temperature Lowicryl-type resin. The resin is polymerized by u.v. light. This method prevents redistribution of the ions in the tissue and retains the antigenicity of the tissue. A considerable number of cells can be analysed simultaneously and the elemental composition in different cell compartments can be compared due to the similar analytical conditions within the section. An alternative to thin plastic sections of freeze-dried material is thin cryosections cut at -150 degrees C and analysed at low temperatures. Although some methodological problems still exist in preparation of cryosections, this type of section is potentially the most useful in analysis of diffusible ions, especially calcium which in most biological systems is present in very low concentrations. New preparative techniques for XRMA brought severe problems in visualization of the specimens prepared by cryomethods. Charging, low contrast, mass loss and contamination, which are often negligible in conventional electron microscopy, have still to be solved in XRMA of cryoprepared specimens. However, the methods of semi-thin and thick cryosectioning and low-temperature embedding were successfully used for analysis of cells and organelles and for the study of fluids in restricted biological spaces such as the inner ear, muscle spindles and ventricles of the brain in rats. Accordingly, examinations which were impossible by micropuncture and ion selective techniques could be carried out by XRMA.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1990

Bone trabecular pattern analysis in Down syndrome with the use of computed panoramic radiography. Part II: Visual pattern analysis with the frequency and gradational enhancement.

Visual pattern analysis of mandibular bone trabeculation of 51 patients with Down syndrome and 78 normal persons was performed by using rotational panoramic radiography with a laser scan system. The findings for patients with Down syndrome were consistent with geromorphism, one of the somatic characteristics of Down syndrome.

Adolescent↗
PubMed1992

[Visual and computer evaluation of diazepam-induced EEG changes in epilepsy for localization of epileptogenic lesion].

Diazepam-induced EEG changes were analyzed both visually and by computer in epilepsy for localization of epileptogenic lesion. The results demonstrated that changes in beta spectral were diminished in 11/24 or 15/25 cases, but regionally increased in 3/24 or 3/25 patients overlying the epileptogenic lesion or area of EEG abnormalities. Diazepam-induced delta spectral power was usually increased (9/24), but occasionally focally reduced (3/24) over the lesion. The percentage of positive findings for localization was 38% with visual analysis and 46% with spectral analysis in beta spectral power, 38% in delta spectral power, and 67% with the analysis in combined beta with delta, and 83% with four independent tests. Spectral analysis was more sensitive than visual analysis, and it was a useful supplement to visual analysis, to general EEG evaluation, and to CT. Finally, the study emphasized that a localizing diagnosis to define the epileptogenic lesion should be based on the combination of a multitude of independent tests.

Adolescent↗
PubMed1990

Comparison of quantitative coronary angiography to visual estimates of lesion severity pre and post PTCA.

Quantitative coronary angiographic measurements and visual estimates of coronary lesion severity were compared prospectively before, immediately following, and 6 months following percutaneous transluminal coronary angioplasty. Mean percent diameter stenosis before angioplasty was 87.9 +/- 9.9% by visual analysis and 64.6 +/- 9.2% by quantitative coronary angiography (p = 0.0001). Differences between these two techniques were also found immediately post-angioplasty (visual analysis 29.5 +/- 11.8%, quantitative coronary angiography 22.8 +/- 11.8%, p = 0.0002) and at 6 months (visual analysis 46.5 +/- 27.4%, quantitative coronary angiography 30.2 +/- 20.4%, p = 0.0001). These differences significantly affected the determination of restenosis by three definitions. (1) Lesion recurrence with greater than or equal to 50% stenosis at follow-up: 38 of 92 (41%) by visual analysis versus 20 of 92 (22%) by quantitative coronary angiography (p less than 0.01). (2) Increase of greater than or equal to 30% stenosis: 34 of 92 (37%) by visual analysis versus 20 of 92 (22%) by quantitative coronary angiography (p less than 0.01). (3) Loss of 50% of previous improvement: 31 of 92 (34%) by visual analysis versus 24 of 92 (26%) by quantitative coronary angiography (p = 0.08). In addition, determination of success or failure of percutaneous transluminal coronary angioplasty was affected by the interpretative technique, but these differences were not statistically significant. We conclude that visual estimates of lesion severity are consistently and significantly higher than quantitative measurements. Consequently, restenosis rates, using currently applied definitions, differ considerably depending on the method of analyzing lesion severity.

Angiography↗
PubMed1992

Analysis of data in idiographic research. Issues and methods.

Time-series and single-subject designs are being advocated for use in rehabilitation research to document the effectiveness of therapeutic intervention procedures. The argument is made that these designs are practitioner-oriented and practice-based. Acceptance and application of single-subject procedures by rehabilitation researchers will depend on the development of reliable and accurate methods of data analysis. Previous research suggests that traditional visual analysis of graphed data is unreliable and that quantitative supplements to visual analysis should be included in single-subject investigations. The advantages and limitations of two commonly advocated supplements to visual analysis are examined. The two supplemental procedures are the split-middle method of trend estimation and the resistant trend line. One advantage of the resistant trend line is that it does not make the assumption of a linear pattern in single-subject data. The argument is made that the resistant trend line is the preferred method and should be selected over the more commonly used split-middle method of trend estimation. The advantages and limitations of other quantitative procedures are briefly examined.

Analysis of Variance↗
PubMed1990

[Quantification of the extent of myocardial infarction by thallium-201 single photon emission computed tomography: comparisons with post-mortem findings].

A circumferential profile analysis with a two-dimensional polar representation of thallium(Tl)-201 myocardial single photon emission computed tomograms (SPECT) is an objective and quantitative method to evaluate myocardial infarction (MI). However, the diagnostic capability depends on the normal range of thallium distribution. Therefore, the quantitative analysis of Tl-201 myocardial SPECT was correlated with the pathological findings of the heart in 50 autopsy cases (28 with MI; 22 without MI) to determine the lower normal limits at which we can precisely determine the extent of MI on a quantitative basis. For correctly detecting the extent of MI, the lower normal limits were 2.5 standard deviations below the mean values calculated using profiles normalized to the maximum pixel count observed in each profile. Using this lower normal limit, the sensitivity was 63.8%; specificity was 87.4%; and accuracy was 80.7% for determining the extents of ischemic lesions, though these values were lower than those obtained by visual analysis. However, for detecting MI, the sensitivity by quantitative analysis was 97% which was higher than that by visual analysis. A medium sized (2.5 cm) non-transmural infarction, undetectable by visual analysis, was detectable by two-dimensional polar representations. However, the specificity of detecting MI was low (59%), and most of the false positive studies were observed in cases of valvular disease, coronary artery disease or other cardiac complications. The detectability of the extent of MI varied according to the location of the lesion. False negative lesions were most frequently observed in the septal region; false positive lesions were most frequently observed at the posterolateral regions of the dilated hypertrophic hearts. The septal region located at the peripheral portion of the MI and septal hypertrophy in cases of hypertension, were the likely negative cases, thus, these pathological characteristics may explain the high incidence of false negative results in the septal region quantitatively as well as by visual analysis. In cases with dilated hearts, the radioactivity of the thallium at the posterolateral region was more reduced by absorption compared with that in the non-dilated hearts. This reduction in counts was empirically regarded as abnormal lesions by visual analysis, however, the same situation can objectively and automatically be recognized as false positive by quantitative analysis. We concluded that quantitative analysis by Tl-201 myocardial SPECT is useful for evaluating myocardial infarction automatically, but care must be exercised concerning possible false positive diagnosis in cases with dilated hypertrophic hearts.

Aged↗
PubMed1979

Electroencephalographic quantification by time domain analysis in normal 7--15-year-old children.

Automatic EEG analysis was performed on 239 apparently healthy school age children. The children were classed in 3 age groups: (1) average age of 7; (2) average age of 11; (3) average age of 15. A time analysis method, comparable to classical visual analysis, permitted quantification of the records. The mean amplitude, frequency and percentage time for alpha and theta rhythms were determined for each subject for fronto-central and centro-occipital derivations bilaterally. Records were performed during periods of rest with eyes open and eyes closed. During hyperventilation, records were taken with eyes closed. The normal ranges of parameters were determined by calculating their means and standard deviations, for each age group under each recording condition. Delta and beta rhythm values were not calculated, because of their rarity in this apparently normal sample. The precision obtained by automatic analysis could not have been obtained by means of classical visual analysis. The present findings suggest that the statistical analysis of well-defined groups of normal and pathological children could be of significant value.

Adolescent↗
PubMed1989

[A new computed tomography method for quantitative analysis of abdominal aortic atherosclerosis].

Clinical evaluation of aortic atherosclerosis has been most commonly performed by visual analysis of aortic calcification on conventional radiographs or X-ray CT. However, precise evaluation of the degree of calcification or mild changes with increasing age can be difficult by these methods of visual analysis. A new quantitative method of evaluating the abdominal aortic atherosclerosis using CT is reported. Target CT scans of the abdominal aorta were performed at the level of the 1st, 3rd and 4th lumbar vertebrae. Two circular regions of interest (ROI) were selected along the outer margin and inner margin of the abdominal aortic wall on CT images, since it was difficult to precisely trace the aortic wall. Histograms of CT value for each pixel were made from two ROIs. A histogram at the ROI of the outer margin was depicted using class values over the maximum CT value in histogram at the ROI of inner margin which indicated flowing blood. A sum of products of the value in each class by the number in that class was divided by the aortic diameter. The value thus obtained was defined as the atherosclerotic index (S.I.). Forty-five cases were studied with this method. Six cases were excluded because of artifacts. The remaining 39 cases (16 males, 23 females) were analyzed. S.I. increased with aging and was higher in men than in women. However, it increased more rapidly in women (8.68/year) than in men (2.73/year). Because this new method employed the CT value, it is more objectively quantitative than previous methods of visual analysis in evaluating abdominal aortic atherosclerosis.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1992

Comparison of angiographic center and local site analysis of PTCA results in a multicenter angioplasty-restenosis trial. The M Heart Group.

We compared three methods of coronary stenosis (S) sizing in a multihospital PTCA restenosis trial: visual analysis by independent observers, single point caliper measurements, and quantitative coronary angiography (QCA). Cine films from 50 patients were submitted from the clinical site to the quantitative angiographic center, where visual analysis and computer quantitation were performed. Regression analysis revealed a correlation coefficient of .857 for caliper vs. QCA (p less than .0001) and .876 for visual observation vs. QCA (p less than .0001). No significant differences were found between any of the 3 methods for pre- or post-PTCA stenosis values. However, QCA yielded smaller PTCA changes in stenosis severity than either caliper or visual observation (p less than .05). Both caliper and visual methods correlated well with QCA in assessing stenosis size pre- and post-PTCA. Trained observers can visually assess lesion severity with accuracy approaching QCA. QCA is likely to be less expensive when compared to visual analysis by three experienced observers and should be the method used for estimating the results of PTCA in clinical trials.

Adrenal Cortex Hormones↗
PubMed1992

Weighting according to location in computer-assisted glaucoma visual field analysis.

In recent years several aids for automated interpretation of visual field data have been suggested. We believed that incorporation of thorough knowledge of normal visual field variability would allow improvements in the performance of such aids since more attention would be paid to field results in areas with low physiological variability. Two visual field models for classification of fields in glaucoma based on comparisons of sensitivity values in the upper and lower hemifields and on analysis of test point clusters with diminished sensitivity were compared. Both models were constructed using logistic regression analysis in 101 normal eyes and 101 eyes with glaucoma. The first, more traditional model assumed Gaussian distributions of deviations from age-corrected normal thresholds and constant variability across the field (non-weighted model). The second model took into account empirically determined variability of pointwise threshold results and of cluster volumes in various visual field regions (weighted model). The two models were subsequently tested on an independent material of 163 normal eyes and 76 eyes with glaucoma. The weighted model gave significantly better classification of the fields in both materials. Accounting for physiological threshold variability can offer significant advantages in the construction of perimetric analysis aids for detection of glaucoma.

Adult↗
PubMed1977

The asymmetrical visual evoked potential to pattern reversal in one half field and its significance for the analysis of visual field defects.

The consistency of the major positive component (P100) of the full-field pattern-reversal response provides a clinically valuable and objective means of detecting visual field defects. Its normally symmetrical distribution about the midline of the occipital scalp results from the summation of two highly asymmetric half-field responses, each of which shows the positive component well lateralised with a widespread distribution on the ipsilateral side. Stimulation of each eye in patients with bitemporal and homonymous hemianopias results in two characteristic patterns of asymmetry, named 'crossed' and 'uncrossed' respectively, in which the major positivity is consistently recorded on the side ipsilateral to the preserved half field. Recordings from a patient after occipital lobectomy confirm the authors' previous suggestion that although the major positive component is recorded from the ipsilateral scalp the typical asymmetric half-field response is generated in the contralateral hemisphere.

Action Potentials↗
PubMed1992

Measurement of the 2D affine Lie group parameters for visual motion analysis.

A class of linear operators is presented for estimating the local components of 2D translation, dilatation, rotation, and the shear/deformations which span the six degrees of freedom of motion of arbitrarily textured surfaces. This results in a model of visual motion analysis which proposes that the local transformations in the image are analysed by decomposing them into the six one-parameter subgroups of the 2D affine group. Each of the required invariant integral operators are easily specified by the characters of these six subgroups. The 2D affine group, however, does not have a simple structure. It is a Lie group which possesses a semi-direct product manifold, and classical harmonic analysis cannot proceed unless some mechanism is prescribed to isolate the 2D 'general linear' transformations from the 2D translations. It must also do so using measures which receive only local support from the image, since the global affine group model is only valid tangentially. A form of 'active perception' is thereby implicated; it is proposed that spatial indexing and 2D tracking is needed in order to form reliable estimates of 3D motion parameters using local operators in a data-driven fashion.

Humans↗