Classification of quantitative EEG data by an artificial neural network: a preliminary study.

Previous studies from different laboratories have suggested that qEEG could be useful for distinguishing dementia from normality. Our aims were: (1) to study the ability of qEEG to distinguish dementia among different pathological conditions in ambulatory settings; (2) to compare the ability of classical statistical analysis and of neural networks in classifying qEEG data. We were able to obtain a multiple discriminant function using a training set of patients, which classified correctly more than 91% of the qEEGs from an independent group of patients, with less than 5% of false positives. Kohonen's neural network was trained with the same set of patients. This unsupervised learning artificial neural network performed the classification of the independent sample with an accuracy comparable to that of the multiple discriminant function. Our results suggest that the use of unsupervised learning algorithms could be an interesting alternative in the classification of data obtained from psychiatric patients where definition of their clinical profile is not always a simple task.

The leachate composition of an old waste dump connected to groundwater: Influence of the reclamation works.

This study has been carried out in an uncontrolled dump in the suburbs of Buenos Aires, Argentina. This dump still contains solid wastes of different types in direct contact with the human consumption aquifer. After 18 years of overturning the dump was closed in 1992, and the reclamation works started.Three leachate samplings were carried out in three different zones of the dump, selected according to the topography, the age of residues and the degree of water contact. These samplings were done before the reclamation works, at the end, and four months after they were finished. Several chemical parameters, including heavy metals in solid and dissolved fractions, were analyzed.Multivariate analysis (PCA) was performed to help to understand the effects of the labors on leachate composition. The works could be responsible for a temporal increase of dissolved heavy metals and several chemical variables in the leachate. At the sites of the dump where the modifications were carried out, the levels of some elements analyzed recovered their former values a few months after the reclamations works. At the farthest site, the impact and recovery effects of the works on leachate composition, were delayed.

Non-invasive diagnosis of bladder instability using the Bladder Instability Discriminant Index (BIDI).

The purpose of this study was to validate prospectively the BIDI index in the non-invasive diagnosis of bladder instability, as a procedure for clinical evaluation in primary health care of women. 217 patients were studied; 82 with stress incontinence, 39 with urge incontinence and 96 with both symptoms. All patients were studied by specialist physicians, who conducted a clinical evaluation, questionnaire, gynecological and urological examination, stress test, urodynamic assessment and a 7 day frequency/volume study, recording each intake and micturition; data that were used to calculate the BIDI index. The results obtained through the application of the BIDI were compared with the corresponding urodynamic diagnoses, achieving 88% sensitivity and 83% specificity. The use of the BIDI index is suggested as a non-invasive clinical diagnostic method, of low cost and simple performance. It is recommended for treatment control and for taking diagnostic and therapeutic decisions in medical centres lacking proper urodynamic equipment.

Changes in total and polymerized tubulin of the medial basal hypothalamus and adenohypophysis of castrated or hormone-injected rats.

Treatment of orchidectomized rats with LH, FSH or prolactin decreased the tubulin content of the medial basal hypothalamus (MBH), whereas FSH or prolactin augmented it in the adenohypophysis (AH). After castration, negative correlations existed between serum LH and total or polymerized MBH tubulin, whereas in the AH positive correlations were found. After estradiol-progesterone treatment of spayed rats a significant correlation was found between serum LH and the percentage of AH tubulin in the polymerized form.