Diagnosis of multiple sclerosis using multifocal ERG data feature fusion.

The purpose of this paper is to implement a computer-aided diagnosis (CAD) system for multiple sclerosis (MS) based on analysing the outer retina as assessed by multifocal electroretinograms (mfERGs). MfERG recordings taken with the RETI-port/scan 21 (Roland Consult) device from 15 eyes of patients diagnosed with incipient relapsing-remitting MS and without prior optic neuritis, and from 6 eyes of control subjects, are selected. The mfERG recordings are grouped (whole macular visual field, five rings, and four quadrants). For each group, the correlation with a normative database of adaptively filtered signals, based on empirical model decomposition (EMD) and three features from the continuous wavelet transform (CWT) domain, are obtained. Of the initial 40 features, the 4 most relevant are selected in two stages: a) using a filter method and b) using a wrapper-feature selection method. The Support Vector Machine (SVM) is used as a classifier. With the optimal CAD configuration, a Matthews correlation coefficient value of 0.89 (accuracy = 0.95, specificity = 1.0 and sensitivity = 0.93) is obtained. This study identified an outer retina dysfunction in patients with recent MS by analysing the outer retina responses in the mfERG and employing an SVM as a classifier. In conclusion, a promising new electrophysiological-biomarker method based on feature fusion for MS diagnosis was identified.

Diagnostic ability of multifocal electroretinogram in early multiple sclerosis using a new signal analysis method.

PURPOSE: To determine if a novel analysis method will increase the diagnostic value of the multifocal electroretinogram (mfERG) in diagnosing early-stage multiple sclerosis (MS). METHODS: We studied the mfERG signals of OD (Oculus Dexter) eyes of fifteen patients diagnosed with early-stage MS (in all cases < 12 months) and without a history of optic neuritis (ON) (F:M = 11:4), and those of six controls (F:M = 3:3). We obtained values of amplitude and latency of N1 and P1 waves, and a method to assess normalized root-mean-square error (FNRMSE) between model signals and mfERG recordings was used. Responses of each eye were analysed at a global level, and by rings, quadrants and hemispheres. AUC (area under the ROC curve) is used as discriminant factor. RESULTS: The standard method of analysis obtains further discrimination between controls and MS in ring R3 (AUC = 0.82), analysing N1 waves amplitudes. In all of the retina analysis regions, FNRMSE value shows a greater discriminating power than the standard method. The highest AUC value (AUC = 0.91) was in the superior temporal quadrant. CONCLUSION: By analysing mfERG recordings and contrasting them with those of healthy controls it is possible to detect early-stage MS in patients without a previous history of ON.

Coding Prony's method in MATLAB and applying it to biomedical signal filtering.

BACKGROUND: The response of many biomedical systems can be modelled using a linear combination of damped exponential functions. The approximation parameters, based on equally spaced samples, can be obtained using Prony's method and its variants (e.g. the matrix pencil method). This paper provides a tutorial on the main polynomial Prony and matrix pencil methods and their implementation in MATLAB and analyses how they perform with synthetic and multifocal visual-evoked potential (mfVEP) signals. This paper briefly describes the theoretical basis of four polynomial Prony approximation methods: classic, least squares (LS), total least squares (TLS) and matrix pencil method (MPM). In each of these cases, implementation uses general MATLAB functions. The features of the various options are tested by approximating a set of synthetic mathematical functions and evaluating filtering performance in the Prony domain when applied to mfVEP signals to improve diagnosis of patients with multiple sclerosis (MS). RESULTS: The code implemented does not achieve 100%-correct signal approximation and, of the methods tested, LS and MPM perform best. When filtering mfVEP records in the Prony domain, the value of the area under the receiver-operating-characteristic (ROC) curve is 0.7055 compared with 0.6538 obtained with the usual filtering method used for this type of signal (discrete Fourier transform low-pass filter with a cut-off frequency of 35 Hz). CONCLUSIONS: This paper reviews Prony's method in relation to signal filtering and approximation, provides the MATLAB code needed to implement the classic, LS, TLS and MPM methods, and tests their performance in biomedical signal filtering and function approximation. It emphasizes the importance of improving the computational methods used to implement the various methods described above.

Peritonitis bacteriana espontánea como forma de presentación de síndrome nefrótico idiopático en un adulto de raza negra / Spontaneous bacterial peritonitis as form of presentation of idiopathic nephrotic syndrome in an adult black race

La peritonitis bacteriana espontánea es una complicación grave y observada a menudo en el síndrome nefrótico infantil. Sin embargo, en los adultos, pese a ser frecuentemente descrita en los textos de nefrología, es una complicación rara. En la revisión realizada sólo 16 casos están publicados con este tipo de complicación en adultos, y no hay ninguno descrito posterior al año 2000. A continuación exponemos el caso de un varón de 25 años, procedente de Senegal, con peritonitis bacteriana espontánea, fracaso renal agudo y coagulopatía por desnutrición como forma de presentación de un síndrome nefrótico florido. Además a través del caso aportado se discuten distintos aspectos de la epidemiología y del manejo de estos pacientes así como las últimas publicaciones sobre las opciones de tratamiento de la glomerulopatía responsable del cuadro

Spontaneous bacterial peritonitis is a serious and frequent complication in childhood nephrotic syndrome. However, this type of complication is very rare in adult nephrotic patients. In the review realized only 15 cases are published with this complication, and none of them after the year 2000. Later we expose the case of a male of 25 years old, proceeding of senegal, with spontaneous bacterial peritonitis, acute renal failure and coagulopatia for malnutrition as form of presentation of a nephrotic syndrome flowery. Besides across the contributed case different aspects of the epidemiology and of the managing of these patients are discussed as well as the last publications on the options of treatment of the glomerulopatia responsible of the clinical symptoms

[Spontaneous bacterial peritonitis as form of presentation of idiophatic nephrotic syndrome in a black adult]. / Peritonitis bacteriana espontánea como forma de presentación de síndrome nefrótico idiopático en un adulto de raza negra.

Spontaneous bacterial peritonitis is a serious and frequent complication in childhood nephrotic syndrome. However, this type of complication is very rare in adult nephrotic patients. In the review realized only 15 cases are published with this complication, and none of them after the year 2000. Later we expose the case of a male of 25 years old, proceeding of senegal, with spontaneous bacterial peritonitis, acute renal failure and coagulopatia for malnutrition as form of presentation of a nephrotic syndrome flowery. Besides across the contributed case different aspects of the epidemiology and of the managing of these patients are discussed as well as the last publications on the options of treatment of the glomerulopatia responsible of the clinical symptoms.

[A 21-year-old male patient with nephrotic syndrome and "idiopathic" AA amyloidosis]. / Varón de 21 años con síndrome nefrótico y amiloidosis AA "idiopática".

A case is reported of a 21 year old man who suffered from Castleman's disease and systemic secondary amyloidosis. He was otherwise healthy until development of a history of edema and nocturia over 3 weeks. Physical examination was normal apart from ankle swelling. Renal biopsy showed amyloid deposits in the glomerulus with gentian violet and congo red. Positive staining by antibody against serum amyloid A protein was demonstrated. Nine months later because of persistent nephrotic syndrome, an abdominal tomography was performed and a mesenteric mass was detected. The patient underwent abdominal surgery. The histopathological examination showed plasma cell variant of Castleman disease and AA amyloidosis in the mass. After the removal of mesenteric mass, the proteinuria gradually decreased and disappeared, and no systemic findings were present.

Varón de 21 años con síndrome nefrótico y amiloidosis AA «idiopática» / A 21 year-old male patient with nephrotic síndrome and AA amyloidosis

Se presenta el caso de un paciente de 21 años de edad, con síndrome nefró- tico y amiloidosis renal, que consultó por edemas en los miembros inferiores y palpebrales de 3 semanas de evolución. A la exploración, salvo los edemas, no había nada a destacar, detectándose en la analítica un síndrome nefrótico. Se realizó una biopsia renal que informó de amiloidosis AA sin encontrar causa que lo justificará. Nueve meses más tarde, ante la persistencia del síndrome nefrótico, se realizó TAC abdominal donde se apreciaba la existencia de una masa que se resecó. El diagnóstico anatomopatológico fue de enfermedad de Castleman, variedad de células plasmáticas. Tras la resección de la masa desaparecieron la proteinuria y las alteraciones analíticas (AU)

A case is reported of a 21 year old man who suffered from Castleman´s disease and systemic secondary amyloidosis. He was otherwise healthy until development of a history of edema and nocturia over 3 weeks. Physical examination was normal apart from ankle swelling. Renal biopsy showed amyloid deposits in the glomerulus with gentian violet and congo red. Positive staining by antibody against serum amyloid A protein was demonstrated. Nine months later because of persistent nephrotic syndrome, an abdominal tomography was performed and a mesenteric mass was detected. The patient underwent abdominal surgery. The histopathological examination showed plasma cell variant of Castleman disease and AA amyloidosis in the mass. After the removal of mesenteric mass the proteinuria was gradually decreased and dissappeared and any sistemic findings were present (AU)