The effects of lossy compression on diagnostically relevant seizure information in EEG signals.

This paper examines the effects of compression on EEG signals, in the context of automated detection of epileptic seizures. Specifically, it examines the use of lossy compression on EEG signals in order to reduce the amount of data which has to be transmitted or stored, while having as little impact as possible on the information in the signal relevant to diagnosing epileptic seizures. Two popular compression methods, JPEG2000 and SPIHT, were used. A range of compression levels was selected for both algorithms in order to compress the signals with varying degrees of loss. This compression was applied to the database of epileptiform data provided by the University of Freiburg, Germany. The real-time EEG analysis for event detection automated seizure detection system was used in place of a trained clinician for scoring the reconstructed data. Results demonstrate that compression by a factor of up to 120:1 can be achieved, with minimal loss in seizure detection performance as measured by the area under the receiver operating characteristic curve of the seizure detection system.

Energy efficient on-sensor processing in Body Sensor Networks.

Body Sensor Networks (BSNs) have tremendous potential in facilitating the real-time monitoring of the health of an individual in their own environment. However to truly exploit this potential, the powerful signal processing and analysis techniques available in the hospital environment must also be deployed in BSNs. In this paper, techniques in algorithm development, communications, hardware architecture and circuit design are described that will achieve the necessary power savings to make intelligent BSNs a reality.

A comparison of quantitative EEG features for neonatal seizure detection.

OBJECTIVE: This study was undertaken to identify the best performing quantitative EEG features for neonatal seizures detection from a test set of 21. METHODS: Each feature was evaluated on 1-min, artefact-free segments of seizure and non-seizure neonatal EEG recordings. The potential utility of each feature for neonatal seizure detection was determined using receiver operating characteristic analysis and repeated measures t-tests. A performance estimate of the feature set was obtained using a cross-fold validation and combining all features together into a linear discriminant classifier model. RESULTS: Significant differences between seizure and non-seizure segments were found in 19 features for 17 patients. The best performing features for this application were the RMS amplitude, the line length and the number of local maxima and minima. An estimate of the patient independent classifier performance yielded a sensitivity of 81.08% and specificity of 82.23%. CONCLUSIONS: The individual performances of 21 quantitative EEG features in detecting electrographic seizure in the neonate were compared and numerically quantified. Combining all features together into a classifier model led to superior performance than that provided by any individual feature taken alone. SIGNIFICANCE: The results documented in this study may provide a reference for the optimum quantitative EEG features to use in developing and enhancing neonatal seizure detection algorithms.

Tubulointerstitial nephritis and uveitis in association with Epstein-Barr virus infection.

The case of a 13.5-year-old girl with acute tubulointerstitial nephritis and uveitis (TINU syndrome) is presented. The etiology of this rare syndrome, which in most cases involves female adolescents and usually regresses spontaneously, is still unknown. An infection-triggered pathological immune reaction has been considered to play a role in the pathogenesis of this disorder. Here we report for the first time the association of TINU syndrome and Epstein-Barr virus infection.

Peripheral multifocal chorioretinitis with panuveitis: clinical and immunogenetic characterization in older patients.

BACKGROUND: The etiology of peripheral multifocal chorioretinitis with panuveitis (MCP) is unclear. Characteristic signs of MCP are punched-out, white chorioretinal lesions of the lower fundus periphery, chronic smoldering chorioretinal inflammation, vitritis, and mild inflammation of the anterior chamber. In this retrospective study we investigated clinical and immunogenetic abnormalities in MCP in older patients. PATIENTS AND METHODS: 20 patients (18 women, 2 men), median age 70.5 years, were investigated clinically by ophthalmologists and were typed for HLA class I antigens using the standard microlymphocytotoxicity test. Typing for HLA-DR antigens was performed by polymerase chain reaction with sequence-specific primers (PCR-SSP). The HLA controls consisted of healthy people (108 for HLA class I, 114 for HLA class II). RESULTS: MCP was bilateral in 18 patients. Disease-related symptoms were present for 8 months (median) before diagnosis. The main presenting symptoms or findings were glaucoma (in 11 patients), visual loss (7), iritis (5), and vitritis (2). Anterior segment changes were frequently seen: keratitic precipitates (32 eyes), anterior chamber cells (25 eyes), aqueous flare (26 eyes), posterior synechiae (22 eyes), secondary glaucoma (15 eyes), and iris neovascularization (8 eyes). All patients had vitritis and typical chorioretinal fundus lesions. Fourteen patients developed cystoid macular edema (bilateral in seven cases). Subretinal neovascularization occurred in three patients. Although systemic medication was given to 17 patients and surgical treatment was performed in 25 eyes, improvement in vision was found in only 6 eyes, but 18 eyes deteriorated markedly (median 5 lines) during follow-up (median 24.5 months). Immunogenetically significant reduced frequencies of HLA-B7 and HLA-DR1 were found; also HLD-DR15(2) was reduced. However, several alleles were increased in MCP, although not significantly: HLA-A31; HLA-B57, HLA-B62; HLA-Cw3, HLA-Cw6; HLA-DR4, HLA-DR7, and HLA-DR8. CONCLUSIONS: MCP is clinically and immunogenetically open to speculation. The present diagnosis and treatment of MCP are insufficient. Further DNA typing methods should clarify, whether HLA-DQ antigens are associated with the disease.

MRI features of craniofacial fibrous dysplasia.

A 13-year-old female with a 4-year history of monostotic fibrous dysplasia had noticed a progressive proptosis of the right eye and diplopia on upward gaze for 4 weeks. A few years previously an incisional biopsy of the skull had verified the presumed diagnosis of fibrous dysplasia with recurrent bleeding into pathologic cystic bony structures of the skull. The patient was known to have craniofacial fibrous dysplasia with involvement of the frontal and intermediate cranial base, the posterior ethmoidal labyrinth, and the sphenoidal and maxillary sinuses. Eye examination showed a reduced visual acuity in the right eye without defects of the visual field. MR imaging showed a fluid-filled cystic cavity in the orbital frontal bone pushing the globe downwards. Four months later she developed similar symptoms on the other side while proptosis of the right eye was regressive. T2-weighted MRI revealed a large fluid-filled cystic cavity with a fluid-fluid level in the upper part of the left orbit. It is concluded that follow-up studies can be easily performed by MRI without additional exposure to radiation. The total extent of osseous involvement can be determined. Thus, MRI may be helpful in deciding between operative or conservative therapy.

[Vascular corrosion specimen of the lumbar spine. Technic--results--application]. / Gefässkorrosionspräparate der Lendenwirbelsäule. Technik-Ergebnisse-Anwendung.

The present paper reports on the preparation of vascular corrosion specimens of the lumbar spine, which permit Three-dimensional representation of the arterial and venous vascular tree. The technique, which uses stained methacrylate, is described and the results are illustrated in several figures. Applications include analysis of surgical approaches and the chances of success, e.g., of spondylodeses.