Measurement and quantification of generalized tonic-clonic seizures in epilepsy patients by means of accelerometry--an explorative study.

Epilepsy is one of the most common neurological diseases, which has a cumulative lifetime incidence of 3%. Two to threefold increased morbidity and mortality rates are reported, especially if generalized tonic-clonic seizures (GTCS) occur. A wireless small and user-friendly detection system would be helpful in early identification of seizures. This could minimize the risk of seizure-related injuries and further allow complete seizure frequency documentation, especially in a non-clinical private setting. The aim of our study was to develop a design and to conduct an exploratory validation of an accelerometry (ACM)-based detection system for GTCS detection in real-time. Patients were recruited via the Epilepsy Monitoring Unit at the Department of Neurology, Medical University Innsbruck. In three out of 20 patients, four GTCS could be recorded. The ACM sensors recorded increased activities at the stated seizure time, which clearly differed from everyday movements. The temporary sensitivity (100%), specificity (≥88%) and the positive predictive value (≥75%) of the detection suggests a promising alarm/false alarm ratio. The validity of the detection device has to be evaluated with more data in order to be able to significantly confirm the positive results and to further develop a cut-off algorithm for automatic seizure detection.

Development and alarm threshold evaluation of a side rail integrated sensor technology for the prevention of falls.

OBJECTIVE: Patient falls constitute a serious problem both for the persons fallen and for the institutions involved. Bed-exit alarm systems are used to reduce patient falls. Existing bed-exit alarm systems have several disadvantages depending on the technology used. As in "Evaluation of Bed-Exit Alarms" stated, restless, light weighted, uncooperative, incontinent and confused patients require different systems. The aim of this work is to present the research and development process of the integrated, universally applicable BUCINATOR bed-exit-alarm system. METHODS: The use-case technique was applied to capture the functional requirements for the development of the new integrated bed-exit alarm system. An experimental study was carried out to collect data regarding preliminary sensitivity and specificity for alarm set-off. RESULTS: Major identified requirements for an optimized bed-exit alarm system were usability, wide range usage, low costs, hygiene factors, integration into nursing beds and nurse call systems and an adequate alarm/false alarm ratio with early alarm trigger functionality. On the basis of the criteria mentioned above, a sensor system was developed, comprising tubes with an air-filled passageway attached on the top of side rails. These tubes are coupled via lines to transducers which trigger an alarm when a predetermined level of pressure is reached. Both the preliminary sensitivity (96.0%) and the specificity (>or=95.5%) of the trigger level indicate a satisfactory alarm/false alarm ratio which is now to be evaluated in a clinical trial. CONCLUSIONS: After experimental testing, BUCINATOR shows great potential to be a reliable bed-exit alarm system. In general, bed-exit alarm systems with extended features could play a major role in ambient assisted living technologies. LIMITATIONS: Besides the theoretical evaluation, it will be imperative to perform more tests and to gather more data about the effect on fall rates and resulting injuries.