| 1. |
- Folke, Mia, et al.
(författare)
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End tidal carbon dioxide measurement using an electro acoustic sensor
- 2004
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Ingår i: Annual International Conference of the IEEE Engineering in Medicine and Biology - Proceedings. - 0780384393 ; , s. 3452-3455
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- End tidal carbon dioxide measurement with an electro-acoustic sensor is demonstrated. The sensor consists of an acoustic resonator coupled to a low cost electro-acoustic element. By simultaneous measurements with a reference sensor, the new device was tested on subjects performing exercise, hypo- and hyperventilation whereby the CO2 concentration ranged from 2.1 to 7.0 kPa. The output from the experimental device correlated well with the reference CO2 readings with a correlation coefficient of 0.976. Response time for expiration less than 0.8 seconds was noted. The new device could be useful in situations where selectivity to other gases is not important.
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| 2. |
- Johansson, Anders J
(författare)
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Performance of a radio link between a base station and a medical implant utilising the MICS standard
- 2004
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Ingår i: Conference Proceedings. 26th Annual International Conference of the IEEE Engineering in Medicine and Biology Society. - 0780384393 ; 26, s. 2113-2116
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Konferensbidrag (refereegranskat)abstract
- Modern medical implants are of increasing complexity and with that, the need for fast and flexible communication with them grows. A wireless system is preferable and an inductive link is the most commonly used. But it has the drawback of a very short range, essentially limited to having the external transceiver touching the patient. The Medical Implant Communication System, MICS, is a standard aimed at improving the communication distance. It operates at a higher frequency band between 402 MHz and 405 MHz. We have by simulations and measurements investigated the channel properties of this band and calculated the link performance for a typical implant application. The result is a link speed between a base station and a bedridden patient of 600 kbit bits per second with a bit error rate of 2% in the downlink to the implant and 1 % in the uplink to the base station. Conclusions on the necessary complexity of the base station are also given
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| 3. |
- Johansson, Rolf, et al.
(författare)
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Adaptation of Multi-Joint Movements during Postural Disturbances.
- 2004
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Ingår i: Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Conference. - 1557-170X. - 0780384393 ; 1, s. 149-152
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Konferensbidrag (refereegranskat)abstract
- The objective was to investigate the adaptation ofthe multi-segmented body movements induced over time byvibratory proprioceptive stimulation of the calf muscles and by galvanic vestibular stimulation. Twelve normal subjects were with eyes open or eyes closed exposed to vibratory stimulation of two different amplitudes and frequencies, or to simultaneously applied galvanic and vibratory stimulation. Multi-input multi-output system identification methods as well as quantitative analysis were applied to the biomechanical experimental data of anteroposterior and lateral body movements and torques induced towards the ground. The immediate adaptive response to the stimulation onset was that the subjects adopted a more rigid posture with coordinated movements of primarily head-shoulder and headhip body segments. The body-movement amplitudes at allmeasured sites as well as the amplitudes of the ground support forces decreased over time as a result of another, somewhat slower adaptation process. The subjects required more time to adapt to a rigid movement pattern when the subjects were simultaneously exposed to both galvanic and vibratorystimulation. Moreover, the accuracy of the MIMO model andcorrelation analysis between measured torque variance andhead; shoulder; hip and knee movement variance suggests thatforce platform recordings reflect both in anteroposterior and lateral direction the body movements at these sites.
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| 4. |
- Löfgren, N., et al.
(författare)
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On evaluation of spectrum estimators for EEG
- 2004
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Ingår i: Proceedings Of The 26th Annual International Conference Of The IEEE Engineering In Medicine And Biology Society. - : IEEE. - 0780384393 ; 1, s. 305-9
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Konferensbidrag (refereegranskat)abstract
- In the search for how neonatal EEG is affected by asphyxia it is of importance to find reliable estimates of EEG power spectra. Several spectral estimation methods do exist, but since the true spectra are unknown it is hard to tell how well the estimators perform. Therefore a model to generate simulated EEG with known spectrum is proposed and the model is used to evaluate performance of several parametric and Fourier based spectral estimators.
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| 5. |
- Lönnblad, Jens, et al.
(författare)
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Optimization of wireless Bluetooth
- 2004
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Ingår i: Annual International Conference of the IEEE Engineering in Medicine and Biology - ProceedingsVolume 26 III. - 0780384393 ; , s. 2133-2136
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Within this study, three different Bluetooth™ sensor systems, replacing cables for transmission of biomedical sensor data, have been designed and evaluated. The three sensor architectures are built on 1-, 2- and 3-chip solutions and depending on the monitoring situation and signal character, different solutions are optimal. Essential parameters for all systems have been low physical weight and small size, resistance to interference and interoperability with other technologies as global- or local networks, PC's and mobile phones. Two different biomedical input signals, ECG and PPG (photoplethysmography), have been used to evaluate the three solutions. The study shows that it is possibly to continuously transmit an analogue signal. At low sampling rates and slowly varying parameters, as monitoring the heart rate with PPG, the 1-chip solution is the most suitable, offering low power consumption and thus a longer battery lifetime or a smaller battery, minimizing the weight of the sensor system. On the other hand, when a higher sampling rate is required, as an ECG, the 3-chip architecture, with a FPGA or micro-controller, offers the best solution and performance. Our conclusion is that Bluetooth™ might be useful in replacing cables of medical monitoring systems.
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| 6. |
- Seoane, Fernando, 1976-, et al.
(författare)
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Brain electrical impedance at various frequencies : the effect of hypoxia
- 2004
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Ingår i: Proceedings of the 26th Annual International Conference of the IEEE EMBS, San Francisco, CA, USA • September 1-5, 2004. - : IEEE Engineering in Medicine and Biology Society. - 0780384393 ; 3, s. 2322-5
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Konferensbidrag (refereegranskat)abstract
- Non-invasive multi-frequency measurements of transcephalic impedance, both reactance and resistance, can efficiently detect cell swelling of brain tissue and can be used for early detection of threatening brain damage. We have performed experiments on piglets to monitor transcephalic impedance during hypoxia. The obtained results have confirmed the hypothesis that changes in the size of cells modify the tissue impedance. During tissue inflammation after induced hypoxia, cerebral tissue exhibits changes in both reactance and resistance. Those changes are remarkably high, up to 71% over the baseline, and easy to measure especially at certain frequencies. A better understanding of the electrical behaviour of cerebral tissue during cell swelling would lead us to develop effective non-invasive clinical tools and methods for early diagnosis of cerebral edema and brain damage prevention.
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| 7. |
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