Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Annual Conference
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Conf Proc IEEE Eng Med Biol Soc · Jan 2015
Comparative StudyComparison of HRV parameters derived from photoplethysmography and electrocardiography signals.
Heart rate variability (HRV) has become a useful tool in analysis of cardiovascular system in both research and clinical fields. HRV has been also used in other applications such as stress level estimation in wearable devices. HRV is normally obtained from ECG as the time interval of two successive R waves. ⋯ Our results show that the smallest error happens in SDNN and SD2 with relative error of 2.46% and 2%, respectively. The most affected parameter is pNN50 with relative error of 29.89%. In addition, in our trial, using the maximum of PPG gave better results than its second derivative.
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Conf Proc IEEE Eng Med Biol Soc · Jan 2015
Sleep stage classification by body movement index and respiratory interval indices using multiple radar sensors.
Disturbed sleep has become more common in recent years. To increase the quality of sleep, undergoing sleep observation has gained interest as an attempt to resolve possible problems. In this paper, we evaluate a non-restrictive and non-contact method for classifying real-time sleep stages and report on its potential applications. ⋯ The accuracy was 79.3% for classification and 71.9% for estimation. This is a novel system for measuring body movements and body-surface movements that are induced by respiration and for measuring high sensitivity pulse waves using multiple radar signals. This method simplifies measurement of sleep stages and may be employed at nursing care facilities or by the general public to increase sleep quality.
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Conf Proc IEEE Eng Med Biol Soc · Jan 2015
Quantitative EEG markers in severe post-resuscitation brain injury with therapeutic hypothermia.
Therapeutic hypothermia has been regarded as one of the most effective post-cardiac arrest (CA) treatments to improve survival and functional recovery. However, many clinical prognostic markers after resuscitation have become less reliable under hypothermia. In this study, we applied and compared two developed quantitative measures - information quantity (IQ) and sub-band IQ (SIQ) - to evaluate the accuracy of EEG markers on predicting cortical recovery under therapeutic hypothermia. ⋯ Contrary to IQ recovery but similarly to NDS scores, the SIQ recovery was not significantly different between the hypothermia (0.66±0.04) and normothermia (0.64±0.04) groups (p>0.05). IQ could identify the presence of high-frequency oscillations during the recovery from severe brain injury. We demonstrated that while SIQ was able to provide additional sub-band EEG information related to the recovery of different brain functions, both early IQ and SIQ markers are able to accurately predict neurologic outcome after CA.
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Conf Proc IEEE Eng Med Biol Soc · Jan 2015
Estimating instantaneous respiratory rate from the photoplethysmogram.
The photoplethysmogram (PPG) obtained from pulse oximetry shows the local changes of blood volume in tissues. Respiration induces variation in the PPG baseline due to the variation in venous blood return during each breathing cycle. We have proposed an algorithm based on the synchrosqueezing transform (SST) to estimate instantaneous respiratory rate (IRR) from the PPG. ⋯ The median RMS error was 0.39 breaths/min for all subjects which ranged from the lowest error of 0.18 breaths/min to the highest error of 13.86 breaths/min. A Bland-Altman plot showed an agreement between the IRR obtained from PPG and reference respiratory rate with a bias of -0.32 and limits agreement of -7.72 to 7.07. Extracting IRR from PPG expands the functionality of pulse oximeters and provides additional diagnostic power to this non-invasive monitoring tool.
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Conf Proc IEEE Eng Med Biol Soc · Jan 2015
A high-accuracy surgical augmented reality system using enhanced integral videography image overlay.
Image guided surgery has been used in clinic to improve the surgery safety and accuracy. Augmented reality (AR) technique, which can provide intuitive image guidance, has been greatly evolved these years. As one promising approach of surgical AR systems, integral videography (IV) autostereoscopic image overlay has achieved accurate fusion of full parallax guidance into surgical scene. ⋯ Preliminary experiments validated that the image accuracy and resolution are improved with the proposed methods. The resolution of the IV image could be promoted to 1 mm for a micro lens array with pitch of 2.32 mm and IES magnification value of 0.5. The relative deviation of accuracy in depth and lateral directions are -4.68 ± 0.83% and -9.01 ± 0.42%.