Technology and Health Care - Volume 21, issue 4

Authors: Mortazavi, S.M.J.

Article Type: Review Article

Abstract: Energetic solar particle events (SPE) which are among the main sources of ionizing radiation can be life threatening to astronauts who are not adequately protected. To date, physical shielding of spacecrafts and inducing radioresistance by using radioprotectors have been proposed by different investigators. Mortazavi et al. have previously reported that screening of the candidates of long-term space missions by conducting Ground-based in vitro adaptive response studies before any mission identifies the individuals who respond well to low levels of ionizing radiation and reveal high magnitudes of radioadaptive response. On the other hand, Mortazavi et al. have recently showed that radiofrequency-induced …adaptive response can be used as a method for decreasing the risk of infection caused by immunosuppression during deep space missions. Furthermore, over the past years the radioresistance induced by a wide variety of radioprotectors has been studied. According to classical radiobiology, chemical radioprotective agents must be administered before irradiation or at the time of irradiation, to increase the mean survival rate of the exposed individuals. A revolution in this paradigm was started in 2010, when investigators reported that a diet supplemented with antioxidants administered starting 24 h after total-body irradiation is more effective than if given soon after the exposure (radiation mitigation). This finding along with the above mentioned interventions open new horizons in inducing biological radioresistance against unpredictable high levels of radiation due to solar particle events. This wide time window indeed enables astronauts to firstly evaluate their radiation doses before making any decision on the type of intervention. As major solar particle events last for hours, astronauts will be able to consult distinguished radiation biologists via satellite telecommunication before choosing any medical intervention. Show more

Keywords: Astronauts, space missions, cosmic radiation, solar radioactivity, dose modifiers, radioprotectors

DOI: 10.3233/THC-130732

Citation: Technology and Health Care, vol. 21, no. 4, pp. 285-289, 2013

Authors: Hossen, A. | Jaju, D. | Al-Ghunaimi, B. | Al-Faqeer, B. | Al-Yahyai, T. | Hassan, M.O. | Al-Abri, M.

Article Type: Research Article

Abstract: Background: Obstructive Sleep Apnea (OSA) is the cessation of breathing during sleep due to the collapse of upper airway. Polysomnographic recording is a conventional method for detection of OSA. Although it provides reliable results, it is expensive and cumbersome. Thus, an advanced non-invasive signal processing based technique is needed. Objective: The main purpose of this work is to predict the severity of sleep apnea using an efficient wavelet-based spectral analysis method of the heart rate variability (HRV) to classify sleep apnea into three different levels (mild, moderate, and severe) according to its severity and to distinguish them from …normal subjects. Methods: The standard FFT spectrum analysis method and the soft-decision wavelet-based technique are to be used in this work in order to rank patients to full polysomnography. Data of 20 normal subjects and 20 patients with mild apnea and 20 patients with moderate apnea and 20 patients of severe apnea are used in this study. The data is obtained from the sleep laboratory of Sultan Qaboos University hospital in Oman. Four different classification versions have been used in this work. Results: Accuracy result of 90% was obtained between severe and normal subjects and 85% between mild and normal and 75% between severe and moderate and 83.75% between normal and patients. Conclusions: The VLF/LF power spectral ratio of the wavelet-based soft-decision analysis of the RRI data after a high-pass filter resulted in the best accuracy of classification in all versions. Show more

Keywords: Obstructive sleep apnea, severity of apnea, HRV, FFT, wavelet analysis

DOI: 10.3233/THC-130724

Citation: Technology and Health Care, vol. 21, no. 4, pp. 291-303, 2013

Authors: Shimizu, Yasutomo | Javadzadegan, Ashkan | Hayase, Toshiyuki | Ohta, Makoto

Article Type: Research Article

Abstract: Background: Plaques in blood vessels exhibit a wide range of stiffness depending on disease conditions: stiffness is an important factor in plaque behavior. The geometrical change in plaque based on its behavior can affect blood flow patterns. Thus, it is important to study both blood flow and deformation of plaques and blood vessels. Objective: This study aims to identify the differences in flow conditions between in vitro models to discuss experimental materials for arterial wall and flow observation. Methods: In order to observe the blood flow pattern and plaque deformation simultaneously, a PVA-H stenosis model was …used. In addition, a silicone model was also used as a rigid-like model for comparison with the PVA-H model. PIV was employed to measure the flow velocity distribution and determine the flow levels in the models. Results: PVA-H model exhibits expansion with an increase in upstream pressure and silicone model maintains the diameter. The expansion depends on their mechanical properties and influences flow conditions such as velocity changes and RAP in the parent artery. The balance between the expansion and change in flow conditions determines the final geometries of PVA-H model and flow pattern. Conclusions: The results suggest that the stiffness measurement for blood vessels and plaques such as ultrasound measurements would be important for accurate treatments. Show more

Keywords: Biomodel, PVA-H, silicone, PIV, reattachment point, plaque stiffness

DOI: 10.3233/THC-130725

Citation: Technology and Health Care, vol. 21, no. 4, pp. 305-314, 2013

Authors: Kubosch, D. | Windolf, M. | Milz, S. | Südkamp, N.P. | Strohm, P.C.

Article Type: Research Article

Abstract: Background: Anterior spondylodesis with bone grafting for fusion of spinal motion segments is a common procedure in clinical routine. Bone grafts for fusion include autologous, allogenic and xenogenic grafts that are inserted in the unstable spinal motion segment. Nevertheless, biomechanical data for autologous, allogenic and xenogenic grafts are rare. Objective: The purpose of this study was to conduct biomechanical comparison of native and conserved bone grafts used in spondylodesis of the spine. Methods: Grafts examined were native ovine tricortical iliac crest grafts, bovine cancellous bone blocks and ovine, tricortical iliac crest grafts, conserved in the …same way as the bovine cancellous bone blocks. The grafts were tested biomechanically to failure. Compared parameters were maximum torque, maximum rotation angle and graft stiffness at failure. The Mann-Whitney-U test with Bonferroni adjustment was used for statistical analysis. Results: Maximum torque at failure of the bovine cancellous bone graft did not differ significantly from that of the native ovine tricortical graft. Comparison of the conserved ovine tricortical graft revealed significantly lower values compared to the native ovine tricortical bone graft. Maximum rotation angle at failure of the untreated ovine tricortical bone grafts was significantly higher compared to the other grafts tested. Regarding graft stiffness no significant differences were found. Conclusions: Based on the functional demands exerted on the spinal motion segment, our results suggest that torsional strength and deformational behavior of the bone graft influence the stability of the spondylodesis. The native tricortical graft best fulfills this requirement. Show more

Keywords: Spinal fusion, bone graft, spondylodesis, autograft, xenograft

DOI: 10.3233/THC-130731

Citation: Technology and Health Care, vol. 21, no. 4, pp. 315-322, 2013

Authors: Dawadi, Prafulla N. | Cook, Diane J. | Schmitter-Edgecombe, Maureen | Parsey, Carolyn

Article Type: Research Article

Abstract: Background: The goal of this work is to develop intelligent systems to monitor the wellbeing of individuals in their home environments. Objective: This paper introduces a machine learning-based method to automatically predict activity quality in smart homes and automatically assess cognitive health based on activity quality. Methods: This paper describes an automated framework to extract set of features from smart home sensors data that reflects the activity performance or ability of an individual to complete an activity which can be input to machine learning algorithms. Output from learning algorithms including principal component analysis, support vector …machine, and logistic regression algorithms are used to quantify activity quality for a complex set of smart home activities and predict cognitive health of participants. Results: Smart home activity data was gathered from volunteer participants (n=263) who performed a complex set of activities in our smart home testbed. We compare our automated activity quality prediction and cognitive health prediction with direct observation scores and health assessment obtained from neuropsychologists. With all samples included, we obtained statistically significant correlation (r=0.54) between direct observation scores and predicted activity quality. Similarly, using a support vector machine classifier, we obtained reasonable classification accuracy (area under the ROC curve=0.80, g-mean=0.73) in classifying participants into two different cognitive classes, dementia and cognitive healthy. Conclusions: The results suggest that it is possible to automatically quantify the task quality of smart home activities and perform limited assessment of the cognitive health of individual if smart home activities are properly chosen and learning algorithms are appropriately trained. Show more

Keywords: (Methodological) machine learning, smart environments, behavior modeling, (medical) cognitive assessment, MCI, dementia

DOI: 10.3233/THC-130734

Citation: Technology and Health Care, vol. 21, no. 4, pp. 323-343, 2013

Authors: Hossen, Abdulnasir

Article Type: Research Article

Abstract: Background: Essential tremor (ET) and the tremor in Parkinson's disease (PD) are the two most common pathological tremor with a certain overlap in the clinical presentation. Objective: The main purpose of this work is to use an artificial neural network to select the best features and to discriminate between the two types of tremors using spectral analysis of tremor time-series recorded by accelerometry and surface EMG signals. Methods: The Soft-Decision wavelet-based technique is to be used in this work in order to obtain a 16 bands approximate spectral representation of both accelerometer and two EMG signals …of two sets of data (training and test). The training set consists of 21 ET subjects and 19 PD subjects while the test set consists of 20 ET and 20 PD subjects. The data has been recorded for diagnostic purposes in the Department of Neurology of the University of Kiel, Germany. A neural network of the type feed forward back propagation has been used to find the frequency bands associated with the different signals that yield better discrimination efficiency on training data. The same designed network is used to discriminate the test set. Results: Efficiency result of 87.5% was obtained using two different bands from each of the three signals under test. Conclusions: The artificial neural network has been used successfully in both feature extraction and in pattern matching tasks in a complete classification system. Show more

Keywords: Artificial neural networks, spectral analysis, wavelet-decomposition, feature, extraction, pattern matching, PD, ET, Accelerometer, EMG

DOI: 10.3233/THC-130735

Citation: Technology and Health Care, vol. 21, no. 4, pp. 345-356, 2013

Authors: Javadzadegan, Ashkan | Shimizu, Yasutomo | Behnia, Masud | Ohta, Makoto

Article Type: Research Article

Abstract: Background: Flow recirculation and shear strain are physiological processes within coronary arteries which are associated with pathogenic biological pathways. Distinct Quite apart from coronary stenosis severity, lesion eccentricity can cause flow recirculation and affect shear strain levels within human coronary arteries. Objective: The aim of this study is to analyse the effect of lesion eccentricity on the transient flow behaviour in a model of a coronary artery and also to investigate the correlation between Reynolds number (Re) and the eccentricity effect on flow behaviour. Methods: A transient particle image velocimetry (PIV) experiment was implemented in two …silicone based models with 70% diameter stenosis, one with eccentric stenosis and one with concentric stenosis. Results: At different times throughout the flow cycle, the eccentric model was always associated with a greater recirculation zone length, maximum shear strain rate and maximum axial velocity; however, the highest and lowest impacts of eccentricity were on the recirculation zone length and maximum shear strain rate, respectively. Analysis of the results revealed a negative correlation between the Reynolds number (Re) and the eccentricity effect on maximum axial velocity, maximum shear strain rate and recirculation zone length. Conclusions: As Re number increases the eccentricity effect on the flow behavior becomes negligible. Show more

Keywords: Particle image velocimetry, coronary artery, stenosis, eccentricity, Reynolds number

DOI: 10.3233/THC-130736

Citation: Technology and Health Care, vol. 21, no. 4, pp. 357-367, 2013

Authors: Schmitt, K.-U. | Walti, M. | Schälli, O. | Styger, E. | Prud'homme, T.

Article Type: Research Article

Abstract: Background: A simulator of the respiratory system which includes the pleural space is currently lacking. However, such mechanical models are essential to develop and test new medical devices regulating the pressure in the pleural space. Objective: It was the aim of this study to develop a model which mimics the pleural space. The device should be able to represent biomechanical functions of the respiratory system and it is intended for applications in research and development to study pleural space mechanics. The system should allow adjusting parameters to simulate different kinds of breathing. Output parameters such as the pressure …in pleural cavity or the breathing volume should be measured. Methods: A mechanical lung simulator was developed. The chest wall is represented by an elastic shell in which silicone balloons were implemented to mimic the lung tissue. These two components establish a pleural cavity. Pressure sensors were installed to measure pressure in the pleural space and an aeroplethysmograph was positioned above the two lungs to measure flow. The system was assembled and tested under various conditions. Results: Different tests demonstrated that the device is currently capable of simulating breathing volumes up to approx. 1700 ml. Different breathing characteristics including coughing can be simulated. Higher negative pressures especially during deep breathing were observed at the top of the lung because of higher balloon wall (lung) thickness in this area. It was possible to demonstrate the effect of certain changes of the lung tissue such as fibrosis with corresponding pressure recordings confirming known effects of such pathologies. Conclusions: The device allows simulating pressures in the pleural space during breathing at an advanced level and will be of use to develop and validate medical devices under laboratory conditions that control and regulate the pleural space. This represents a significant benefit to improve the development process for devices in this area. Show more

Keywords: Biomechanics, pleural space, respiratory system, mechanical simulator

DOI: 10.3233/THC-130737

Citation: Technology and Health Care, vol. 21, no. 4, pp. 369-378, 2013

Authors: Ezechieli, M. | Siebert, C.H. | Ettinger, M. | Kieffer, O. | Weißkopf, M. | Miltner, O.

Article Type: Research Article

Abstract: Background: The ability to stabilize the body center (core stability) against dynamic movements of the extremities and capability to absorb repetitive loading forces in the trunk play a crucial role in any professional sport specific performance. Objective: The aim our cross sectional level of evidence 3 study was to determine, if athletes of different sport disciplines showed specific trunk strength profiles and if these were different from a control group. Methods: 20 ironman triathletes, 18 amateur volleyball and 18 amateur soccer players were tested for their individual isometric strength of the lumbar spine in three …planes of motion using a standartized test device. Results: The test profile revealed similar strength parameters for extension and lateral flexion to the left in each of the 3 study groups tested. The lateral flexion to the right was significantly stronger than in the control group (soccer > volleyball > triathlon). In all 3 groups, weaknesses were found in the abdominal musculature, showing highly significant differences in flexion and bilateral rotation compared to the control group (p=0.001). Conclusions: Our study shows that sports specific training for triathlon, as well as the team sports soccer and volleyball, does not lead to balanced trunk musculature and core stability. In consequence predisposing injury and muscle dysbalane can trigger pain syndromes. Show more

Keywords: Volleyball, soccer, triathlon, trunk strength, low back pain

DOI: 10.3233/THC-130739

Citation: Technology and Health Care, vol. 21, no. 4, pp. 379-386, 2013

Authors: D'Arcy, Shona | Rapcan, Viliam | Gali, Alessandra | Burke, Nicola | O'Connell, Gloria Crispino | Robertson, Ian H. | Reilly, Richard B.

Article Type: Research Article

Abstract: Background: Cognitive assessments are valuable tools in assessing neurological conditions. They are critical in measuring deficits in cognitive function in an array of neurological disorders and during the ageing process. Automation of cognitive assessments is one way to address the increasing burden on medical resources for an ever increasing ageing population. Objective: This study investigated the suitability of using automated Interactive Voice Response (IVR) technology to deliver a suite of cognitive assessments to older adults using speech as the input modality. Methods: Several clinically valid and gold-standard cognitive assessments were selected for implementation in …the IVR application. The IVR application was designed using human centred design principles to ensure the experience was as user friendly as possible. Sixty one participants completed two IVR assessments and one face to face (FF) assessment with a neuropsychologist. Completion rates for individual tests were inspected to identify those tests that are most suitable for administration via IVR technology. Interclass correlations were calculated to assess the reliability of the automated administration of the cognitive assessments across delivery modes. Results: While all participants successfully completed all automated assessments, variability in the completion rates for different cognitive tests was observed. Statistical analysis found significant interclass correlations for certain cognitive tests between the different modes of administration. Analysis also suggests that an initial FF assessment reduces the variability in cognitive test scores when introducing automation into such an assessment. Conclusion: This study has demonstrated the functional and cognitive reliability of administering specific cognitive tests using an automated, speech driven application. This study has defined the characteristics of existing cognitive tests that are suitable for such an automated delivery system and also informs on the limitations of other cognitive tests for this modality. This study presents recommendations for developing future large scale cognitive assessments. Show more

Keywords: Cognitive assessment, automatic monitoring, speech, Interactive Voice Response

DOI: 10.3233/THC-130740

Citation: Technology and Health Care, vol. 21, no. 4, pp. 387-396, 2013