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| 2. |
- Abualhoul, Mohammad Y., et al.
(författare)
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Free space optical link for biomedical applications
- 2012
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Ingår i: Proceedings of the Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBS. - 1557-170X. - 9781424441198 ; , s. 1667-1670
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Konferensbidrag (refereegranskat)abstract
- Free space optics is an interesting alternative for telemetry with medical implants, due to the high data bandwidths available at optical frequencies. Especially implanted brain-computer interfaces gives rise to large data sets that needs to be transmitted transcutaneous. In this paper we show that it is possible to establish such a link at near-IR wavelengths using a modulated reflector in the implant, thus keeping the laser and the detector on the outside. In addition, we show that it will not only work on short, i.e. touch, distances but also at larger distances, in the range of a meter. We have used an electro absorption modulator to modulate the reflection of an external laser source back towards an external detector. The only part of this system that needs to be implanted is the modulator and drive electronics. The study has been done both by Monte-Carlo simulations of a multi-layer model of a rat skull, and with an experiment demonstrating the feasibility of the link when transmitted through biological tissue. The results show that it is possible to establish a transcutaneous link with an external laser source and light detector, and an internal modulated reflector.
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| 3. |
- Ahkami, Bahareh, 1994, et al.
(författare)
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Probability-Based Rejection of Decoding Output Improves the Accuracy of Locomotion Detection During Gait
- 2023
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Ingår i: Proceedings of the Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBS. - 1557-170X.
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Konferensbidrag (refereegranskat)abstract
- Prosthetic users need reliable control over their assistive devices to regain autonomy and independence, particularly for locomotion tasks. Despite the potential for myoelectric signals to reflect the users' intentions more accurately than external sensors, current motorized prosthetic legs fail to utilize these signals, thus hindering natural control. A reason for this challenge could be the insufficient accuracy of locomotion detection when using muscle signals in activities outside the laboratory, which may be due to factors such as suboptimal signal recording conditions or inaccurate control algorithms.This study aims to improve the accuracy of detecting locomotion during gait by utilizing classification post-processing techniques such as Linear Discriminant Analysis with rejection thresholds. We utilized a pre-recorded dataset of electromyography, inertial measurement unit sensor, and pressure sensor recordings from 21 able-bodied participants to evaluate our approach. The data was recorded while participants were ambulating between various surfaces, including level ground walking, stairs, and ramps. The results of this study show an average improvement of 3% in accuracy in comparison with using no post-processing (p-value < 0.05). Participants with lower classification accuracy profited more from the algorithm and showed greater improvement, up to 8% in certain cases. This research highlights the potential of classification post-processing methods to enhance the accuracy of locomotion detection for improved prosthetic control algorithms when using electromyogram signals.Clinical Relevance-Decoding of locomotion intent can be improved using post-processing techniques thus resulting in a more reliable control of lower limb prostheses.
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| 4. |
- Alcaraz Martinez, Raul, et al.
(författare)
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Application of frequency and sample entropy to discriminate long-term recordings of paroxysmal and persistent atrial fibrillation
- 2010
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Ingår i: Engineering in Medicine and Biology Society (EMBC), 2010 Annual International Conference of the IEEE. - 1557-170X. - 9781424441235 ; , s. 4558-4561
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Konferensbidrag (refereegranskat)abstract
- Atrial fibrillation (AF) is the most common arrhythmia in clinical practice. At an early stage of the disease, AF may terminate spontaneously and is then referred to as paroxysmal AF. On the other hand, when external intervention is required for the arrhythmia to terminate, it is referred to as persistent AF. In this work, a method to discriminate between paroxysmal and persistent AF in the long-term ECGs is presented. The dominant frequency as well as the organization of the atrial activity are employed to characterize AF. The dominant atrial frequency (DAF) is estimated using hidden Markov model based frequency tracking, and organization is estimated by the sample entropy of the main atrial wave (MAW) and the first two harmonics, respectively. Long-term variations in DAF and organization from 50 ECG recordings were evaluated, showing that episodes of paroxysmal AF were consistently associated with lower DAF and organization of the MAW and the harmonics, than was persistent AF. Discrimination of paroxysmal and persistent AF resulted in classification rates of 84.1±26.1%, thus suggesting that it possible to discriminate between paroxysmal and persistent AF in patients without previously known AF history.
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| 5. |
- Alipoor, Mohammad, 1983, et al.
(författare)
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On High Order Tensor-based Diffusivity Profile Estimation
- 2013
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Ingår i: Proceedings of the Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBS. - 1557-170X. - 9781457702167 ; , s. 93-96, s. 4-
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Konferensbidrag (refereegranskat)abstract
- Diffusion weighted magnetic resonance imaging (dMRI) is used to measure, in vivo, the self-diffusion of water molecules in biological tissues. High order tensors (HOTs) are used to model the apparent diffusion coefficient (ADC) profile at each voxel from the dMRI data. In this paper we propose: (i) A new method for estimating HOTs from dMRI data based on weighted least squares (WLS) optimization; and (ii) A new expression for computing the fractional anisotropy from a HOT that does not suffer from singularities and spurious zeros. We also present an empirical evaluation of the proposed method relative to the two existing methods based on both synthetic and real human brain dMRI data. The results show that the proposed method yields more accurate estimation than the competing methods.
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| 6. |
- Anderson, Rachele, et al.
(författare)
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Insights on Spectral Measures for HRV Based on a Novel Approach for Data Acquisition
- 2018
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Ingår i: Annual International Conference of the IEEE Engineering in Medicine and Biology - Proceedings. - 1557-170X. ; 2018, s. 510-513
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, we present new insights on classical spectral measures for heart rate variability (HRV), based on a novel method for HRV acquisition. A dynamic breathing task, where the test participants are asked to breathe following a metronome with slowly increasing frequency, allows for the acquisition of respiratory-related HRV-data covering the frequency range in which adults breathe in different everyday situations. We discuss how the use of a time-frequency representation, e.g. the spectrogram or the Wigner-Ville distribution, should be preferred to the traditional use of the periodogram, due to the non-stationarity of the data. We argue that this approach can highlight the correlation of spectral measures such as low-frequency and high-frequency HRV with relevant factors as age, gender and Body-Mass-Index, thanks to the improved quality of the spectral measures.
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| 7. |
- Behjat, Hamid, et al.
(författare)
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Canonical cerebellar graph wavelets and their application to fMRI activation mapping
- 2014
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Ingår i: [Host publication title missing]. - 1557-170X. ; , s. 1039-1042
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Konferensbidrag (refereegranskat)abstract
- Wavelet-based statistical parametric mapping (WSPM) is an extension of the classical approach in fMRI activation mapping that combines wavelet processing with voxel-wise statistical testing. We recently showed how WSPM, using graph wavelets tailored to the full gray-matter (GM) structure of each individual’s brain, can improve brain activity detection compared to using the classical wavelets that are only suited for the Euclidian grid. However, in order to perform analysis on a subject-invariant graph, canonical graph wavelets should be designed in normalized brain space. We here introduce an approach to define a fixed template graph of the cerebellum, an essential component of the brain, using the SUIT cerebellar template. We construct a corresponding set of canonical cerebellar graph wavelets, and adopt them in the analysis of both synthetic and real data. Compared to classical SPM, WSPM using cerebellar graph wavelets shows superior type-I error control, an empirical higher sensitivity on real data, as well as the potential to capture subtle patterns of cerebellar activity.
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| 8. |
- Brown, Shannon, et al.
(författare)
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Intarsia-sensorized band and textrodes for real-time myoelectric pattern recognition
- 2016
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Ingår i: Engineering in Medicine and Biology Society (EMBC), 2016 IEEE 38th Annual International Conference of the. - : Institute of Electrical and Electronics Engineers (IEEE). - 1557-170X. - 9781457702204 ; , s. 6074-6077
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Konferensbidrag (refereegranskat)abstract
- Surface Electromyography (sEMG) has applications in prosthetics, diagnostics and neuromuscular rehabilitation. Self-adhesive Ag/AgCl are the electrodes preferentially used to capture sEMG in short-term studies, however their long-term application is limited. In this study we designed and evaluated a fully integrated smart textile band with electrical connecting tracks knitted with intarsia techniques and knitted textile electrodes. Real-time myoelectric pattern recognition for motor volition and signal-to-noise ratio (SNR) were used to compare its sensing performance versus the conventional Ag-AgCl electrodes. After a comprehending measurement and performance comparison of the sEMG recordings, no significant differences were found between the textile and the Ag-AgCl electrodes in SNR and prediction accuracy obtained from pattern recognition classifiers.
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| 9. |
- Caltenco, Héctor, et al.
(författare)
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TongueWise : tongue-computer interface software for people with tetraplegia
- 2010
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Ingår i: International Conference of the IEEE Engineering in Medicine and Biology Society. - 1557-170X. - 9781424441235 ; 32, s. 4534-4537
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Konferensbidrag (refereegranskat)abstract
- Many computer interfaces and assistive devices for people with motor disabilities limit the input dimensionality from user to system, in many cases leading to single switch interfaces where the user can only press one button. This can, either limit the level of direct access to the functionalities of the operating system, or slow down speed of interaction. In this paper we present TongueWise: a software developed for a tongue computer interface that can be activated with the tip of the tongue and that provides direct input that covers most of the standard keyboard and mouse commands.
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| 10. |
- Candefjord, Stefan, 1981, et al.
(författare)
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Microwave technology for localization of traumatic intracranial bleedings—a numerical simulation study
- 2013
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Ingår i: Proceedings of the Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBS. - 1557-170X. - 9781457702167 ; , s. 1948-1951
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Konferensbidrag (refereegranskat)abstract
- Traumatic brain injury (TBI) is a major public health problem worldwide. Intracranial bleedings represents the most serious complication of TBI and need to be surgically evacuated promptly to save lives and mitigate injury. Microwave technology (MWT) is promising as a complement to computed tomography (CT) to be used in road and air ambulances for early detection of intracranial bleedings. In this study, we perform numerical simulations to investigate if a classification algorithm based on singular value decomposition can distinguish between bleedings at different positions adjacent to the skull bone for a similar but simplified problem. The classification accuracy is 94-100% for all classes, a result that encourages us to pursue our efforts with MWT for more realistic scenarios. This indicates that MWT has potential for localizing a detected bleeding, which would increase the diagnostic value of this technique.
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