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We here studied the efficacy of wide-band frequency spectra (WBFS) features using multi-taper (MT) spectral analysis in application to motor imagery based Brain Computer Interfaces. We acquired motor imagery task related human scalp electroencephalography (EEG) signals for left vs. right hand movements using 3 different pairs of visual arrow cues. Left vs. right movement imagery discrimination was...
Our aim was to explore time-varying coherence values versus spacing and referencing of electrode contacts in thalamic level from human encephalographic (EEG) data. Data has been acquired during induction of propofol anesthesia until burst-suppression level in scalp EEG. Results are shown from coherence analysis applied to EEG signals from selected depth electrode contacts pair-wise of three subjects...
A differential, time-invariant, surface electromyogram (sEMG) model has been implemented. While it is based on existing EMG models, the novelty of this implementation is that it assigns more accurate distributions of variables to create realistic motor unit (MU) characteristics. Variables such as muscle fibre conduction velocity, jitter (the change in the interpulse interval between subsequent action...
This study presents a preliminary analysis of the relationship between electroencephalographic (EEG) and electrocorticographic (ECoG) event-related potentials (ERPs) recorded from from a single patient using a brain-computer interface (BCI) speller. The patient had medically intractable epilepsy and underwent temporary placement of an intracranial ECoG grid electrode array to localize seizure foci...
We introduce finite rate of innovation (FRI) based spike acquisition, a new approach to the sampling of action potentials. Drawing from emerging theory on sampling FRI signals, our process aims to acquire the precise shape and timing of spikes from electrodes with single or multiunit spiking activity using sampling rates of 1000 Hz or less. The key insight is that action potentials are essentially...
The aim of this paper is to demonstrate a highly integrated architecture for direct Analog-to-QRS detection for ultra low power single chip implementation suitable for long term wearable monitoring. A novel variable input-feature correlated asynchronous sampling technique is proposed for direct sampling-cum-data compression at the ECG electrodes with embedded mixed-signal algorithm for direct recognition...
In this paper, we investigated the quality of ElectroEncephaloGraphic (EEG) signals during performing physical movements. By using a portable EEG device, the Steady-State Visual Evoked Potential (SSVEP) was recorded on parietal and occipital locations. The SSVEP induced by flickering stimuli was successfully observed in the self-paced mimic walking conditions as well as in the sitting conditions....
Graphical models are powerful tools to infer statistical relationships between simultaneously observed random variables. Here, we used Dynamic Bayesian Networks (DBN) to infer causal relationships between simultaneously recorded neurons in the rat somatosensory (barrel) cortex in response to whisker stimulation. DBNs attempt to explain the activity of the observed neurons by searching for the best...
Most previous studies of electromyography (EMG) pattern recognition control of multifunctional myoelectric prostheses adopted a conventional sampling rate that is commonly used in EMG research fields. However, it is unknown whether using a lower sampling rate in EMG acquisition still preserves sufficient neural control information for accurate classification of user movement intents. This study investigated...
Event-related potentials (ERPs) are one of the most informative and dynamic methods of monitoring cognitive processes, which are widely used in clinical research to deal a variety of psychiatric and neurological disorders as attention-deficit/hyperactivity disorder (ADHD). This work proposes an extraction and selection methodology for discriminating between normal and pathological patients with ADHD...
CardioBip (CB) is a hand-held patient-activated device for recording and wireless transmission of reconstructed 12-lead ECG (12CB) based on patient specific matrices. It has 5 contact points: 3 precordial and 2 on the device top serving as limb leads when touched by index fingers. To determine whether CB could be used to monitor coronary disease (CAD) patients, we compared 12CB to simultaneous 12-lead...
T-wave alternans (TWA) is a cardiac phenomenon associated with the mechanisms leading to sudden cardiac death. In this work, we evaluate different source separation techniques for multilead detection of TWA in the electrocardiogram (ECG). Two periodicity-based techniques - periodic component analysis (πCA) and the newly proposed spectral ratio maximization (SRM) - are compared to two independence-based...
Arrhythmia is a major health problem and is the subject of much research and computational modeling. The impact of this research has been limited by the availability of human data and by difficulties in its translation to clinical practice. This paper describes an expert system for analysis of cardiac electrogram signals, detecting local activation and repolarization times using heuristic algorithms...
Exploration into electrical stimulation of the retina has thus far focussed primarily upon the development of prostheses targeted at one of two sites of intervention - the epi- and sub-retinal surfaces. These two approaches have sound, logical merit owing to their proximity to retinal neurons and their potential to deliver stimuli via the surviving retinal neural networks respectively. There is increasing...
Wireless sensor networks have become increasingly common in everyday applications due to decreasing technology costs and improved product performance, robustness and extensibility. Wearable physiological monitoring systems have been utilized in a variety of studies, particularly those investigating ECG or EMG during human movement or sleep monitoring. These systems require extensive validation to...
We studied the dynamical pattern of transmission involved in the information processing during cognitive experiments engaging working memory. The ensemble averaging approach was used to fit a multichannel autoregressive model to the EEG signals recorded during the transitive reasoning task. The short-time directed transfer function was estimated for finding dynamical patterns of functional connectivity...
Propagation of action potentials (APs) through an adequate number of uterine muscle cells induces contraction of the uterus. Monitoring uterine contractions, as the first sign of labor, can provide important information on the course of pregnancy and delivery. Unfortunately, current monitoring methods are affected by serious limitations. The electrohysterogram (EHG), which is the noninvasive recording...
Fetal Heart Rate (FHR) monitoring gives important information about the fetus health state during pregnancy. This paper presents a new prototype for remote fetal monitoring. The device will allow to monitor FHR in a domiciliary context and to send fetal ECG traces to a hospital facility, where clinicians can interpret them. In this way the mother could receive prompt feedback about fetal wellbeing...
The kinematics of hand movement have been reported to be encoded in neural activities recorded at the primary motor cortex accompanying or immediately preceding the movement. In our earlier study, we demonstrated that the speed of imagined hand movements can be represented in the noninvasive EEG recordings and continuously decoded. In the present work, we aimed to systematically examine the spectral-temporal...
Several techniques have been used to improve the signal-to-noise ratio to increase the detection rate of Event Related Potentials (ERPs). This work investigates the application of spatial filtering based on principal component analysis (PCA) to detect ERP due to left-hand index finger movement imagination. The EEG signals were recorded of central derivations (C4, C2, Cz, C1 and C3), positioned according...
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