Vibration-Induced Kinesthetic Illusions and Corticospinal Excitability Changes.

The authors' aim was to investigate the changes of corticospinal excitability during kinesthetic illusions induced by tendon vibration. Motor-evoked potentials in response to transcranial magnetic stimulation were recorded from the vibrated flexor carpi radialis and its antagonist, extensor carpi radialis. The illusions were evoked under vision conditions without feedback for the position of the wrist (open or closed eyes).

Fetal ECG extraction from abdominal signals: a review on suppression of fundamental power line interference component and its harmonics.

Interference of power line (PLI) (fundamental frequency and its harmonics) is usually present in biopotential measurements. Despite all countermeasures, the PLI still corrupts physiological signals, for example, electromyograms (EMG), electroencephalograms (EEG), and electrocardiograms (ECG). When analyzing the fetal ECG (fECG) recorded on the maternal abdomen, the PLI represents a particular strong noise component, being sometimes 10 times greater than the fECG signal, and thus impairing the extraction of any useful information regarding the fetal health state.

A three-component model of the control error in manual tracking of continuous random signals.

Objective: The performance of human operators acting within closed-loop control systems is investigated in a classic tracking task. The dependence of the control error (tracking error) on the parameters display gain, k(display), and input signal frequency bandwidth, f(g), which alter task difficulty and presumably the control delay, is studied with the aim of functionally specifying it via a model.

Background: The human operator as an element of a cascaded human-machine control system (e.

Monitoring the fetal heart rate variations by means of time-variant multivariate analysis.

The analysis of the fetal heart rate (fHR) is important in detecting the fetal distress related with hypoxic episodes, noticed sometimes during the uterine activity, which can severely affect the fetus. Occasional synchrony between the fHR and the maternal heart rate (mHR) was reported and the mHR shows some variations during pregnancy and labor, especially when the contractions are very strong. The current study proposes a new strategy to investigate the relations between the fHR, the mHR and the uterine activity, by applying the time-variant Partial Directed Coherence (tvPDC).

Fetal electrocardiogram enhancement in abdominal recordings: recording setup analysis.

The fetal electrocardiogram (fECG) obtained from the abdominal signals, to monitor the wellbeing of the fetus, is a weak signal, recorded by placing electrodes on the maternal abdomen surface. When recording the abdominal fECG, the main problem is to separate the fECG from the background noise, including the maternal electrocardiogram (mECG) and/or the power line interference (PLI), this leading to an improved fECG signal to noise ratio (SNR). This paper proposes and evaluates three types of recording configurations, having different reference location, and analyzes the performance of each recording setup, based on the corresponding SNRs, quantitatively evaluated.

Dual-tasking: Is manual tapping independent of concurrently executed saccades?

Maintaining both spatial and temporal accuracy of concurrent motor actions is a challenging behavioral requirement in multi-tasking, where possible resource bottlenecks may become apparent when these units are shared between tasks. This study addresses the question of whether periodic self-paced finger movements (tapping) compulsorily interact with concurrently executed saccades, because they share some common neural control pathways. We employed a dual-task paradigm which was previously used to demonstrate strong interference between independent but concurrently conducted bimanual tapping tasks (Wachter, C.

The event synchronous canceller algorithm removes maternal ECG from abdominal signals without affecting the fetal ECG.

Fetal monitoring using abdominally recorded signals (ADS) allows physicians to detect occurring changes in the well-being state of the fetus from the beginning of pregnancy. Mainly based on the fetal electrocardiogram (fECG), it provides the long-term fetal heart rate (fHR) and assessment of the fetal QRS morphology. But the fECG component in ADS is obscured by the maternal ECG (mECG), thus removal of the mECG from ADS improves fECG analysis.

Comparison and evaluation of existing methods for the extraction of low amplitude electrocardiographic signals: a possible approach to transabdominal fetal ECG.

Analysis of the fetal ECG (fECG) allows physicians to detect changes in the well-being state of the fetus. But when assessing the fECG through the abdominal signals (ADS), its very low amplitude causes a problem, as the fECG representation in the ADS is buried in a mixture of other signals with stronger energy. Different methods have been proposed in the past to extract the transabdominal fECG for instantaneous fetal heart rate (fHR) computation; four representatives of them are selected for an accurate comparison of their performance in fECG extraction and in fHR estimation.

Abdominal fetal ECG enhancement by event synchronous canceller.

Abdominal signals (ADS) recorded from pregnant women represent an important tool for monitoring the fetal heart rate (FHR) variability and the well-being state of the fetus, mainly because it has the advantage of being noninvasive. Thus, no risk is given during recording either for the mother or for the fetus, but complex signal processing steps are necessary, mainly due to the presence of the maternal ECG in the ADS, in order to achieve a clean fetal electrocardiogram (fECG). The paper presents an improved application of the Event Synchronous Canceller (ESC) for maternal electrocardiogram (mECG) suppression.

Coordination of a discrete response with periodic finger tapping: additional experimental aspects for a subtle mechanism.

The authors investigated the coordination of periodic right-hand tapping with single stimulus-evoked discrete lefthand taps to check for task interactions and a possible relationship between phase resetting (see tapping literature; e.g., J.

Comparative study of event-synchronous interference cancelling methods.

In case of a periodic disturbing signal as a "noise", special solutions for noise reduction can be applied. In literature, an adaptive noise canceller modification was proposed for this case by Strobach et al. [5] and applied by several other researchers.

Motor timing and more--additional options using advanced registration and evaluation of tapping data.

Motor coordination in multi-tasking situations is relevant to everyday life, since numerous daily activities require the performance of more than one task simultaneously. Investigations into this topic often use dual-task experiments like bimanual tapping, with different instructions for the right and left hands, such as to tap repetitively with the right index finger at a given frequency and to concurrently execute a single tap in response to a go signal with the left index finger. A basic experimental set-up for tapping consists of only a pace signal generator and ground contact sensors such as micro switches for observation of motor action.

A method for locating gradual changes in time series.

A variation to the change-point problem is addressed. The classical problem involves locating abrupt changes in the mean value of a signal. In contrast, a generalisation to gradual changes with constant speed is considered, which frequently occurs in biomedical signal-processing tasks.

Basic aspects concerning the event-synchronous interference canceller.

The adaptive noise canceller (ANC) is a commonly used linear system method for noise reduction in cases where the disturbing noise can be separately recorded (reference signal) and is not correlated with the signal of interest. In case of a periodic disturbing signal, special solutions are described in literature. Problems, however, arise when the propagation of the noise from the source to the recording sensors passes nonlinear structures.