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Objectives : Facial nerve palsy causes blurred vision and ocular discomfort due to deficits in blinking and eye closure. The objective of this study was to determine whether eye-blinks could be elicited by electrical stimulation and whether electrically induced blink would have an effect on the visual acuity and ocular symptoms in patients with acute facial nerve palsy. Methods : The zygomatic branch of the facial nerve of fifteen participants with acute facial nerve palsy was electrically stimulated in order to elicit a blink. In successful cases, the participant proceeded with a two-hour TV watching session in which an electrically induced blink was delivered every 5 seconds. The control condition consisted of an otherwise similar TV watching session without electrically induced blinking. Subjective ocular symptoms were evaluated with a Dry Eye Questionnaire and visual acuity was assessed with a Logarithm of the Minimum Angle of Resolution (LogMAR) chart before and after both sessions. Results : The stimulation produced a blink in 8 participants (53%). The visual acuity in the affected eye decreased during the control session, whereas no significant change occurred during the stimulation session. The ocular symptoms were significantly reduced during the stimulation session. Conclusions : Electrically elicited blink is a promising method for reducing the eye symptoms in individuals with acute facial nerve palsy. [ABSTRACT FROM AUTHOR]

Reanimation of paralysed facial muscles by electrical stimulation has been studied extensively in animal models, but human studies in this field are largely lacking. Twenty-four subjects with a peripheral facial nerve palsy with a median duration of three years were enrolled. We studied activations of four facial muscles with electrical stimulation using surface electrodes. In subjects whose voluntary movement was severely impaired or completely absent, the electrical stimulation produced a movement that was greater in amplitude compared with the voluntary effort in 10 out of 18 subjects in the frontalis muscle, in 5 out of 14 subjects in the zygomaticus major muscle, and in 3 out of 8 subjects in the orbicularis oris muscle. The electrical stimulation produced a stronger blink in 8 subjects out of 22 compared with their spontaneous blinks. The stimulation could produce a better movement even in cases where the muscles were clinically completely paretic, sometimes also in palsies that were several years old, provided that the muscle was not totally denervated. Restoring the function of paralysed facial muscles by electrical stimulation has potential as a therapeutic option in cases where the muscle is clinically paretic but has reinnervation. [ABSTRACT FROM AUTHOR]

Atherosclerosis is a significant cause of mortality in the aged population, and it affects arterial wall properties causing differences in measured arterial pulse wave (PW). In this study, both dynamic arterial blood pressure PWs and blood volume PWs are analyzed. The PWs are recorded noninvasively from multiple measurement points from the upper and lower limbs from 52 healthy (22–90-year-old) volunteers without known cardiovascular diseases. For each signal, various parameters earlier proposed in the literature are computed, and 25 different novel parameters are formed by combining these parameters. The results are evaluated in terms of age and heart rate (HR) dependence of the parameters. In general, the results show that 14 out of 25 tested combined parameters have stronger age dependence than any of the individual parameters. The highest obtained linear correlation coefficients between the age and combined parameter and individual parameter equal to 0.85 (p < 10^-4 ) and 0.79 (p < 10^-4 ), respectively. Most of the combined parameters have also improved discrimination capability when classifying the test subjects into different age groups. This is a promising result for further studies, but indicate that the age dependence of the parameters must be taken into account in further studies with atherosclerotic patients. [ABSTRACT FROM AUTHOR]

Emotional reactions to basic, artificial, yet carefully controllable point-light displays (PLDs) were investigated with ratings of valence, arousal, approachability and dominance. PLDs were varied by movement location (upper and lower) and intensity (10°, 20° and 30° angular change) for angular upward and downward movements. Half of participants (N = 28) were told that PLDs were related to face while to other half nothing was hinted. Results showed that 20° and 30° angle lower location upward movements were rated as significantly more pleasant, relaxing and approachable than corresponding upper location downward movements. Informed participants rated 20° and 30° angle lower movements as significantly more controllable than corresponding upper movements. Results are important from many perspectives, like for understanding human perceptual mechanisms. When using PLDs only a small amount of information needs to be transmitted. This enables low bandwidth requirements. As PLD visualizations are simple, there is no need for high-definition displays. [ABSTRACT FROM AUTHOR]

A wireless body sensor network for arterial pulse wave (PW) measurements is presented and tested with ten subjects. The system is capable of recording both mechanical PW contours with sensors made of a low-cost polypropylene-based material called electromechanical film (EMFi) and volume pulse signal with photoplethysmographic transducers. By using both types of sensors, the PW contours can be recorded from various locations. The system combined with automatic analysis methods enables to easily analyze the PW contours in order to obtain a more comprehensive view on the vascular health. To demonstrate this, two parameters used in literature, reflection index and radial augmentation index were calculated for the test subjects as a function of time. The results show that these parameter values may vary more than 20% in a period of 100 s, which suggests that a large number of PWs should be analyzed before making conclusions based on the calculated indices. In addition, the effects of the static bias force to the mechanical PW signal recorded with the EMFi sensors were studied. The PW signal with the maximum amplitude is obtained when the pressure caused by the static bias force corresponds to the contact pressure between typical systolic and diastolic blood pressures. The EMFi sensors used in the proposed system are a potential low-cost alternative for tonometric sensors in collecting data in the PW analysis for arterial screening. [ABSTRACT FROM PUBLISHER]

Background Although clinical applications such as emergency medicine and prehospital care could benefit from a fast-mounting electroencephalography (EEG) recording system, the lack of specifically designed equipment restricts the use of EEG in these environments. Methods This paper describes the design and testing of a six-channel emergency EEG (emEEG) system with a rapid preparation time intended for use in emergency medicine and prehospital care. The novel system comprises a quick-application cap, a device for recording and transmitting the EEG wirelessly to a computer, and custom software for displaying and streaming the data in real-time to a hospital. Bench testing was conducted, as well as healthy volunteer and patient measurements in three different environments: a hospital EEG laboratory, an intensive care unit, and an ambulance. The EEG data was evaluated by two experienced clinical neurophysiologists and compared with recordings from a commercial system. Results The bench tests demonstrated that the emEEG system's performance is comparable to that of a commercial system while the healthy volunteer and patient measurements confirmed that the system can be applied quickly and that it records quality EEG data in a variety of environments. Furthermore, the recorded data was judged to be of diagnostic quality by two experienced clinical neurophysiologists. Conclusions In the future, the emEEG system may be used to record high-quality EEG data in emergency medicine and during ambulance transportation. Its use could lead to a faster diagnostic, a more accurate treatment, and a shorter recovery time for patients with neurological brain disorders. [ABSTRACT FROM AUTHOR]

The intensity measurement of facial muscle activity can be used in several applications such as human–computer interaction and behavioral science. A new method for the intensity measurement is presented. It is based on a contactless, capacitive measurement of the movements that the facial activity produces. The muscles responsible for raising the eyebrows, lowering the eyebrows, raising the mouth corners, and pulling down the mouth corners are measured simultaneously with the capacitive method and electromyography (EMG) during controlled experiments. Each muscle is activated by 10 participants at three different intensity levels (low, medium, and high), 10 repetitions at each level. The capacitive intensity values are in good agreement with the ones registered with the EMG: average mean absolute errors are between 7% and 12% of the observed intensity range. However, compared with the EMG, the capacitive intensity values are noticed to have offsets that may be partly caused by the measurement itself and partly by the EMG reference. As a result, the measurement may require a calibration for more intensity values than just the maximum. In the capacitive method, it is also required to distinguish between the muscle activations originating from the same facial regions to determine which activation is taking place. This is done with an almost perfect performance by using hierarchical clustering to cluster the intensity values. [ABSTRACT FROM PUBLISHER]

A system for unobtrusive night-time electrocardiogram (EKG) and heart rate variability (HRV) monitoring as well as data analysis methods are presented, comparing bed sheet HR and HRV values with corresponding parameters obtained by a reference measurement. Our system uses eight embroidered textile electrodes attached laterally to a bed sheet for measuring bipolar contact EKG from multiple channels. The electrodes are arranged in a line so that at least two adjacent electrodes make sufficient skin contact. The focus of the signal processing development has been on selecting the best measurement channel for further analysis and minimizing the amount of incorrectly detected R-peaks. The test measurements were performed with four healthy men without previously known cardiac disorders and one who frequently had premature ventricular contractions (ectopic beats). For healthy test subjects, an average of 94.9% heartbeat detection coverage was achieved with the system during 29 measurement nights (in total 213.8 h of data). In most cases, the quality of the signal obtained from bed sheet electrodes is good enough for the computer-assisted cardiac arrhythmia detection. Applications for EKG derived RR-interval data include the calculation of HRV parameters that can be utilized in sleep quality analysis and other wellness-related topics as well as sleep apnoea detection. [ABSTRACT FROM PUBLISHER]

A light-weight, wearable, wireless gaze tracker with integrated selection command source for human‐computer interaction is introduced. The prototype system combines head-mounted, video-based gaze tracking with capacitive facial movement detection that enable multimodal interaction by gaze pointing and making selections with facial gestures. The system is targeted mainly to disabled people with limited mobility over their hands. The hardware was made wireless to remove the need to take off the device when moving away from the computer, and to allow future use in more mobile contexts. The algorithms responsible for determining the eye and head orientations to map gaze direction to on-screen coordinates are presented together with the one to detect movements from the measured capacitance signal. Point-and-click experiments were conducted to assess the performance of the multimodal system. The results show decent performance in laboratory and office conditions. The overall point-and-click accuracy in the multimodal experiments is comparable to the errors in previous research on head-mounted, single modality gaze tracking that does not compensate for changes in head orientation. [ABSTRACT FROM AUTHOR]

Abstract: The methods needed to interrogate passive resonance sensors are studied. A portable impedance measurement unit and the methods to extract a coupling coefficient compensated resonance frequency are presented. The interrogation methods are demonstrated with ECG and pressure measurements. The results show that the quality of the ECG signal measured with a flexible textile coil is sufficient to extract the heart rate. In the case of a pressure sensor, the errors caused by the changes in the inductive coupling were satisfactorily removed by the introduced method. [ABSTRACT FROM AUTHOR]

Control of particle suspensions is needed in several modern industrial processes. A reason for the difficulty in this task has been the lack of a fast and reliable measurement. In this study, we tested the measurement of particle suspension by using a method based on a passive resonance sensor. The relative amounts of dispersing agent and aluminium oxide in the suspension were varied. The studied method yielded signals which depended on the complex permittivity of the suspension. The results indicated that we were able to measure information that can be used as feedback for the suspension preparation process. In addition, the tested instrumentation was simple and robust and thus this method may allow online measurements directly from the industrial processes. [ABSTRACT FROM AUTHOR]

Objectives : Facial nerve palsy causes blurred vision and ocular discomfort due to deficits in blinking and eye closure. The objective of this study was to determine whether eye-blinks could be elicited by electrical stimulation and whether electrically induced blink would have an effect on the visual acuity and ocular symptoms in patients with acute facial nerve palsy. Methods : The zygomatic branch of the facial nerve of fifteen participants with acute facial nerve palsy was electrically stimulated in order to elicit a blink. In successful cases, the participant proceeded with a two-hour TV watching session in which an electrically induced blink was delivered every 5 seconds. The control condition consisted of an otherwise similar TV watching session without electrically induced blinking. Subjective ocular symptoms were evaluated with a Dry Eye Questionnaire and visual acuity was assessed with a Logarithm of the Minimum Angle of Resolution (LogMAR) chart before and after both sessions. Results : The stimulation produced a blink in 8 participants (53%). The visual acuity in the affected eye decreased during the control session, whereas no significant change occurred during the stimulation session. The ocular symptoms were significantly reduced during the stimulation session. Conclusions : Electrically elicited blink is a promising method for reducing the eye symptoms in individuals with acute facial nerve palsy., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Objective: The aim of the study was to show if pulse rise times (PRTs) extracted from photoplethysmographic (PPG) pulse waves (PWs) have an association with peripheral arterial disease (PAD) or its endovascular treatment, percutanoeus transluminal angioplasty (PTA) of the superficial femoral artery., Methods: Lower and upper limb PPG PWs were recorded and analyzed from 24 patients who suffered from PAD. The measurements were conducted before and after the treatment, and one month later by using transmission-mode PPG-probes placed in the index finger and second toe. Ankle-to-brachial pressure index and toe pressures were used as references in clinical patient measurements. PRTs, i.e., the time from the foot point to the peak point of the PW, were extracted from the PWs and compared bilaterally. The results from the PAD patients were also compared with 31 same-aged and 34 younger control subjects., Results: Statistically significant differences were found between the pretreatment PRTs of the treated limb of the PAD patients and the same-aged control subjects ( , Mann-Whitney U-test). The changes in the PRT of the treated lower limb were observed immediately after the PTA ( , Student's t-test), and after one month ( ), whereas the PRTs of the non-treated lower limb and upper limb did not indicate changes between different examinations., Conclusion: Results show that a PRT greater than 240 ms indicates PAD-lesions in the lower limb., Significance: This proof-of-concept study suggests that the PRT could be an effective and easy-to-use indicator for PAD and monitoring the effectiveness of its treatment.

We analyze the changes in upper and lower limb pulse transit times (PTT) caused by peripheral artery disease (PAD) and its treatment with percutaneous transluminal angioplasty (PTA) of the superficial femoral artery. PTTs were extracted from the photoplethysmograms (PPG) recorded from an index finger and 2nd toes. PTTs were defined between the R-peaks of the ECG and different reference points of the PPG: foot and peak points, maxima of 1st and 2nd derivative, and by means of intersecting tangents method. Also the PTTs between the toe and finger pulses were analyzed. Our sample consists of 24 subjects examined before and after the PTA and in 1-month follow-up visit. Also 28 older than 65 years controls having normal ankle-to-brachial pressure index (ABI) and no history in cardiovascular diseases as well as 21 younger subjects were examined. The differences between the groups and pre- and post-treatment phases were analyzed by means of non-parametric statistical tests. The changes in the PTTs of upper limb and non-treated lower limb were negligible. The agreement with the reference values, ABI and toe pressures, was studied by kappa-analysis, resulting in kappa-values of 0.33-0.91. Differences in PTTs were found between pre-treatment state of the treated limb, post-treatment state and the follow-up visit, as well as between the pre-treatment state and controls. If patients' age and systolic blood pressure were taken into consideration, the method of lower limb PTT calculation from the peak point turns out feasible in finding the markers of PAD and monitoring post-treatment vascular remodellation.

Arterial diseases are significant and increasing cause of mortality and morbidity. In this study, we analyze and compare the discrimination capability of different arterial pulse wave (PW) based indices, both earlier proposed and novel ones, for describing the vascular health. The repeatability of the indices is also evaluated. Both volume PWs and dynamic pressure PWs are recorded by using photoplethysmographic and electromechanical film (EMFi) sensors connected to a wireless body sensor network. The study population consists of 82 subjects, 30 atherosclerotic patients, and 52 control subjects. In addition, day-to-day variability of the derived indices is studied with ten test subjects examined on three different days. The results are evaluated in terms of statistical tests and receiver operating characteristic (ROC) curves as well as coefficient of variation (CV) and intraclass correlation coefficient (ICC). Altogether 24 out of the evaluated 40 PW parameters showed statistical differences ( or less) between controls and atherosclerotic patients. Maximum area under curve was 0.88. Most of the indices had ICCs higher than 0.8 and average CVs less than 0.1. The study shows that the amplitude ratios and time intervals between different PW peaks could be a useful additional tool for the detection of atherosclerosis. The results encourage us for further studies in this field. Up to our knowledge, the performance and the repeatability of different PW derived indices have previously not been studied and compared with each other this extensively. Our findings also provide evidence for the utility of PW measurements for the detection of atherosclerotic changes.

Objective: In this study, we propose a method for finding atherosclerotic changes based on the ratios of areas under peripheral arterial pulse wave (PW) contours and analyze its performance., Approach: The PW signals were recorded with force sensors and photoplethysmographic sensors from ankle, wrist, cubital fossa, index finger and second toe from 30 atherosclerotic patients and 52 control subjects. In addition, the day-to-day repeatability of the method was studied with 10 test subjects examined on three different days. The ratios of areas under the PWs were computed and the results were evaluated by means of receiver operating characteristic (ROC) analysis, intra-class correlation (ICC) coefficient and multiple linear regression analysis., Main Results: Areas under ROC curves of 0.802-0.906 were found for different area ratios having statistically significant differences between the atheroslerotic group and control groups. ICCs over 0.80 were found widely for the beat-by-beat analyzed data and over 0.95 for the data based on the averages over different numbers of PWs. Multiple linear regression analysis showed linear dependence between the area ratios and age and the diagnosis of atherosclerosis., Significance: Our findings may facilitate development of novel diagnostic approaches and preventive strategies against cardiovascular disorders. However, further studies are needed to confirm the results. The presented study demonstrates the potential of arterial PW analysis in finding vascular abnormalities.

In this study, we propose and analyze a noninvasive method for detecting the atherosclerotic changes of vasculature based on the analysis of photoplethysmographic (PPG) signals., Methods: the proposed method is called finger-toe (FT)-plot analysis that utilizes both finger and toe PPG signals. For the features extracted from the FT-plots, we implemented different linear discriminant analysis based classifiers and analyzed seven promising ones in detail. We used the signals recorded from altogether 75 test subjects (categorized as 27 atherosclerotic patients and 48 control subjects based on ankle brachial pressure index, symptoms and disease history) in the training, and testing of the method. Besides leave one out cross validation, we tested the method by using training data independent signals recorded with two different PPG devices. The performance of the FT-plot is compared with other indicators related to the risk of cardiovascular diseases., Results: we found an average area under ROC (receiver operating characteristic) curve of [Formula: see text] (mean  ±  standard deviation based on different datasets), sensitivity of [Formula: see text], specificity of [Formula: see text], accuracy of [Formula: see text], performance of [Formula: see text] and positive and negative predictive values of [Formula: see text] and [Formula: see text], respectively, for the different tested classifiers., Conclusions: the study shows that the FT-plot analysis could be a useful additional tool for detecting atherosclerotic changes. Our findings provide evidence for the utility of multi-channel pulse wave measurements and analysis for the detection of atherosclerosis. This may facilitate development of novel early diagnostic approaches and preventive strategies.

Silicon nanowire-based field-effect transistors (SiNW FETs) have demonstrated the ability of ultrasensitive detection of a wide range of biological and chemical targets. The detection is based on the variation of the conductance of a nanowire channel, which is caused by the target substance. This is seen in the voltage-current behavior between the drain and source. Some current, known as leakage current, flows between the gate and drain, and affects the current between the drain and source. Studies have shown that leakage current is frequency dependent. Measurements of such frequency characteristics can provide valuable tools in validating the functionality of the used transistor. The measurements can also be an advantage in developing new detection technologies utilizing SiNW FETs. The frequency-domain responses can be measured by using a commercial sine-sweep-based network analyzer. However, because the analyzer takes a long time, it effectively prevents the development of most practical applications. Another problem with the method is that in order to produce sinusoids the signal generator has to cope with a large number of signal levels. This may become challenging in developing low-cost applications. This paper presents fast, cost-effective frequency-domain methods with which to obtain the responses within seconds. The inverse-repeat binary sequence (IRS) is applied and the admittance spectroscopy between the drain and source is computed through Fourier methods. The methods is verified by experimental measurements from an n-type SiNW FET.

We present a system for measuring ECG signals simultaneously from multiple persons during a group training session. The system transmits the signals to a coordinating computer where heart rate and other parameters are calculated from the signals. The heart rate values can then be shown for example through a video projector on a large display along with individual information about the training intensity.

We are developing an embedded system that measures the force between foot and insole with a low-cost laminated capacitive sensor matrix. The system is intended to guide a hip surgery patient to train the operated leg with a suitable force. In this paper, we present an embedded measurement system, which is able to estimate the total plantar force in real-time and to give instant feedback to a user. We also present a method for compensating the drift of capacitive sensors. A 5-hour long test measurement was made in order to validate the system. According to the preliminary test, the compensation method effectively prevents the drift of the baseline of the force reading.

A miniature wireless node for ECG measurements is presented. The ECG node is designed to be used in various applications including measurement of heart rate during physical exercise and continuous long term measurement of ECG for people assumed having, or being recovering from a cardiac disease. The ECG node is wirelessly connected to a computer using IEEE 802.15.4 based radio protocol. The device sends the measured ECG signal together with additional measurement parameters including battery voltage to the computer, where the ECG signal can be analyzed on-line. The ECG node can operate alone or it can be used as a part of an overall system being designed for monitoring people that are transferred from hospital to home treatment.

A head cap made of fabric for measuring EOG and facial EMG signals is presented. Reusable and easy to use electrodes, embroidered of silver coated thread, are integrated into the cap. A two-way wireless data transmission link operating at license free 2.4 GHz frequency band is used for transferring the 16-bit measurement data, sampled with 1 kHz frequency from six channels at maximum, to the receiver device connected to a PC. Tailored PC software is used for displaying the signals and controlling the measurement parameters. The measurement system is intended for recording facial expressions during human emotion studies but it can also be utilized in computer user interface control. The paper shows preliminary results from EOG and facial EMG measurements.