A novel smartphone app for blood pressure measurement: a proof-of-concept study against an arterial catheter.

Smartphones may provide a highly available access to simplified hypertension screening in environments with limited health care resources. Most studies involving smartphone blood pressure (BP) apps have focused on validation in static conditions without taking into account intraindividual BP variations. We report here the first experimental evidence of smartphone-derived BP estimation compared to an arterial catheter in a highly dynamic context such as induction of general anesthesia. We tested a smartphone app (OptiBP) on 121 patients requiring general anesthesia and invasive BP monitoring. For each patient, ten 1-min segments aligned in time with ten smartphone recordings were extracted from the continuous invasive BP. A total of 1152 recordings from 119 patients were analyzed. After exclusion of 2 subjects and rejection of 565 recordings due to BP estimation not generated by the app, we retained 565 recordings from 109 patients (acceptance rate 51.1%). Concordance rate (CR) and angular CR demonstrated values of more than 90% for systolic (SBP), diastolic (DBP) and mean (MBP) BP. Error grid analysis showed that 98% of measurement pairs were in no- or low-risk zones for SBP and MBP, of which more than 89% in the no-risk zone. Evaluation of accuracy and precision [bias ± standard deviation (95% limits of agreement)] between the app and the invasive BP was 0.0 ± 7.5 mmHg [- 14.9, 14.8], 0.1 ± 2.9 mmHg [- 5.5, 5.7], and 0.1 ± 4.2 mmHg [- 8.3, 8.4] for SBP, DBP and MBP respectively. To the best of our knowledge, this is the first time a smartphone app was compared to an invasive BP reference. Its trending ability was investigated in highly dynamic conditions, demonstrating high concordance and accuracy. Our study could lead the way for mobile devices to leverage the measurement of BP and management of hypertension.

Towards VO2 monitoring: Validation of a heart rate based algorithm.

This article presents and validates a novel algorithm for the continuous monitoring of the VO2 during exercise. The algorithm relies on instantaneous HR measurements to provide a continuous estimation, and can be integrated in a wearable device (e.g., smartwatch, sensor patch). It can be customized by user's main anthropomorphic parameters and automatically learns from newly incoming data recalibrating itself if needed. The system is evaluated against a database of 14 healthy subjects performing various maximal endurance tests. The proposed method provides a VO2 estimation with average RMSE of 4.63 ml/kg/min.

An autonomous medical monitoring system: Validation on arrhythmia detection.

In this paper, we present a generic platform for autonomous medical monitoring and diagnostics. We validated the platform in the context of arrhythmia detection with publicly available databases. The big advantage of this platform is its capacity to deal with various types of physiological signals. Many pre-processing steps are performed to bring the input information into a uniform state that will be explored by a machine learning algorithm. Since this block plays a crucial role in the entire processing pipeline, three different methods were evaluated for detection and classification of anomalies. The results presented in this work are validated on cardiac beats, where the highest accuracy was obtained on the classification of normal beats (94%). On the other hand, atrial fibrillation and premature ventricular contraction beats were classified with an accuracy of 78%.

Non-invasive monitoring of pulmonary artery pressure at the bedside.

Current solutions for the monitoring of pulmonary artery pressure (PAP) in patients suffering from pulmonary hypertension are limited to invasive means. Non-invasive alternatives, such as Doppler echocardiography, are incompatible with continuous monitoring due to their dependency on qualified personnel to perform the measurements. In the present study, a novel non-invasive and unsupervised approach based on the use of electrical impedance tomography (EIT) is presented. The approach was evaluated in three healthy subjects undergoing hypoxia-induced variations in PAP. A timing parameter - physiologically linked to the PAP via the so-called pulse wave velocity principle - was automatically extracted from the EIT data. Reference systolic PAP estimates were obtained by echocardiography. Strong correlation scores (r e [0.844, 0.990]) were found between the EIT-derived parameter and the reference PAP, thereby suggesting the validity of the proposed approach. If confirmed in larger datasets, these findings could open the way for a new branch of fully non-invasive hemodynamic monitors for patients with pulmonary hypertension.

Real-time monitoring of swimming performance.

This article presents the performance results of a novel algorithm for swimming analysis in real-time within a low-power wrist-worn device. The estimated parameters are: lap count, stroke count, time in lap, total swimming time, pace/speed per lap, total swam distance, and swimming efficiency (SWOLF). In addition, several swimming styles are automatically detected. Results were obtained using a database composed of 13 different swimmers spanning 646 laps and 858.78 min of total swam time. The final precision achieved in lap detection ranges between 99.7% and 100%, and the classification of the different swimming styles reached a sensitivity and specificity above 98%. We demonstrate that a swimmers performance can be fully analyzed with the smart bracelet containing the novel algorithm. The presented algorithm has been licensed to ICON Health & Fitness Inc. for their line of wearables under the brand iFit.

Physical activity in youth with osteogenesis imperfecta type I.

INTRODUCTION: Individuals with Osteogenesis Imperfecta (OI) type I often show muscular weakness. However, it is unclear whether muscular weakness is a consequence of physical inactivity or a result of the disease itself. The aim was to assess muscle function in youth with OI type I and evaluate physical activity (PA). METHODS: Fourteen children with OI type I (mean age [SD]: 12.75 [4.62] years) were compared to 14 age- and gender-matched controls (mean age [SD]: 12.75 [4.59] years). Muscle force and power were determined through mechanography. PA and daily energy expenditure were measured with an accelerometer and a questionnaire. RESULTS: Compared to controls, children with OI type I had lower muscle force and power. OI type I children were as active as their healthy counterparts. CONCLUSIONS: Children and adolescents with OI type I and their healthy counterparts did not reached daily recommendations of PA. Given their muscle function deficit, youth with OI type I would benefit to reach these recommendations to prevent precocious effect of aging on muscles.

Accurate walking and running speed estimation using wrist inertial data.

In this work, we present an accelerometry-based device for robust running speed estimation integrated into a watch-like device. The estimation is based on inertial data processing, which consists in applying a leg-and-arm dynamic motion model to 3D accelerometer signals. This motion model requires a calibration procedure that can be done either on a known distance or on a constant speed period. The protocol includes walking and running speeds between 1.8km/h and 19.8km/h. Preliminary results based on eleven subjects are characterized by unbiased estimations with 2(nd) and 3(rd) quartiles of the relative error dispersion in the interval ±5%. These results are comparable to accuracies obtained with classical foot pod devices.

Physical activity profiling: Activity-specific step counting and energy expenditure models using 3D wrist acceleration.

In this paper, we present the evaluation of a new physical activity profiling system embedded in a wrist-located device. We propose a step counting and an energy expenditure (EE) method, and evaluate their accuracy against gold standard references. To this end, we used an actimetry sensor on the waist and an indirect calorimetry monitoring device on a population of 13 subjects to obtain step count and metabolic equivalent task (kcal/kg/h) referenced values. The subjects followed a protocol that spanned a given set of activities (lying, standing, walking, running) at a wide range of intensities. The performance of the EE model was characterized by a root-mean-square error (RMSE) of 1.22±0.34kcal/min, and step-count model at regular walking/running speeds by 0.71±0.06step/10sec.

Impact of muscle activation on ranges of motion during active elbow movement in children with spastic hemiplegic cerebral palsy.

BACKGROUND: Children with spastic hemiplegic cerebral palsy are restricted in their daily activities due to limited active ranges of motion of their involved upper limb, specifically at the elbow. Their impaired muscles are frequently targeted by anti-spastic treatments that reduce muscle tone. But these treatments do not necessarily improve the limb function. There is a lack of comprehensive knowledge of the quantitative relations between muscle activation and joint active ranges of motion. Consequently, the objective of this study is to quantify the impact of muscle activation on the elbow active ranges of motion. METHODS: During voluntary elbow pronation/supination and extension/flexion movements, kinematic and electromyographic measurements were collected from the involved upper limb of 15 children with spastic hemiplegic cerebral palsy (mean age=8.7 years, standard deviation=2.2) and the dominant upper limb of 15 age-matched children who are typically developing. Representative indicators of the muscle activation, such as the muscle co-activation, were extracted from the electromyographic measurements. FINDINGS: Muscle co-activation in the involved upper limb accounted for 78% and 59% of the explained variance of the supination and extension limited active ranges of motion respectively. The agonist and antagonist muscle activations were both longer in the involved upper limb. INTERPRETATIONS: This study succeeded in quantifying the impact of longer antagonist muscle activation on decreased elbow active ranges of motion in children with spastic hemiplegic cerebral palsy. Longer agonist muscle activation suggests that strengthening agonist muscles could increase the extension and supination ranges of motion, which constitutes a perspective of future clinical studies.

Validity of an accelerometer as a vertical ground reaction force measuring device in healthy children and adolescents and in children and adolescents with osteogenesis imperfecta type I.

INTRODUCTION: Vertical ground reaction forces (vGRFs) are closely related to bone strength and development. It is therefore relevant to assess these forces in bone disorders accompanied with muscle weakness such as in osteogenesis imperfecta type I (OI type I). The purpose of the present study was to assess the validity of vGRFs derived from an accelerometer. METHODS: Fourteen children and adolescents with a diagnosis of OI type I (age range: 7 to 21; mean age [SD]: 14.1 [4.8] years; 5 males) and fourteen healthy controls (age range: 6 to 21; mean age [SD]: 12.5 [4.2] years; 5 males) performed three repetitions of five different jump and rise tests on a ground reaction force plate. Jumps and rises outcomes were measured simultaneously with the ground reaction force plate and an accelerometer. RESULTS: Pearson correlation coefficients were over 0.96 (p<0.001) for the five tests. The limits of agreement represented between 17 and 31% of the average peak force measured by both devices. The accelerometer is a promising tool to assess ground reaction forces in everyday life settings and has been shown to be sufficiently sensitive to detect muscular weakness in children and adolescent with OI type I.

Agreement between vertical ground reaction force and ground reaction force vector in five common clinical tests.

Mechanography is an innovative method to evaluate lower-limb dynamic muscle function. This technique is generally performed on force platforms that measure only the vertical component of ground reaction force (GRF). The underlying assumption is that medio-lateral and antero-posterior forces do not contribute significantly to the GRF in jumping and rising tests. The goal of this study was to establish the validity of this assumption. Fifteen healthy adults (mean age [SD]: 30 [11] years; mean height [SD]: 1.68 [0.12] m; mean body mass: 70 [18] kg) performed three repetitions of five different tests in the following order: multiple two-legged hopping, multiple one-legged hopping, single two-legged jump, heel-rise test and chair-rise test. An excellent agreement was found between peak GRF and peak vertical GRF. In each of the five tests, peak vertical GRF represented more than 99% of peak GRF. Moreover, the limits of agreement ranged between 0.05% (multiple two-legged hopping test) and 0.4% (heel-rise test) of the averaged peak force measurements. Therefore measuring only the vertical component of ground reaction force in healthy participants is appropriate for the five tests used in the present study.

Gait analysis using a force-measuring gangway: intrasession repeatability in healthy adults.

OBJECTIVES: The goal of the present study was to determine the repeatability of gait parameters measured by a force plate gait analysis system (Leonardo Mechanograph® GW). METHODS: Fifteen healthy adult participants walked at a self-selected speed on a 10 m long walkway. Vertical ground reaction forces were measured in the central 6 m of the walkway. Each participant performed three trials while walking barefoot and three trials while wearing shoes, each trial consisting of three 10 m walks. RESULTS: There were minimal differences between trials at each condition. All primary force, time, distance and velocity parameters had intraclass correlation coefficients above 0.90 and coefficients of variation in the order of 2% to 4%. Compared to walking barefoot, walking in shoes resulted in 14% lower maximal vertical ground reaction force, 5% longer step length and 2% higher average velocity and caused less lateral translation of the center of force. CONCLUSIONS: In this group of healthy adults, gait analysis with a force plate system produced repeatable intra-day results. The observation that barefoot and shod walking yield different results indicates that it is important to standardize test conditions.

Sensorimotor adaptation in Parkinson's disease: evidence for a dopamine dependent remapping disturbance.

Sensorimotor adaptation is thought to involve a remapping of the kinematic and kinetic parameters associated with movements performed within a changing environment. Patients with Parkinson's disease (PD) are known to be affected on this type of learning process, although the specific role of dopamine depletion in these deficits has not yet been elucidated. The present study was an attempt to clarify whether dopamine depletion in PD may directly affect the capacity to internally reorganize the visuomotor remapping of a distorted environment. Fourteen PD patients were tested twice, while they were treated and while they were withdrawn from their regular levodopa treatment. Fourteen control subjects were also enrolled and tested twice. Two parallel forms of the Computed Mirror Pointing Task (CMPT), requiring making a reaching movement in a visually transformed environment (mirror inversion), were administered to each participant. Each of them had to perform 40 trials at each of the 2 testing sessions. At each trial, sensorimotor adaptation was evaluated by the initial direction angle (IDA), which reflects the direction of movement before any visually guided readjustment. Results revealed no IDA difference at baseline, between control subject and PD patients, whether they were treated or not. In all group, IDA values at that time were large, reflecting a tendency to make movements according to the real life visuomotor mapping (based on the natural direct vision). However, striking differences appeared during sensorimotor learning, in that IDA reduction along trials was poorer in patient not treated with levodopa than both control subjects and the same PD patient treated with levodopa. No difference was observed between the treated PD patients and control subjects. Given that IDA is thought to reflect the internal representation of the visuomotor mapping, it is concluded that dopamine depletion in PD would affects sensorimotor adaptation, in that it facilitates old and poorly adapted movements (real life mapping), instead of new and more adapted ones (mirror transformed mapping).

Postural control anomalies in children with Tourette syndrome.

The goal of the present study was to determine whether postural control is affected in Gilles-de-la-Tourette syndrome (TS). Center of pressure (COP) displacements were recorded in children with TS and unaffected siblings in three conditions using a force platform: (1) Eyes-Open, (2) Eyes-Closed, (3) One-Leg standing with eyes open. The COP range and velocity were higher in children with TS than in unaffected siblings in all conditions. These differences could not be attributed to age, present tic severity, comorbidities (hyperactivity and compulsions) or medication. The data suggest that sub-clinical postural control anomalies are present in TS.

Sensorimotor mapping affects movement correction deficits in early Huntington's disease.

Huntington's disease (HD) is associated with early voluntary movement problems linked to striatal dysfunction. In pointing movements, HD increases the irregularity of the terminal part of movements, suggesting a dysfunction in error feedback control. We tested this hypothesis in movements requiring continuous feedback control. Patients in the early stages of HD and controls traced as fast and accurately as possible circles within a 5-mm annulus on a digitizing tablet when visual feedback of the hand and the circle was direct or indirect (through a monitor). Patients deviated more often from the annulus and showed larger corrections toward the circle than controls when using indirect visual feedback but not with direct visual feedback. When velocity requirements were removed, patients showed little change in these control problems. These results suggest that HD does not affect error feedback control in all movements and that the striatal contribution to voluntary movement is sensitive to sensorimotor mapping.

Immunization of broiler chicks by in ovo injection of infective stages of Eimeria.

Immunization of chickens by in ovo injection of infective stages of 5 species of Eimeria was investigated. Fertile Hubbard x Petersen broiler chicken eggs were injected through the air cell on d 18 of incubation with oocysts of E. acervulina, E. maxima, E. mitis, E. praecox, or E. brunetti. Injected doses of all species ranged from 1 x 10(2) to 1 x 10(6) sporulated oocysts per egg. Chicks receiving oocysts in ovo shed oocysts posthatch. After 2 wk in wire-floored cages, birds were given a challenge infection with the homologous Eimeria species. Chicks immunized by in ovo injection of oocysts had significantly reduced lesion scores, improved weight gain, or reduced oocyst output compared with their nonimmunized counterparts. In additional studies, eggs were injected with 1 x 10(5) sporozoites of E. tenella, E. maxima, or E. acervulina per egg. Sporozoites of E. acervulina were not infective for chick embryos when administered in phosphate-buffered saline, but if sporozoites were suspended in tissue culture medium when injected in ovo, hatched chicks shed oocysts with peak output occurring 3 to 4 d posthatch. Sporozoites of E. maxima and E. tenella were infective for 18-d-old embryos regardless of the vehicle. The results demonstrate that immunization of broiler chickens against several species of coccidia by in ovo injection of oocysts is feasible. The infectivity of sporozoites for 18-d-old chick embryos varied depending on the species of Eimeria and the vehicle in which the sporozoites were suspended prior to injection.

Expression of CCAAT-binding factor antisense transcripts in reproductive tissues affects plant fertility.

We have previously isolated a CCAAT-binding factor B subunit gene ( BnCBF-B) from Brassica napus that is widely expressed in different plant tissues and whose role is still unknown. To investigate the importance of this transcription factor subunit in plant reproductive tissues, we targeted antisense BnCBF-B transcripts to the tapetum of transgenic B. napus plants. Of the 24 independent transformants, 13 yielded reduced quantities of viable pollen, of which five were unable to produce the elongated siliques indicative of normal seed set. The decrease in pollen viability probably resulted from the precocious degeneration of the tapetal cell layer observed in these plants. Surprisingly, the male-sterile phenotype was also accompanied by a decrease in female fertility, which could be due to the expression of the antisense BnCBF-B transcripts in the female reproductive structures of the transgenic plants. These results suggest that the BnCBF-B gene plays a critical non-redundant role in plant reproductive tissues.

Visual deficits in a patient with 'kaleidoscopic disintegration of the visual world'.

We describe psychophysical, neuropsychological and neuro-ophthalmological studies of visual abilities in a patient who, following a right hemisphere stroke, had difficulty in combining parts of objects into a whole and in reading. Strikingly, her perceptual problems were accentuated when the objects moved or when she moved. Formal testing showed that her main deficits were in depth perception, various tasks of motion and object recognition of degraded stimuli. But low-level detection and discrimination of form and color were normal. Despite her deficits in visual motion and degraded static-object recognition, her visual recognition of 'biological motion' stimuli was normal. Structural magnetic resonance imaging revealed an infarct in the ventro-medial occipito-temporal region, extending ventro-laterally and leading to a 'kaleidoscopic disintegration of visible objects'.

Effect of inoculum composition and low KCl supplementation on the biological and rheological stability of an immobilized-cell system for mixed mesophilic lactic starter production.

Two strains of Lactococcus lactis subsp. lactis (L. lactis KB and KBP) and one of L. lactis subsp. lactis biovar. diacetylactis (L. diacetylactis MD) were immobilized separately in kappa-carrageenan-locust bean gum gel beads. Continuous fermentations were carried out in supplemented whey permeate in a 1-L pH-controlled stirred tank reactor inoculated with a 30% (v/v) bead inoculum and a bead ratio of 55:30:15 for KB, KBP, and MD, respectively. The process demonstrated a high productivity and microbial stability during the 7-week continuous culture. Compared with previous experiments carried out with an inoculum bead ratio of 33:33:33 for KB, KBP, and MD beads, respectively, the modification of the inoculum bead ratio had apparently little effect on free and immobilized, total and specific populations. A dominant behavior of L. diacetylactis MD over the other strains of the mixed culture was observed both with free-cell populations in the effluent and with immobilized-cell populations. Additional experiments were carried out with other strain combinations for continuous inoculation-prefermentation of milk. The data also confirmed the dominance of L. diacetylactis during long-term continuous immobilized-cell fermentations. This dominance may be tentatively explained by the local competition involved in the development of the bead cross-contamination and in citrate utilization by L. diacetylactis strains. The gel beads demonstrated a high rheological stability during the 7-week continuous fermentation even at low KCl supplementation of the broth medium (25 mM KCl).

A distance effect in a manual aiming task to remembered targets: a test of three hypotheses.

It has been noted that manual aiming error and variability when pointing to remembered targets increase as a function of target eccentricity. In the present study we evaluated which one of three hypotheses (target localization, motor, or movement duration) best explains this 'distance effect'. In experiment 1, older and younger participants aimed with their unseen hand at the remembered location of targets distributed between 129 and 309 mm from the starting base. Target presentation time was of either 50 or 500 ms and aiming movements could be initiated following either a 100- or a 10,000-ms recall delay. Participants had either no constraints concerning movement time or were asked to reach the near target in a longer movement time than the farther targets. The results revealed a significant distance effect when no time constraints were imposed but showed a significantly reversed distance effect when the instructions were to reach the near targets in a longer movement time than the far targets. The same results were obtained regardless of target presentation time, recall delay, or age of the participants. These results supported a movement duration interpretation of the distance effect. In experiment 2, a distance effect was replicated when pointing with one's unseen hand toward a remembered target but did not take place when pointing to visible targets. Taken together these results suggest that prolonged movement execution interferes with the stored egocentric target representation.