Showing papers by "Domenico Formica published in 2018"

Smart textile for respiratory monitoring and thoraco‐abdominal motion pattern evaluation

Abstract: The use of wearable systems for monitoring vital parameters has gained wide popularity in several medical fields. The focus of the present study is the experimental assessment of a smart textile based on 12 fiber Bragg grating sensors for breathing monitoring and thoraco-abdominal motion pattern analysis. The feasibility of the smart textile for monitoring several temporal respiratory parameters (ie, breath-by-breath respiratory period, breathing frequency, duration of inspiratory and expiratory phases), volume variations of the whole chest wall and of its compartments is performed on 8 healthy male volunteers. Values gathered by the textile are compared to the data obtained by a motion analysis system, used as the reference instrument. Good agreement between the 2 systems on both respiratory period (bias of 0.01 seconds), breathing frequency (bias of -0.02 breaths/min) and tidal volume (bias of 0.09 L) values is demonstrated. Smart textile shows good performance in the monitoring of thoraco-abdominal pattern and its variation, as well.

Quantitative Analysis of Bradykinesia and Rigidity in Parkinson's Disease.

Abstract: Background: In the last decades, several studies showed that wearable sensors, used for assessing Parkinson’s disease motor symptoms and recording their fluctuations, could provide a quantitative and reliable tool for patient's motor performance monitoring. Objective: The aim of this study is to make a step forward the capability of quantitatively describing PD motor symptoms. The specific aims are: identify the most sensible place where to locate sensors to monitor PD bradykinesia and rigidity, and identify objective indexes able to discriminate PD OFF/ON motor status, and PD patients from healthy subjects. Methods: Fourteen Parkinson's disease patients, (HY total time; total power; smoothness. The last three well described PD OFF/ON motor status, during finger tapping task, with an index finger sensor. During prono-supination task, wrist sensor was able to differentiate PD OFF/ON motor condition. Smoothness index, used as a rigidity descriptor, provided a good discrimination of the PD OFF/ON motor status. Total power index, showed the best accuracy for PD vs healthy discrimination, with any sensor location among index finger, thumb, metacarpus and wrist. Conclusion: The present study shows that, in order to better describe the kinematic features of Parkinsonian movements, wearable sensors should be placed on a distal location on upper limb, on index finger or wrist. The proposed indexes demonstrated a good correlation with clinical scores, thus providing a quantitative tool for research purposes in future studies in this field.

Feature Extraction in Sit-to-Stand Task Using M-IMU Sensors and Evaluatiton in Parkinson's Disease

Abstract: This work proposes a broad analysis for the de-tection of the most relevant features for the sit-to-stand task analysis, in Parkinson's disease (PD) patients and healthysubjects (H). A group of sixteen PD patients and thirteen H subjects have been analyzed, using one magneto-inertial sensor, while the physician administers the UPDRS clinical scale. The PD group has been examined before and after thepharmacological therapy (respectively, OFF and ON phase), in order to monitor the different states of the PD, which implies changes in motor control. By calculating the features of this task, it has been possible to choose the most reliable indexes, already used in this task in order to identify differences in the score assigned through sensors. In addition to that, it has also been possible to find differences in the features' values which the clinical scale and the physician cannotidentify. Our study highlights how wearable motion sensors can detect statistically significant differences between OFF/ON phase and H subjects that the clinical evaluation can not. We conclude that our method provides a deep analysis of the sit-to-stand task with only one M-IMU, allowing to check PD patient status,providing a method for home care monitoring.

Intermittent Theta Burst Stimulation Over Ventral Premotor Cortex or Inferior Parietal Lobule Does Not Enhance the Rubber Hand Illusion.

Abstract: An enhanced sense of prosthesis ownership may be the key for higher amputees’ quality of life. In this study in 28 healthy subjects, neuronavigated intermittent Theta Burst Stimulation (iTBS) delivered over the right ventral premotor cortex or inferior parietal lobule has been tested, compared to sham stimulation, to enhance embodiment in the rubber hand illusion paradigm. Neuromodulation of both areas did not result in an enhancement of embodiment, as assessed by the results collected from a self-evaluation questionnaire for the extent of self-attribution of the rubber hand and proprioceptive drift. In all cases, the difference between synchronous and asynchronous stroking confirms the successful induction of the illusion. It may be speculated that the low consistency of iTBS over brain regions other than primary motor cortex may account for the absence of effect, suggesting to test other neuromodulating techniques, acting on cortical networks different from the ones sensitive to iTBS to enhance artificial hand embodiment.

Smart textile based on FBG sensors for breath-by-breath respiratory monitoring: tests on women

Abstract: The use of wearable systems for monitoring vital parameters has gained wide popularity in several medical fields, especially in the respiratory monitoring. The focus of the present study is the experimental assessment of a male-fit smart textile based on twelve fiber Bragg grating sensors for the monitoring of respiratory parameters on eight female volunteers. In particular, breath-by-breath temporal respiratory parameters (i.e., respiratory period, breathing frequency, duration of inspiratory and expiratory phases), and breath-by-breath volume variations (i.e., tidal volume measurements) have been estimated by the sensor’s outputs of the t-shirt. Results show good agreement between measurements carried out by the smart textile and the reference instrument (i.e., motion capture system with passive markers), with a bias of 0.002 s for the respiratory period and of 0.014 breaths·$\mathbf{min}^{\mathbf {-1}}$ for breathing frequency. However, bias found in the comparison of breath-bybreath tidal volumes discourages the use of the present smart textile for volume monitoring in female population. The promising results promote further development of the system to allow continuous monitoring in clinical setting and for tele-monitoring purposes.

A novel sensor design for accurate measurement of facial somatosensation in pre-term infants

Abstract: Facial somatosensory feedback is critical for breastfeeding in the first days of life. However, its development has never been investigated in humans. Here we develop a new interface to measure facial somatosensation in newborn infants. The novel system allows to measure neuronal responses to touching the face of the subject by synchronously recording scalp electroencephalography (EEG) and the force applied by the experimenter. This is based on a dedicated force transducer that can be worn on the finger underneath a clinical nitrile glove and linked to a commercial EEG acquisition system. The calibrated device measures the pressure applied by the investigator when tapping the skin concurrently with the resulting brain response. With this system, we were able to demonstrate that taps of 192 mN (mean) reliably elicited facial somatosensory responses in 7 pre-term infants. These responses had a time course similar to those following limbs stimulation, but more lateral topographical distribution consistent with body representations in primary somatosensory areas. The method introduced can therefore be used to reliably measure facial somatosensory responses in vulnerable infants.

Design of a Wearable Mechatronic Device to Measure the Wrist Rigidity in Parkinson's Disease Patients

Abstract: The aim of this work is to present a novel wearable mechatronic device (called PDMeter) designed to objectively assess the wrist rigidity in Parkinson's Disease (PD) patients. The system is low-weight, long-term wearable and portable in order to i) perform clinical assessments during Activities of Daily Living (ADLs) in unstructured environments, and ii) to provide several rigidity measurements per day. In this scenario, we defined two different working modalities: i) measurement mode, in which the system measures the wrist rigidity, and ii) backdrivable mode, in which it does not measure, but it has to be transparent for the user during ADLs. In this paper we present the overall mechatronic design of the PDMeter, including the kinematic structure, the actuation system, the sensory system (both force and position) and the control electronics. The overall structure is optimized in terms of dimension and weight: the design of the electronic system allow to integrate in a single compact PCB both the control system and the wireless communication with an external device (laptop or smartphone); the mechanical structure, characterized by one active degree of freedom and five passive ones, is entirely made of aluminium alloy (A16082), and the whole system with the electronics embedded has an overall mass of about 0.46 kg. Future efforts will focus on the implementation and testing of the most suitable algorithms to assess the wrist rigidity, and their validation in clinical trials.

Experimental analysis of the influencing factors on the response of a tool for epidural space detection

Abstract: Epidural injection is a local-regional anesthesia technique used both for analgesic and anesthetic purposes. During the procedure, a needle is inserted between two spinous processes, and it is advanced through interspinous ligament, supraspinous ligament skin, ligamentum flavum, and finally it reaches the epidural space. It is crucial the optimal positioning of the needle's tip within this space to avoid incorrect medication administration or dural puncture. Nowadays, the anaesthetist detects the epidural space by a sense of a resistance loss due to the different density of the mentioned anatomical tissues. In a previous work, we described a bespoke system called Epidural Sensing Management Tool (ESMT) designed to support the anaesthetist in the detection of the epidural space. The system is based on a piezoresistive sensor which measures the pressure exerted by the clinician on the syringe plunger during the procedure. The resistance of the sensor is converted in voltage by a Wheatstone bridge, then is recorded and visualized on a laptop. The aim of this study is twofold: i) to assess the influence of the sensor's active area on the ESMT response; ii) to assess the influence of the resistance value of the Wheatstone bridge on the ESMT response. At this scope, two sensors with different circular area and Wheatstone bridge with three different resistance values were used. The influence of the two mentioned parameters on the ESMT response was investigated by applying known force in a wide range of values. These experiments were performed considering two different configurations: i) the first set of tests was carried out with a 3 mm-thick cylinder of silicon material (taken from an upper limb of cosmetic prosthetic gloves) interposed between the indenter and the sensor; ii) The second set of tests was carried out by placing the thumb of a volunteer between the indenter and the sensor. Also, the sensor is placed on a syringe plunger used during epidural puncture. This configuration is very close to the clinical settings (force applied to the whole area of the plunger by the thumb). As expected, both the sensor model and the Wheatstone bridge resistance significantly influence the metrological characteristics of the proposed system.

Evaluation of Hand-Eye and Robot-World Calibration Algorithms for TMS Application

Abstract: In this paper we compare three approaches to solve the hand-eye and robot-world calibration problem, for their application to a Transcranial Magnetic Stimulation (TMS) system. The selected approaches are: i) non-orthogonal approach (QR24); ii) stochastic global optimization (SGO); iii) quaternion-based (QUAT) method. Performance were evaluated in term of translation and rotation errors, and computational time. The experimental setup is composed of a 7 dof Panda robot (by Franka Emika GmbH) and a Polaris Vicra camera (by Northern Digital Inc) combined with the SofTaxic Optic software (by E.M.S. srl). The SGO method resulted to have the best performance, since it provides lowest errors and high stability over different datasets and number of calibration points. The only drawback is its computational time, which is higher than the other two, but this parameter is not relevant for TMS application. Over the different dataset used in our tests, the small workspace (sphere with radius of 0.05m) and a number of calibration points around 150 allow to achieve the best performance with the SGO method, with an average error of $0.83\pm 0.35mm$ for position and $0.22\pm 0.12deg$ for orientation.

Monitoring Sucking Abilities in Newborns: Design and Validation on Adult Of a Wearable System for Non-Invasive Deglutition Detection

Abstract: Nutritive Sucking (NS) is one of the earliest motor activity performed by infants, strictly related to both neurological and motor development of newborns. The main components of NS are sucking, respiration and deglutition. Despite its recognized importance, current clinical practice lacks quantitative tools for the assessment of NS. This work aims to identify a non-invasive objective method to assess deglutition. In details, we propose a new sensor fusion approach to merge both inertial and acoustic data in order to estimate deglutition time. The algorithm uses two classification criteria: one is based on signal intensity thresholding and the other on the evaluation of Waveform Dimension Trajectory (WDT). Our preliminary results on 9 healthy adult volunteers show that the sensor fusion of audio and IMU signals provides a high precision (0.93) and a good recall (0.72). Moreover, the algorithm has a good accuracy (0.84) and high specificity (0.95).

Design and fabrication of a non-invasive, wireless system for monitoring needle insertion during epidural puncture

Abstract: Over the last decades epidural analgesia has gathered research interest and broad clinical acceptance. In this procedure, the detection of the epidural space is pivotal to avoid major complications. Although, some systems for supporting the anaesthetist in the epidural space detection are commercially available, this difficult procedure is often performed without any support. In previous articles, our research group described a new approach for a non-invasive detection of the epidural space; the assessment of the system was also performed both on a spinal column simulator and in ex vivo animal model (small pig). The mentioned system is based on a Force Sensing Resistor (FSR) that monitors the load exerted by the anaesthesiologist on the syringe plunger during the procedure. The resistance of the sensor is transduced into a voltage by means of a Wheatstone bridge (WB), then it is amplified, finally it is collected by a remote laptop. When the needle reaches the epidural space, the load applied by the anaesthesiologist decreases, so the consequent change of the system output may be used for the detection of the entrance within this space. The previous version of the system communicates to the laptop via USB. In this article, we described a new version of the system which communicates to the laptop via wireless. This solution aims at facilitating the use of the system in clinical settings. After the description of the measuring system, its preliminary assessment in patients undergoing epidural puncture will be reported.