Jakub Schlenker

Evaluation of relationship between the activity of upper limb and the piloting precision

Flying an aircraft requires a significant degree of coordination of upper and lower limbs. Such movements tend to be rather uncoordinated in the case of inexperienced pilots which results in inaccurate piloting. The aim of this study is to prove or disprove the dependence of the upper limb activity in relation to the aircraft steering during various actions which are required for precise maneuvering. We also deal with the design of a method to determine the degree of correlation between the movement of the hand and the airplane. The study was conducted on 8 subjects with the same level of experience during 11 hours of flight training on the simulator of type TRD40 and aircraft of type DA40. Subjects performed 14 maneuvers in total. Between takeoff and landing a recurring cycle of four maneuvers has been carried out by the subjects. Repeated maneuvers were in the order from the straight-and-level flight, horizontal turn by 360°, ascend turn by 180°, and descent turn by 180°. Recorded data except for basic flight data (magnetic course, banked and altitude) have been variables depicting the activity of the pilots upper limb. The activity was measured using triaxial accelerometer located on the dorsal side of the distal end of the forearm. The correlation coefficient proved relationship between the upper limb movement and aircraft steering both at bank and altitude. It testifies that change of bank and altitude of aircraft is directly connected with upper limb movements. Resultant activity standard deviation relation correlation coefficient is 0.7.

FlexiGuard: Modular biotelemetry system for military applications

The article presents a FlexiGuard modular biotelemetric system for real-time monitoring of special military units. The main focus of the system is on automated monitoring of special forces via parallel monitoring of each member of the special team individually, witch includes collecting sets of physiologic (or environmental) parameters. The systems consists of a set of sensors (for monitoring temperature, heart rate, acceleration, humidity etc.) and modular sensing unit, which records the measured data and sends them to the visualization unit. The measured values (i.e. heart rate, surface temperature of the body and so on) are then visualized in the graphic user interface of the visualization unit. Testing of the functionality of the system took place in both laboratory and real environment. In the case of carrying out the measurements on 34 soldiers at series of 4 probands at the same time, the sensor networks worked without any loss of signal. During the data transfer to the visualization unit, a loss of approx 0.2% of packets occurred. The system thus can offer information to the commander, which may prove essential for the optimalization of operational strategies, taking the state of wellbeing of the team members into account.

Quantification of Trunk Postural Stability Using Convex Polyhedron of the Time-Series Accelerometer Data

Techniques to quantify postural stability usually rely on the evaluation of only two variables, that is, two coordinates of COP. However, by using three variables, that is, three components of acceleration vector, it is possible to describe human movement more precisely. For this purpose, a single three-axis accelerometer was used, making it possible to evaluate 3D movement by use of a novel method, convex polyhedron (CP), together with a traditional method, based on area of the confidence ellipse (ACE). Ten patients (Pts) with cerebellar ataxia and eleven healthy individuals of control group (CG) participated in the study. The results show a significant increase of volume of the CP (CPV) in Pts or CG standing on foam surface with eyes open (EO) and eyes closed (EC) after the EC phase. Significant difference between Pts and CG was found in all cases as well. Correlation coefficient indicates strong correlation between the CPV and ACE in most cases of patient examinations, thus confirming the possibility of quantification of postural instability by the introduced method of CPV.

Myoelectric arm using artificial neural networks to reduce cognitive load of the user

Today’s multiple degree-of-freedom myoelectric prosthesis relies only on direct control by the processed electromyographic signal. However, it is difficult for the wearer to learn unnatural muscle contractions in order to wield more than three DoFs of the arm. This makes it almost impossible to use more complex prostheses with a larger number of actuators. Methods based on sensor–actuator loop and artificial intelligence may reduce cognitive load of the user by removing low level control, and an intelligent control system would make it needless to micromanage every action. For this purpose, sensor system for body segments motion capture was developed, as well as sensor system for prosthetic limb’s environment motion capture. Neural networks were designed to process data from the sensor systems. For the identification of the knee angle, orientation trackers were used. Neural network predictor of arm positions predicts the shoulder angle using the information about movement of the lower limb. In the case of the periodic/cyclic movements of the legs, such as walking, the control unit uses typical movement patterns of the healthy upper limb. Ultrasonic range sensors are used to create 3D map of objects in the environment around the arm. Neural network predictor of object positions predicts collisions. If the potential collisions are identified, the control unit stops arm movement. The new methods were verified by MATLAB and are designed as a part of assistive technology for disabled people and are to be understood as an original contribution to the investigation of new prosthesis control units and international debate on the design of new myoelectric prostheses.

ASSESSMENT OF POSTURAL INSTABILITY IN PATIENTS WITH A NEUROLOGICAL DISORDER USING A TRI-AXIAL ACCELEROMETER

Current techniques for quantifying human postural stability during quiet standing have several limitations. The main problem is that only two movement variables are evaluated, though a better description of complex three-dimensional (3-D) movements can be provided with the use of three variables. A single tri-axial accelerometer placed on the trunk was used to measure 3-D data. We are able to evaluate 3-D movements using a method based on the volume of confidence ellipsoid (VE) of the set of points obtained by plotting three accelerations against each other. Our method was used to identify and evaluate pathological balance control. In this study, measurements were made of patients with progressive cerebellar ataxia, and also control measurements of healthy subjects, and a statistical analysis was performed. The results show that the VEs of the neurological disorder patients are significantly larger than the VEs of the healthy subjects. It can be seen that the quantitative method based on VE is very sensitive for identifying changes in stability, and that it is able to distinguish between neurological disorder patients and healthy subjects.

An evaluation method of complex movement of the arm during walking based on gyroscope data and angle-angle diagram

The article focuses on a technique of gyroscope data processing and quantifying movement patterns of upper limb during walking. Four cheap gyroscopes were used. Using a novel method based on the trajectory length obtained by plotting shoulder and elbow joint angle vs. each other, provides information for a quantification of the complex arm movement as a whole in the sagittal plane. Two parameters for the evaluation of motion, the trajectory length (TL) and traditional range of motion (ROM), were used to analyze a simple rhythmical movement and identified application possibilities of the new parameter. The Pearsons correlation coefficient indicates very strong correlation between the TL and ROM (r>0.8) for both dominant and non-dominant upper limb. Also, the correlation between the body height and TL or ROM was studied. The correlation between the body height and TL or ROM was a negligible (r<;0.2). This shows the versatility of the proposed parameter.

Determining importance of physiological parameters and methods of their evaluation for classification of pilots psychophysiological condition

At present, several studies exist describing the relevance of human factor in air transport with main focus on pilots and flight safety. Within such studies, monitoring of physiological functions is used. There are lot of physiological parameters and methods of their assessment; however, they are mostly based on principles originating from clinical practice. Yet, sensitivity and specificity of these methods with regard to assessment of aviation professionals — pilots is unknown. Therefore, this paper is oriented towards description of the most common methods for physiological parameters assessment. The paper also describes evaluation methods, which are on experimental level in terms of physiological data evaluation, namely recurrent quantification analysis. Within the research carried out, sample group of pilots was subjected to measurement for evaluation of their psychophysiological condition and performance. Selected evaluation methods were applied on the collected data and importance of those parameters and methods, which provided best classification for level of psychophysiological stress, was evaluated by means of statistical analyses. The results indicate that the most important physiological parameter for psychophysiological condition assessment of pilots is heart electrical activity where the possibility to perform signal processing whilst preserving its importance is provided by linear methods in the time and frequency domain, or alternatively by non-linear methods utilizing recurrent quantification analysis.

Symptomatic arrhythmias due to syringomyelia-induced severe autonomic dysfunction

Syringomyelia is characterized by cavity formation in the spinal cord, most often at C2-Th9 level. Clinical manifestation reflects extent and localization of the spinal cord injury. Cases: 20-year old woman was admitted for recurrent rest-related presyncopes with sudden manifestation. Paroxysms of sinus bradycardia with SA and AV blocks were repeatedly documented during symptoms. There was normal echocardiographic finding, (para) infectious etiology was not proved. Character of the ECG findings raised suspicion on neurogenic cause. Autonomic nervous system testing demonstrated abnormalities reflecting predominant sympathetic dysfunction. Suspicion on incipient myelopathy was subsequently confirmed by MRI, which discovered syringomyelia at Th5 level as the only pathology. A 52-year old man with hypotrophic quadruparesis resulting from perinatal brain injury was sent for 2-years lasting symptoms (sudden palpitation, sweating, muscle tightness, shaking) with progressive worsening. Symptoms occurred in association with sudden increase of sinus rhythm rate and blood pressure that were provoked by minimal physical activity. Presence of significant autonomic dysregulation with baroreflex hyperreactivity in orthostatic test and symptomatic postural orthostatic tachycardia with verticalization-associated hypertension were proved. MRI revealed syringomyelia at C7 and Th7 level affecting sympathetic centers at these levels. Sympathetic fibers dysfunction at C-Th spinal level may cause significant autonomic dysfunction with arrhythmic manifestation.

Using mobile technologies with psychiatric patients: Assessing the potential to reduce risk of developing diseases related to inactivity

Mental disorders, such as schizophrenia, are accompanied by increased morbidity and mortality rates, potentially reducing the lifespan of patients by up to 10 years. Premature deaths in schizophrenia sufferers are caused mainly by cardiovascular diseases and complications related to excessive weight gain and type 2 diabetes mellitus. Gaining weight is, furthermore, often a side effect of medicine prescribed for the treatment of schizophrenia. This is why treatment protocols are putting a greater emphasis on healthy lifestyle and exercise for patients, which may support both weight loss and suppress feelings of anxiety. It is, therefore, important for a doctor to monitor the exercise habits of their patients. This article focuses on telemonitoring of physical activity and other biological parameters in patients with mental disorders, such as schizophrenia, using the recent m-Health technology in the form of a Fitbit Flex activity tracker. The Soma web portal has been created to continuously monitor, visualize and analyse the data measured on patients within the scope of research activities.

Wearable Modular Telemetry System for the Integrated Rescue System Operational Use

The article summarizes the development of the FlexiGuard modular telemetry system designed for enhancing safety of the Integrated Rescue System team members in solving crisis situations and for improving training processes. Further framework solutions, which lead to the development of automatic modular telemetry system allowing for real time monitoring of physiological parameters, are provided as well. The system provides for the signalization of critical states such as exhaustion, mental stress, and overheating. It further provides differentiation between the nature and intensity of movement, including actual and overall energy output, monitoring environmental parameters, and analysis of an intervention or training. The system has been tested in laboratories as well as in the terrain under real circumstances, and the eventual end users participated in its optimization process. Following the theory of games, a model of a transmission system was also created which demonstrates higher transmission efficiency when using higher number of nodes.