Photonic sensors based on flexible materials with FBGs for use on biomedical applications

This chapter is intended for presenting biomedical applications of FBGs embedded into flexible carriers for enhancing the sensitivity and to provide interference-free instrumentation.This work was fully supported by the Algoritmi’s Strategic Project UI 319-2011-2012, under the Portuguese Foundation for Science and Technology grant Pest C/EEI/UI0319/2011

Fiber Bragg Gratings as e-Health Enablers: An Overview for Gait Analysis Applications

Nowadays, the fast advances in sensing technologies and ubiquitous wireless networking are reflected in medical practice. It provides new healthcare advantages under the scope of e-Health applications, enhancing life quality of citizens. The increase of life expectancy of current population comes with its challenges and growing health risks, which include locomotive problems. Such impairments and its rehabilitation require a close monitoring and continuous evaluation, which add financial burdens on an already overloaded healthcare system. Analysis of body movements and gait pattern can help in the rehabilitation of such problems. These monitoring systems should be noninvasive and comfortable, in order to not jeopardize the mobility and the day-to-day activities of citizens. The use of fiber Bragg gratings (FBGs) as e-Health enablers has presented itself as a new topic to be investigated, exploiting the FBGs’ advantages over its electronic counterparts. Although gait analysis has been widely assessed, the use of FBGs in biomechanics and rehabilitation is recent, with a wide field of applications. This chapter provides a review of the application of FBGs for gait analysis monitoring, namely its use in topics such as the monitoring of plantar pressure, angle, and torsion and its integration in rehabilitation exoskeletons and for prosthetic control

Review of human joint monitoring devices: conventional vs. Optical fibre based sensors

Health monitoring devices are highly demanded in order to determine patients’ health condition, to monitor the health recovery progress, and to help the physiotherapist during rehabilitation period of a patient. This paper is focused on knee joint assessment devices and technology implementation. Knee joint angle measurement devices includes many devices such as accelerometer, electro-goniometer, torsiometer, acoustic, visual sensory, and optic fibre. There are several limitations to these technologies which require improvements. Many of the existing techniques and technologies are becoming conventional and there is a need to identify and to explore better methods to enhance the limitations of existing devices. The need of technologies with higher accuracy, reliability, and lower cost have always been a crucial factor. In this paper, a study of conventional and latest technologies are reviewed, and suggested to further explore the implementation of optical fibre based technology for the above-mentioned application. Optical fibre device has faster response, better accuracy, lighter in weight, lower cost, and is not effected by external physical variable such as electromagnetic waves as compared to conventional sensors

Optical goniometer device for continuous monitoring of the knee movement in physiotherapy application

Knee joint is the most crucial among the lower limbs joints due to its exposed location and its major role which carries the entire burden of the body practically our entire life. Hence, by being able to measure the knee joint angle accurately during continuous movement, allows the physiotherapist to detect knee joint damage at early stages before it turns into an injury or permanent scar tissue. Due to the limited number of continuous monitoring devices applicable for diagnosis and treatment stage of the knee, most physicians opted for X-ray and magnetic resonance imaging (MRI) technologies to have some insight on the knee issue before suitable treatment can be recommended. Aside from being expensive for general use of MRI, X-ray on the other hand can cause short-term side effects due to radiation exposure. Knee joint angle measurement devices technologies include but are not limited to the implementation of accelerometer, electrogoniometer, torsiometer, acoustic, visual sensory, and optic fibre. There are many limitations to these technologies that require improvements before they can become clinically applicable such as accuracy issues, limited range of motion measurement, and inability to monitor continuous movement measurement of the knee joint, which have been discussed thoroughly in this research. The need for technologies with higher accuracy, reliability, able to measure the full knee range of motion, applicable for continuous motion measurement and lower cost have always been a crucial factor. The use of optical based devices provides significant contribution in this area due to their advantages such as immunity to electromagnetic interference, lightweight and possibly small sensor setup. However, the application of intensity-based optical fibre sensor for human joint motion detection resulted in limited detection angle, where most sensor are not able to detect angle variation of more than 90ᵒ. To improve this limitation, an optical sensor approach with mechanical-assisted components assembly that translates angular movement to linear movement was developed. The light detection on the photodiode array sensor at different pixels is analysed to represent the angle movement of the knee. The sensor is securely attached to a medical standard knee brace tool to ensure firm sensor placement on the knee area. Based on current study, the proposed optical sensor has a range of motion between 0 to 160ᵒ, with 0.08ᵒ resolution, has a 210.5 sampling rate per second, which allows it to present and record a real time graphical output to demonstrate the knee joint activity performance. Moreover, the proposed device was able to give an excellent internal consistency obtained by Cronbach’s Alpha analysis of 0.967, and has 98.044% correlation with the gold standard goniometer

Stretch sensors for measuring knee kinematics in sports

The popularity of wearable technology in sport has increased, due to its ability to provide unobtrusive monitoring of athletes. This technology has been used to objectively measure kinetic and kinematic variables, with the aim of preventing injury, maximising athletic performance and classifying the skill level of athletes, all of which can influence training and coaching practices. Wearable technologies overcome the limitations of motion capture systems which are limited in their capture volume, enabling the collection of data in-field, during training and competition. Inertial sensors are a common form of technology used in these environments however, their high-cost and complex calibration due to multiple sensor integration can make them prohibitive for widespread use. This thesis focuses on the development of a strain sensor that can be used to measure knee range of motion in sports, specifically rowing and cycling, as a potential low-cost, lightweight alternative to inertial sensors which can also be integrated into clothing, making them more discreet. A systematic review highlighted the lack of alternate technologies to inertial sensors such as strain sensors, as well as the limited use of wearable technologies in both rowing and cycling. Strain sensors were fabricated from a carbon nanotube-natural rubber composite using solvent exchange techniques and employed a piezoresistive sensing mechanism. These were then characterised using mechanical testing, to determine their electrical properties under cyclical strain. The strain sensors displayed hysteretic behaviour, but were durable, withstanding over 4500 strain cycles. Statistical analysis indicated that over 60% of the tests conducted had good intra-test variability with regards to the resistance response range in each strain cycle and sensor response deviating by less than 10% at strain rates below 100 mm/min and less than 20% at a strain rate of 350 mm/min. These sensors were integrated into a wearable sensor system and tested on rowing and cycling cohorts consisting of ten athletes each, to assess the translational use of the strain sensor. This preliminary testing indicated that strain sensors were able to track the motion of the knee during the rowing stroke and cycling pedalling motion, when compared to the output of a motion capture system. Perspectives of participants on the wearable system were collected, which indicated their desire for a system that they could use in their sport, and they considered the translation of this system for real-life use with further development to improve comfort of the system and consistency of the sensor response. The strain sensors developed in this project, when integrated into a wearable sensor system, have the potential to provide an unobtrusive method of measuring knee kinematics, helping athletes, coaches and other support staff make technical changes that can reduce injury risk and improve performance.Open Acces

Biomedical Engineering

Biomedical engineering is currently relatively wide scientific area which has been constantly bringing innovations with an objective to support and improve all areas of medicine such as therapy, diagnostics and rehabilitation. It holds a strong position also in natural and biological sciences. In the terms of application, biomedical engineering is present at almost all technical universities where some of them are targeted for the research and development in this area. The presented book brings chosen outputs and results of research and development tasks, often supported by important world or European framework programs or grant agencies. The knowledge and findings from the area of biomaterials, bioelectronics, bioinformatics, biomedical devices and tools or computer support in the processes of diagnostics and therapy are defined in a way that they bring both basic information to a reader and also specific outputs with a possible further use in research and development

FBG in PVC foils for monitoring the knee joint movement during the rehabilitation process

This paper presents a sensing electronic-free wearable solution for monitoring the body kinematics. The measuring of the knee movements, flexion and extension, with the corresponding joint acting as the rotation axis is shown as working principle. The proposed sensing system is based on a single optical Fiber-Bragg Grating (FBG) with a resonance wavelength of 1547.76 nm. The optical fiber with the FBG is placed inside a new polymeric foil composed by three flexible layers which facilitates its placement in the anatomic parts under investigation while maintaining full sensing capabilities. The way the device is placed in the specific body part to be measured enables the clear detection of the movements in respect to the joint. The proposed solution was tested using a prototype that was built to evaluate the device under different condition tests and also to assess the system’s consistency. The designed and fabricated system demonstrates clear advantages in medical fields like physical therapy applications as optical fiber is not affected by electromagnetic interference nor does the system needs complex and expensive electronic systems and mechanical parts. Another advantage is the possibility to measure, record and evaluate specific mechanical parameters of the limbs’ motion. Patients with bone, muscular and joint related health conditions, as well as athletes, are within the most important end-user applications.Fundação para a Ciência e a Tecnologia (FCT