Publications
Performance of a wearable acoustic system for fetal movement discrimination
Jonathan Lai, Richard Woodward, Yuriy Alexandrov, Qurratul ain Munnee, Christoph C. Lees, Ravi Vaidyanathan , Niamh C. Nowlan
PLOS One
DOI: 10.1371/journal.pone.0195728
Publication Year: 2018 , Page(s): 1-14 vol.13
Tags: Wearable Sensors, Inertial Measurement, Fetal Health, Sensor Fusion
Journal Article
Click for Abstract
Hide Abstract

Fetal movements (FM) are a key factor in clinical management of high-risk pregnancies such as fetal growth restriction. While maternal perception of reduced FM can trigger self-referral to obstetric services, maternal sensation is highly subjective. Objective, reliable monitoring of fetal movement patterns outside clinical environs is not currently possible. A wearable and non-transmitting system capable of sensing fetal movements over extended periods of time would be extremely valuable, not only for monitoring individual fetal health, but also for establishing normal levels of movement in the population at large. Wearable monitors based on accelerometers have previously been proposed as a means of tracking FM, but such systems have difficulty separating maternal and fetal activity and have not matured to the level of clinical use. We introduce a new wearable system based on a novel combination of accelerometers and bespoke acoustic sensors as well as an advanced signal processing architecture to identify and discriminate between types of fetal movements. We validate the system with concurrent ultrasound tests on a cohort of 44 pregnant women and demonstrate that the garment is capable of both detecting and discriminating the vigorous, whole-body ‘startle’ movements of a fetus. These results demonstrate the promise of multimodal sensing for the development of a low-cost, non-transmitting wearable monitor for fetal movements.

..............................................................................................................................................................................................................................................
A biomimicking design for mechanical knee joints
Felix Russell, Yipeng Zhu, William Hey, Ravi Vaidyanathan, Peter Ellison
Bioinspration and Biomimetics
DOI: 10.1088/1748-3190/aad39d
Publication Year: 2018 , Page(s): 1-13 vol.13:5
Tags: biomimetics, biomechanics, robotics, ligaments, above knee prostheses, condylar knee, lower limb
Journal Article
Click for Abstract
Hide Abstract

We present a new bioinspired bicondylar knee joint that requires a smaller actuator size when compared to a constant moment arm joint. Unlike existing prosthetic joints, the proposed mechanism replicates the elastic, rolling and sliding elements of the human knee. As a result, the moment arm that the actuators can impart on the joint changes as function of the angle, producing the equivalent of a variable transmission. By employing a similar moment arm—angle profile as the human knee the peak actuator force for stair ascent can be reduced by 12% compared to a constant moment arm joint addressing critical impediments in weight and power for robotics limbs. Additionally, the knee employs mechanical 'ligaments' containing stretch sensors to replicate the neurosensory and compliant elements of the joint. We demonstrate experimentally how the ligament stretch can be used to estimate joint angle, therefore overcoming the difficulty of sensing position in a bicondylar joint.

..............................................................................................................................................................................................................................................
Gait Analysis Using Pervasive Motion Tracking and Mechanomyography Fusion
R Woodward, S Shefelbine, R Vaidyanathan
IEEE Transactions on Mechatronics
DOI: 10.1109/TMECH.2017.2715163
Publication Year: 2017 , Page(s): 2022-2033 vol.22
Tags: Gait Analysis, Wearable Sensors, Mechanomyography, Inertial Measurement Unit, Pervasive Monitoring, Heterogeneous Sensing
Journal Article
Click for Abstract
Hide Abstract

Muscle activity and human motion are useful parameters to map the diagnosis, treatment, and rehabilitation of neurological and movement disorders. In laboratory and clinical environments, electromyography (EMG) and motion capture systems enable the collection of accurate, high resolution data on human movement and corresponding muscle activity. However, controlled surroundings limit both the length of time and the breadth of activities that can be measured. Features of movement, critical to understanding patient progress, can change during the course of a day and daily activities may not correlate to the limited motions examined in a laboratory. We introduce a system to measure motion and muscle activity simultaneously over the course of a day in an uncontrolled environment with minimal preparation time and ease of implementation that enables daily usage. Our system combines a bespoke inertial measurement unit (IMU) and mechanomyography (MMG) sensor, which measures the mechanical signal of muscular activity. The IMU can collect data continuously, and transmit wirelessly, for up to 10 hours. We describe the hardware design and validation and outline the data analysis (including data processing and activity classification algorithms) for the sensing system. Furthermore, we present two pilot studies to demonstrate utility of the system, including activity identification in six able-bodied subjects with an accuracy of 98%, and monitoring motion/muscle changes in a subject with cerebral palsy and of a single leg amputee over extended periods (~5 hours). We believe these results provide a foundation for mapping human muscle activity and corresponding motion changes over time, providing a basis for a range of novel rehabilitation therapies.

..............................................................................................................................................................................................................................................
Telehealth, Wearable Sensors, and the Internet: Will They Improve Stroke Outcomes Through Increased Intensity of Therapy, Motivation, and Adherence to Rehabilitation Programs?
Burridge JH, Lee ACW, Turk R, Stokes M, Whitall J, Vaidyanathan R, Clatworthy P, Hughes AM, Meagher C, Franco E, Yardley L
Journal of Neurologic Physical Therapy
DOI: 10.1097/NPT.0000000000000183
Publication Year: 2017 , Page(s): S32-S38 vol.41
Tags: Rehabilitation, Wearable Sensors, Muscle Myography, Stroke, Telehealth
Journal Article
Click for Abstract
Hide Abstract

BACKGROUND AND PURPOSE:

Stroke, predominantly a condition of older age, is a major cause of acquired disability in the global population and puts an increasing burden on health care resources. Clear evidence for the importance of intensity of therapy in optimizing functional outcomes is found in animal models, supported by neuroimaging and behavioral research, and strengthened by recent meta-analyses from multiple clinical trials. However, providing intensive therapy using conventional treatment paradigms is expensive and sometimes not feasible because of social and environmental factors. This article addresses the need for cost-effective increased intensity of practice and suggests potential benefits of telehealth (TH) as an innovative model of care in physical therapy.

SUMMARY OF KEY POINTS:

We provide an overview of TH and present evidence that a web-supported program, used in conjunction with constraint-induced therapy (CIT), can increase intensity and adherence to a rehabilitation regimen. The design and feasibility testing of this web-based program, "LifeCIT," is presented. We describe how wearable sensors can monitor activity and provide feedback to patients and therapists. The methodology for the development of a wearable device with embedded inertial and mechanomyographic sensors, algorithms to classify functional movement, and a graphical user interface to present meaningful data to patients to support a home exercise program is explained.

RECOMMENDATIONS FOR CLINICAL PRACTICE:

We propose that wearable sensor technologies and TH programs have the potential to provide most-effective, intensive, home-based stroke rehabilitation.

..............................................................................................................................................................................................................................................
A Wearable Automated System to Quantify Parkinsonian Symptoms Enabling Closed Loop Deep Brain Stimulation
P. Angeles, M. Mace, M. Admiraal, E. Burdet, N. Pavese, and R. Vaidyanathan
Towards Autonomous Robotic Systems
DOI: 10.1007/978-3-319-40379-3_2
Publication Year: 2016 , Page(s): 8-19 vol.9716
Tags: Parkinson
Conference Proceedings
Click for Abstract
Hide Abstract

This study presents (1) the design and validation of a wear- able sensor suite for the unobtrusive capture of heterogeneous signals indicative of the primary symptoms of Parkinson’s disease; tremor, bradykinesia and muscle rigidity in upper extremity movement and (2) a model to characterise these signals as they relate to the symptom sever- ity as addressed by the Movement Disorder Society Unified Parkinson’s Disease Rating Scale (MDS-UPDRS).

The sensor suite and detection algorithms managed to distinguish between the non-mimicked and mimicked MDS-UPDRS tests on healthy subjects (p ≤ 0.15), for all the primary symptoms of Parkinson’s disease. Future trials will be conducted on Parkinsonian subjects receiving deep brain stimulation (DBS) therapy. Quantifying symptom severity and cor- relating severity ratings with DBS treatment will be an important step to fully automate DBS therapy.

..............................................................................................................................................................................................................................................
Fetal movements as a predictor of health
J Lai, N Nowlan, R Vaidyanathan, C J Shaw, C C Lees
Acta Obstetricia et Gynecologica Scandinavica (AOGS),
DOI: 10.1111/aogs.12944
Publication Year: 2016 , Page(s): 968-75 vol.95 (9)
Tags: Fetal Movement, Prenatal Health, Wearable Sensors, Ultrasound
Journal Article
Click for Abstract
Hide Abstract


The key determinant to a fetus maintaining its health is through adequate perfusion and oxygen transfer mediated by the functioning placenta. When this equilibrium is distorted, a number of physiological changes, including reduced fetal growth, occur to favor survival. Technologies have been developed to monitor these changes with a view to prolong intrauterine maturity while reducing the risks of stillbirth. Many of these strategies involve complex interpretation, for example Doppler ultrasound for fetal blood flow and computerized analysis of fetal heart rate changes. However, even with these modalities of fetal assessment to determine the optimal timing of delivery, fetal movements remain integral to clinical decision-making. In high-risk cohorts with fetal growth restriction, the manifestation of a reduction in perceived movements may warrant an expedited delivery. Despite this, there has been little evolution in the development of technologies to objectively evaluate fetal movement behavior for clinical application. This review explores the available literature on the value of fetal movement analysis as a method of assessing fetal wellbeing, and demonstrates how interdisciplinary developments in this area may aid in the improvement of clinical outcomes.

..............................................................................................................................................................................................................................................
Movement decoding using neural synchronisation and inter-hemispheric connectivity from deep brain local field potentials
K Mamun, M Mace, M Lutman, J Stein, X Liu, T Aziz, R Vaidyanathan, S Wang
Journal of Neural Engineering
DOI: http://iopscience.iop.org/article/10.1088/1741-2560/12/5/056011/meta
Publication Year: 2015 , Page(s): 1-18 vol.12
Tags: Brain-Robot Interface, Local Field Potential, Grasp Control, Neural Recording
Journal Article
Click for Abstract
Hide Abstract

Correlating electrical activity within the human brain to movement is essential for developing and refining interventions (e.g. deep brain stimulation (DBS)) to treat central nervous system disorders. It also serves as a basis for next generation brain–machine interfaces (BMIs). This study highlights a new decoding strategy for capturing movement and its corresponding laterality from deep brain local field potentials (LFPs). Approach. LFPs were recorded with surgically implanted electrodes from the subthalamic nucleus or globus pallidus interna in twelve patients with Parkinson's disease or dystonia during a visually cued finger-clicking task. We introduce a method to extract frequency dependent neural synchronization and inter-hemispheric connectivity features based upon wavelet packet transform (WPT) and Granger causality approaches. A novel weighted sequential feature selection algorithm has been developed to select optimal feature subsets through a feature contribution measure. This is particularly useful when faced with limited trials of high dimensionality data as it enables estimation of feature importance during the decoding process. Main results. This novel approach was able to accurately and informatively decode movement related behaviours from the recorded LFP activity. An average accuracy of 99.8% was achieved for movement identification, whilst subsequent laterality classification was 81.5%. Feature contribution analysis highlighted stronger contralateral causal driving between the basal ganglia hemispheres compared to ipsilateral driving, with causality measures considerably improving laterality discrimination. Significance. These findings demonstrate optimally selected neural synchronization alongside causality measures related to inter-hemispheric connectivity can provide an effective control signal for augmenting adaptive BMIs. In the case of DBS patients, acquiring such signals requires no additional surgery whilst providing a relatively stable and computationally inexpensive control signal. This has the potential to extend invasive BMI, based on recordings within the motor cortex, by providing additional information from subcortical regions.

..............................................................................................................................................................................................................................................
Multi-modal locomotion: from animal to application
Lock, R. J., Burgess, S. C., Vaidyanathan, R.
Bioinspiration and Biomimetics
DOI: 10.1088/1748-3182/9/1/011001
Publication Year: 2014 , Page(s): 1-18 vol.9
Tags: Animals, Biomimetics/*instrumentation/*methods, Equipment Design, Gait/*physiology, Humans, Locomotion/*physiology, *Models, Biological, Robotics/*instrumentation/*methods
Journal Article
Click for Abstract
Hide Abstract

The majority of robotic vehicles that can be found today are bound to operations within a single media (i.e. land, air or water). This is very rarely the case when considering locomotive capabilities in natural systems. Utility for small robots often reflects the exact same problem domain as small animals, hence providing numerous avenues for biological inspiration. This paper begins to investigate the various modes of locomotion adopted by different genus groups in multiple media as an initial attempt to determine the compromise in ability adopted by the animals when achieving multi-modal locomotion. A review of current biologically inspired multi-modal robots is also presented. The primary aim of this research is to lay the foundation for a generation of vehicles capable of multi-modal locomotion, allowing ambulatory abilities in more than one media, surpassing current capabilities. By identifying and understanding when natural systems use specific locomotion mechanisms, when they opt for disparate mechanisms for each mode of locomotion rather than using a synergized singular mechanism, and how this affects their capability in each medium, similar combinations can be used as inspiration for future multi-modal biologically inspired robotic platforms.

..............................................................................................................................................................................................................................................
Impact of Marine Locomotion Constraints on a Bio-inspired Aerial Aquatic Wing: Experimental Performance Verification
R. Lock, R. Vaidyanathan, S.C. Burgess
ASME Journal of Mechanisms and Robotics
DOI: 10.1115/1.4025471
Publication Year: 2014 , Page(s): 1-8 vol.6
Tags: biomimetics, aerospace components, aerospace robotics, mobile robots, optimisation, underwater vehicles, aerial aquatic robotic vehicle
Journal Article
Click for Abstract
Hide Abstract

This paper describes the design, fabrication, experimental testing and performance optimization of the morphology of a flapping wing for use on a robot capable of aerial and aquatic modes of locomotion. The focus of the optimization studies is that of wing design for aquatic propulsion. Inspiration for the research stems from numerous avian species which use a flapping wing for the dual purpose of locomotion (propulsion) in both air and water. The main aim of this research is to determine optimal kinematic parameters for marine locomotion that maximize nondimensionalized performance measures (e.g., propulsive efficiency), derived from analysis of avian wing morphing mechanisms that balance competing demands of both aerial and aquatic movement. Optimization of the kinematic parameters enables the direct comparison between outstretched (aerial) and retracted (aquatic) wing morphologies and permits trade-off studies in the design space for future robotic vehicles. Static foils representing the wing in both an extended and retracted orientation have been manufactured and subsequently subjected to testing over a range of kinematics. Details of the purpose built 2 degree-of-freedom (dof) flapping mechanism are presented. The gathered results enable validation of previously developed numerical models as well as quantifying achievable performance measures. This research focuses on the mechanical propulsive efficiencies and thrust coefficients as key performance measures whilst simultaneously considering the required mechanical input torques and the associated thrust produced.

..............................................................................................................................................................................................................................................
A Bio-Inspired Condylar Hinge for Robotic Limbs
Etoundi, A. C.Burgess, S. C., Vaidyanathan, R.,
Journal of Mechanisms and Robotics-Transactions of the Asme
DOI: 10.1115/1.4024471
Publication Year: 2013 , Page(s): 1-8 vol.5
Tags: knee-joint, design, mechanism, flexion, ligaments, movement
Journal Article
Click for Abstract
Hide Abstract
This paper presents a novel condylar hinge for robotic limbs which was inspired by the human knee joint. The ligaments in the human knee joint can be modeled as an inverted parallelogram four-bar mechanism. The knee joint also has a condylar cam mechanism between the femur and tibia bones. The bio-inspired joint mimics the four-bar mechanism and the cam mechanism of the human knee joint. The bio-inspired design has the same desirable features of a human knee joint including compactness, high mechanical advantage, high strength, high stiffness and locking in the upright position. These characteristics are important for robotic limbs where there are often tight space and mass limitations. A prototype hinge joint similar in size to the human knee joint has been designed and tested. Experimental tests have shown that the new condylar hinge joint has superior performance to a pin-jointed hinge in terms of mechanical advantage and stiffness. The prototype hinge has a mechanical advantage that is greater than a pin-jointed hinge by up to 35% which leads to a corresponding reduction in the peak force of the actuator of up to 35% for a squatting movement. The paper also presents a five-step design procedure to produce a combined inverted parallelogram mechanism with a cam mechanism.
..............................................................................................................................................................................................................................................
previous