G. D. Bell

Towards an EMG-Controlled Prosthetic Hand Using a 3-D Electromagnetic Positioning System

This paper proposes a novel method of using electromyographic (EMG) potentials generated by the forearm muscles during hand and finger movements to control an artificial prosthetic hand worn by an amputee. Surface EMG sensors were used to record the forearm EMG potential signal via a PC sound card, meanwhile, a novel 3D electromagnetic positioning system together with a data-glove mounted with 11 miniature electromagnetic sensors was used to acquire human hand motion in real time. The synchronized measurement of hand posture and EMG signal are stored as prototypes, in the format of a series of data frames, each comprising a set of positional and orientation posture data and a set of EMG data. A graphical hand model was also generated to visualize the real time hand movement. Further, we propose that only the EMG measurement device be attached to the forearm muscle of the prosthetic hand user. Candidate sets of EMG data acquired in real time will be compared with stored prototypes within each data frame using a pattern recognition approach. Subsequently, the most likely posture data set in this frame will be considered as the numerical expression of the current hand shape and used to control a robotic hand so that it carries out the users desire. With a two-channel EMG measurement device, we first apply frequency analysis on the conditioned raw EMG signal. Then, pattern recognition techniques may be applied to identify the most closely aligned spectrum generated from the data recorded by the dual channel EMG measurement device. Alternatively, when a multi-channel (5-6) EMG measurement device is developed, pattern recognition can be applied on the amplitude of EMG signals to identify the most likely EMG signal distributions. This approach offers several advantages over existing methods. Firstly, it will simplify the classification procedure, saving computational time, secondly, it will reduce the requirement for the optimization process, and finally it will increase the number of recognizable hand shapes and subsequently improve the dexterity of the prosthetic hand and the quality of life for amputees. The database of EMG prototypes could be employed to optimize the accuracy of the system within a machine learning paradigm. By making a range of EMG prototype databases available prosthetic hand users could train themselves to use their prosthesis using the visual reference of the real time hand model to provide feedback

3-D motion system ("data-gloves"): application for Parkinson's disease

In this application, three-dimensional electromagnetic sensors have been integrated into a data-glove to accurately model and capture the motion of the human hand. By modeling the movement of the human hand, this system has been shown to accurately measure the tremor evident in subjects with Parkinsons disease (PD). It was found that 11 sensors were sufficient to model the human hand including all the phalanges. A capture rate of 10 measurements/s was achieved. A discrete Fourier analysis has been applied to extract the tremor frequency from the sensor data time series. Further, an analysis of the instantaneous speed of hand motion has been used to extract clinically significant diagnosis. The technique described is seen to provide an objective and quantitative method for the analysis of clinic conditions, such as PD and essential tremor, as a way to assess the effect of therapeutic interventions.

Computer controlled colonoscopy

Endoscopy of lower gastrointestinal tract which includes colonoscopy provides a visualization of the large intestine in a minimally invasive fashion. Even in the hands of an experienced operator colonoscopy, with present instrumentation, is in many cases long and painful procedure. This projects aim is the development of a new computer controlled endoscope which uses air actuation of a multi-link mechanism with sensory feedback provided by a 3D magnetic sensor placed in the biopsy channel of a gastroenterological endoscope. This novel medical device should successfully integrate two technologies-3D imaging system, accurate and non-radiological method of imaging the colonoscope and 3D actuating along the colon. With these two technologies, protocol for the examination of patients becomes more automatic and faster.

Towards the production of radiotherapy treatment shells on 3D printers using data derived from DICOM CT and MRI: preclinical feasibility studies

Background: Immobilisation for patients undergoing brain or head and neck radiotherapy is achieved using perspex or thermoplastic devices that require direct moulding to patient anatomy. The mould room visit can be distressing for patients and the shells do not always fit perfectly. In addition the mould room process can be time consuming. With recent developments in three-dimensional (3D) printing technologies comes the potential to generate a treatment shell directly from a computer model of a patient. Typically, a patient requiring radiotherapy treatment will have had a computed tomography (CT) scan and if a computer model of a shell could be obtained directly from the CT data it would reduce patient distress, reduce visits, obtain a close fitting shell and possibly enable the patient to start their radiotherapy treatment more quickly. Purpose: This paper focuses on the first stage of generating the front part of the shell and investigates the dosimetric properties of the materials to show the feasibility of 3D printer materials for the production of a radiotherapy treatment shell. Materials and methods: Computer algorithms are used to segment the surface of the patient’s head from CT and MRI datasets. After segmentation approaches are used to construct a 3D model suitable for printing on a 3D printer. To ensure that 3D printing is feasible the properties of a set of 3D printing materials are tested. Conclusions: The majority of the possible candidate 3D printing materials tested result in very similar attenuation of a therapeutic radiotherapy beam as the Orfit soft-drape masks currently in use in many UK radiotherapy centres. The costs involved in 3D printing are reducing and the applications to medicine are becoming more widely adopted. In this paper we show that 3D printing of bespoke radiotherapy masks is feasible and warrants further investigation.

Measurement of the stiffness of endoscopes—a plea for commonality

Editor,—In a previous issue ( (2000) Gut 46:801–8. [OpenUrl][1][PubMed][2] ), Brooker and colleagues described their experience with an exciting new variable stiffness colonoscope. They made the point that a stiffer colonoscope shaft reduces recurrent looping but makes passage through an angulated sigmoid more difficult and causes more stretching and hence pain when loops do occur. Conversely, the more flexible thinner paediatric instruments are better for negotiating a fixed or narrow sigmoid colon but then tend to allow recurrent loop formation later in the procedure. Their randomised trial using either a standard Olympus CF200HL (13.3 mm shaft diameter) or a prototype (Olympus XCF-SH230L—12.9 mm shaft diameter) variable stiffness colonoscope looked very promising although in one case a paediatric Olympus PCF230I (11.3 mm shaft diameter) was required to get past a fixed sigmoid … [1]: {openurl}?query=rft.jtitle%253DMedical%2B%2526%2Bbiological%2Bengineering%2B%2526%2Bcomputing%26rft.stitle%253DMed%2BBiol%2BEng%2BComput%26rft.aulast%253DWehrmeyer%26rft.auinit1%253DJ.%2BA.%26rft.volume%253D36%26rft.issue%253D4%26rft.spage%253D475%26rft.epage%253D479%26rft.atitle%253DColonoscope%2Bflexural%2Brigidity%2Bmeasurement.%26rft_id%253Dinfo%253Apmid%252F10198532%26rft.genre%253Darticle%26rft_val_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Ajournal%26ctx_ver%253DZ39.88-2004%26url_ver%253DZ39.88-2004%26url_ctx_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Actx [2]: /lookup/external-ref?access_num=10198532&link_type=MED&atom=%2Fgutjnl%2F49%2F1%2F154.1.atom

Three-dimensional motion system ("data-gloves"): application for Parkinson's disease and essential tremor

The accurate modelling and analysis of medical treatment plays an important role in modern medical science. This paper describes an attempt to apply current sensor and control techniques to quantitatively measure significant motion of the human body. By modelling the movement of the human hand this system can accurately measure the hand posture and all the phalanges, store the measurements as X,Y,Z absolute positions and the computer can (offline) compute the movement of the hand and phalanges. By applying dedicated embedded electronics a portable and networked system can be realized which may be used in the clinical assessment of stroke patients or medical conditions such as Parkinsons disease. It can be used as both a training instrument and a tool for medical diagnosis and research, leading to objective analysis of medical conditions involving accurate posture measurement of the human body.

An electromagnetic imaging system for remote sign language communication

The technique described in this paper is concerned with the provision of a sign language emulator driven by an array of electromagnetic sensors integrated into a pair of data gloves. The objective is to provide a 3D visualization of the signing performed either end of the telephone link. The link requires an ISDN telephone protocol which is now actively marketed in the UK by the telecommunications industry. The objective of the work is to enable the deaf to communicate across telecommunications links. The sensing system is based on an electromagnetic imaging technique devised for key hole surgery and specifically for guidance of colonoscopes during colonoscopy in the screening and treatment of intestinal cancers. It comprises modules for generating magnetic field, sensing the magnetic field and processing the signals from the first two modules. Sensors are mounted in a pair of gloves and determine a position of the fingers and hands to enable the sign language to be read by a computer. Images could be than transferred via ISDN links anywhere in the world. This system operates in real time and with a position accuracy of a few millimeters and orientation accuracy of less than 1 degree of arc.

Telerobotic control using instructions from human hand motion

Abstract The paper describes a novel method to control the position and orientation of robot manipulator moving in response to real time instructions from human hand motion. The system uses 3D electromagnetic technique to acquire accurate multi-phalange hand motion. The motion parameters are transmitted via Ethemet to a remote robot controller that updates the robot set point in real-time. The hand motion is measured using inductive sensors integrated into a data-glove at key anatomical locations. An RTI00 robot manipulator has been used to test the accuracy and repeatability of the telerobotic posture control obtainable by this method. A posture update rate of 10 updates/s was achieved. The experimental results show the positional accuracy achieved is +/-1mm and orientation angles better than +/-1°. This accuracy is a limitation imposed by the robot manipulator used. The measurement accuracy was found to be much higher than +/-1mm. The paper concludes with possible modes to integrate force feedback within the same posture data glove.