PubMed Health⌕ Search

Biomedical subjects

M S Hawley

Publications and source records attributed to M S Hawley.

9 recordsLinked to original sources
PubMed1996

Providing rehabilitation integrated systems using existing rehabilitation technology.

Achieving appropriate integration of control of multiple assistance devices for an individual is currently limited by available integrated systems. An overview of the provision process for Rehabilitation Integrated Systems (RIS) is presented which stresses the need for detailed assessment of the individual's abilities and requirements. A software system is described which integrates existing assistive applications on a PC in an attempt to provide a flexible RIS which can be tailored more precisely to an individual. This has required the use of both DOS and Windows applications and highlighted problems due to limitations of existing RISs, despite user requirements being taken fully into account. While Windows offers the opportunity to remove some compatibility problems, it is concluded that interfacing standards for both software and hardware are necessary to overcome the problems this approach engenders. For individuals who have to use 'intrinsically slow' user interfaces, it is identified that (i) the availability of quantitative comparisons of efficiency of selection methods and (ii) increased choice of selection methods is important.

Biomedical Engineering↗
PubMed1994

Implementation of a PC-based integrated control system for children.

Children with severe physical disabilities often require a range of technological devices to aid them with the fundamental tasks carried out in everyday life. These tasks areas may include mobility, communication, environment control and computer access for education. The most efficient, and often the most cost-effective, way of providing for these requirements is by the provision of a single, integrated system tailored to the individual's needs and abilities. BASIS, the Barnsley And Sheffield Integrated System, is an integrated control system based on a wheelchair-mounted personal computer (PC) and currently implements the following modules: wheelchair control; a spoken communication package; control of home equipment via infra-red; and a facility to run third-party software. The system presents a consistent and uniform environment to the user for selection and activation of these modules and can be controlled by one to four switches (scanning or directed access), a touch screen, a head pointer or a mouse. Safety considerations have played a central part in the design of the system. BASIS can be tailored to the user's requirements by editing a text file in software and by connecting the appropriate hardware modules to the serial and parallel ports. The graphical user interface has been designed for use by children and employs pictorial representation (icons) of available functions on a colour screen. These icons can be chosen from clip-art or drawn on computer drawing package. It is also possible to scan in and utilize drawings or photographs.(ABSTRACT TRUNCATED AT 250 WORDS)

Activities of Daily Living↗
PubMed1992

Wheelchair-mounted integrated control systems for multiply handicapped people.

Integrated control systems allow disabled people access to multiple functions from a single input device (for example a set of switches). Multiply handicapped users are thereby able to switch efficiently between wheelchair control, communication, computer access and control of their environment, without third-party help. Integrated systems have been developed for multiply handicapped children and adults in the Barnsley area. The design philosophy has concentrated upon utilizing, wherever possible, commercially available assistance devices and remotely controlling these via logic-based integrated control systems tailored to the needs and abilities of the individual client. This approach presents few problems as the inputs to commercially available devices are often based on simple switch control. The systems already supplied have proved, after an initial training period, to be easy to operate and have led to a considerable improvement in quality of life for the users. Computer-based, wheelchair-mounted integrated systems are now being developed. A prototype system currently emulates the logic-based controllers described above, employing the screen to display information on the current status of the system. Future development will move toward a more flexible system which will be able to read a variety of input signals and control a large number of outputs. The system will also have the facility to utilize software-based communications, keyboard emulation and environmental control packages as well as business and education software. Such a system could be easily set up, via software, for use by any disabled person.

Biomedical Engineering↗
PubMed1992

Electrical impedance tomography: prospects for non-invasive control of deep hyperthermia treatments.

Electrical Impedance Tomography (EIT) is assessed as a means of monitoring deep hyperthermia treatments in both phantom and in vivo studies. EIT measurements during heating of an inhomogeneous leg phantom show good correlation with internal temperatures measured with invasive probes. Measurements whilst altering the temperature of the stomach contents in volunteers demonstrate the capability of EIT for imaging temperature change at depth in the torso. Significant problems remain to be overcome before EIT can be used in the clinic; however, the technique may be an important additional control factor as a complement to invasive monitoring.

Body Temperature↗
PubMed1991

Lower limb arterial disease: assessment of risk factors in an elderly population.

Doppler ultrasound measurement of ankle/brachial systolic blood pressure ratio was carried out in 295 elderly (mean 77.3, SEM +/- 0.3, range 68-92 years; males = 180) subjects. Of these, 49.8% (n = 147; males = 86) had evidence of lower limb arterial disease (ankle/brachial systolic blood pressure ratio less than 0.96). On multivariate analyses, excluding ischaemic heart disease as an independent variable, systolic blood pressure and current cigarette pack years were positively related to lower limb arterial disease while BMI and serum high density lipoprotein cholesterol were inversely related (multiple correlation coefficient = 0.277; P less than 0.0001). On including ischaemic heart disease as an independent variable, this was positively associated with lower limb arterial disease; the relationships of the other variables were similar except for a weaker (P = 0.055) relationship with serum high density lipoprotein cholesterol (multiple correlation coefficient = 0.296; P less than 0.0001). While the relationships demonstrated were relatively weak, the findings suggest that reversible risk factors are still relevant in the development of lower limb arterial disease in the elderly.

Aged↗
PubMed1991

Microwave imaging of tissue blood content changes.

Active microwave imaging gives information on the dielectric properties of of the body, allowing the collection of data that are distinct from, but complementary to, those available from other imaging methods based on different radiations. Two types of microwave imaging systems have been developed. The first is a planar system that irradiates the object with a plane wave and collects scattered phase and amplitude data at 1024 points on a parallel plane. The data can be reconstructed using a back propagation technique to give an image of the object. The second type of system is a tomographic scanner, consisting of a multiplexed 64-element circular array of waveguides. The waveguides are electronically scanned, alternately as sources and receivers, to give a complete scan of the object with no mechanical movement. A tomographic 'slice' of the object is reconstructed using spectral domain interpolation. Both systems work at 2.45 GHz with an incident power less than 1 mW cm-2 at the object and require a coupling medium (usually water) between the object and the source/receiver. Imaging parameters are appropriate for clinical use: a spatial resolution of 1 cm, measurement time of a few seconds and contrast resolution of around 1%. The effects of changes in perfusion on images of isolated animal organs are presented. Images have also been obtained, with both systems, of the internal dielectric structure of the forearm and of variations in dielectric properties due to changes of tissue blood content effected by application and release of tourniquets to the upper arm. Results show that these changes are well demonstrated by microwave imaging, and possible clinical applications are discussed.

Animals↗
PubMed1990

Medical imaging with a microwave tomographic scanner.

A microwave tomographic scanner for biomedical applications is presented. The scanner consists of a 64 element circular array with a useful diameter of 20 cm. Electronically scanning the transmitting and receiving antennas allows multiview measurements with no mechanical movement. Imaging parameters are appropriate for medical use: a spatial resolution of 7 mm and a contrast resolution of 1% for a measurement time of 3 s. Measurements on tissue-simulating phantoms and volunteers, together with numerical simulations, are presented to assess the system for absolute imaging of tissue distribution and for differential imaging of physiological, pathological, and induced changes in tissues.

Algorithms↗
PubMedDate not supplied

The influence of tissue layering on microwave thermographic measurements.

Non-invasive thermal imaging and temperature measurement by microwave radiometry has been investigated for medical diagnostic applications and monitoring hyperthermia treatment of cancer, in the context of heterogeneous body structure. The temperature measured by a radiometer is a function of the emission and propagation of microwaves in tissue and the receiving characteristics of the radiometric probe. Propagation of microwaves in lossy media was analysed by a spectral diffraction approach. Extension of this technique via a cascade transmission line model provides an efficient algorithm for predicting the field patterns of aperture antennas contacting multi-layered tissue. A coherent radiative transfer analysis was used to relate the field pattern of a radiating antenna to its receiving characteristics when used as a radiometer probe, leading to a method for simulating radiometric data. Measurements and simulations were used to assess the effect of overlying fat layers upon radiometer response to temperature hot spots in muscle-type media. Results suggest that dielectric layering in tissue greatly influences measured temperatures and should be accounted for in the interpretation of radiometric data.

Fats↗