Articles

Clinical Coverage of an Archetype Repository Over SNOMED-CT.

Sheng Yu et al. — Tue, 17 Apr 2012 04:06:56 PDT

Clinical archetypes provide a means for health professionals to design what should be communicated as part of an Electronic Health Record (EHR). An ever-growing number of archetype definitions follow this health information modelling approach, and this international archetype resource will eventually cover a large number of clinical concepts. On the other hand, clinical terminology systems that can be referenced by archetypes also have a wide coverage over many types of health-care information.

No existing work measures the clinical content coverage of archetypes using terminology systems as a metric. Archetype authors require guidance to identify under-covered clinical areas that may need to be the focus of further modelling effort according to this paradigm.

This paper develops a first map of SNOMED-CT concepts covered by archetypes in a repository by creating a so-called terminological Shadow. This is achieved by mapping appropriate SNOMED-CT concepts from all nodes that contain archetype terms, finding the top two category levels of the mapped concepts in the SNOMED-CT hierarchy, and calculating the coverage of each category. A quantitative study of the results compares the coverage of different categories to identify relatively under-covered as well as well-covered areas. The results show that the coverage of the well-known National Health Service (NHS) Connecting for Health (CfH) archetype repository on all categories of SNOMED-CT is not equally balanced. Categories worth investigating emerged at different points on the coverage spectrum, including well-covered categories such as Attributes, Qualifier value, under-covered categories such as Microorganism, Kingdom animalia, and categories that are not covered at all such as Cardiovascular drug (product).

Dual-frequency Circularly-polarized Patch Antenna with Compact Size and Small Frequency Ratio

Xiulong Bao et al. — Mon, 17 Jan 2011 10:27:43 PST

A novel probe-fed single-layer annular-ring patch antenna for dual-frequency circular polarization is evaluated numerically and experimentally verified. The proposed antenna consists of a small circular patch surrounded by two concentric annular-rings, which is loaded by an unequal lateral cross-slot ground plane. The circularly-polarized frequency ratio of the two resonant modes is tunable to a small value, suitable for wireless communications systems. The patch size of the proposed antenna is reduced by about 53% compared to the conventional circular patch at a given frequency. The radiation characteristics of the novel antenna are also presented.

From Passive to Active Electronic Healthcare Records

Jesus Bisbal et al. — Sat, 15 Jan 2011 06:38:32 PST

Objectives: The provision of patient data to clinicians as and when it becomes available is a general objective of information systems in healthcare. It is known that the timely receipt of patient data can have a significant bearing on healthcare outcomes. One of the on-going tasks is to provide this data in the form of an Electronic Healthcare Record according to some agreed standard. The aim in this paper is to provide patient data in electronic form by pushing the information to the end users as soon it becomes available, in advance of any explicit request from the users.

Methods: This paper describes how an existing record system, the Synapses Federated Healthcare Records Server, has been extended to incorporate active functionality to facilitate pushing the information to enduser applications. The user must specify the information of interest to him, so that the system pushes only information useful to the final user. The approach proposed here relies solely on the use of callbacks through the middleware layer being used, a mechanism available in all existing middleware implementations.

Results: The Synapses Federated Healthcare Records Server which has resulted from this research is a more flexible and scaleable system, capable of fulfilling the needs of a wider range of healthcare organisation than when a strictly passive approach is used. Conclusions: It is shown that healthcare organisation can incorporate a healthcare record system with active functionality without any large investment or significant risk to their existing information systems.

A Vocalisation-based Drawing Interface for Disabled Children

Ted Burke — Thu, 04 Feb 2010 07:31:14 PST

In our work with disabled children at Ireland’s National Rehabilitation Hospital, a problem we have experienced in the facilitation of art activities is that traditional art materials and standard computer drawing programs sometimes prove inaccessible. In this paper, an original system, called “PaintMyVoice” is presented which facilitates the creation of two or three-dimensional images using a variety of novel input modalities. In particular, vocalisations can be used to create original images of a variety of objects, including trees, flowers and landscape elements. Additional input to the system can optionally be provided via mouse, keyboard, switch interface or digital camera depending on the abilities of the user. Here, the program’s user interface is described, with an emphasis on accessibility features. The signal processing techniques used to measure various vocal characteristics including intensity, pitch and other spectral characteristics are outlined. The means of translation from vocalisation to visual representation is also explained for each type of object discussed. This technology facilitates artistic expression by all children, but especially those with severe physical and/or intellectual disabilities. Furthermore, in certain cases, it may be used to provide motivation in therapeutic vocal exercises. Finally, the results of initial user trials are presented.

The Human Eye Position Control System in a Rehabilitation Setting

Yvonne Nolan et al. — Thu, 04 Feb 2010 07:31:13 PST

Our work at Ireland’s National Rehabilitation Hospital involves designing communication systems for people suffering from profound physical disabilities. One such system uses the electro-oculogram, which is an (x,y) system of voltages picked up by pairs of electrodes placed, respectively, above and below and on either side of the eyes. The eyeball has a dc polarisation between cornea and back, arising from the photoreceptor rods and cones in the retina. As the eye rotates, the varying voltages projected onto the electrodes drive a cursor over a mimic keyboard on a computer screen. Symbols are selected with a switching action derived, for example, from a blink. Experience in using this mode of communication has given us limited facilities to study the eye position control system. We present here a resulting new feedback model for rotation in either the vertical or the horizontal plane, which involves the eyeball controlled by an agonist-antagonist muscle pair, modelled by a single equivalent bidirectional muscle with torque falling off linearly with angular velocity. We have incorporated muscle spindles and have tuned them by pole assignment associated with an optimum stability criterion. The dynamics also indicate an integral controller taking its input from a bang-bang element with dead zone. There is, in addition, a pure time delay element involved. Describing Function analysis and simulation demonstrate that in this application the time delay is outside the feedback loop, and is probably associated with set-point generation at a higher level in the brain’s hierarchy of control systems. A second input could be involved at the spindle level, active when tracking predictable target motions.

A New Eccentric Geomagnetic Dipole to give the Correct Dip Pole Locations

Annraoi De Paor et al. — Thu, 04 Feb 2010 07:31:12 PST

In this paper, we describe a new eccentric dipole model of the Earth’s magnetic field. The constraints under which the conventional eccentric dipole model is defined result in predicted dip pole locations that differ significantly from the measured locations. Here, we give a preliminary exposition of a new dipole model which, because it is constrained by the observed dip pole locations, overcomes this problem.

A System for Monitoring Pressures and Spinal Curvature in Spinally Injured People Immobilised on a Spinal Raft

Ruairi De Frein et al. — Thu, 04 Feb 2010 05:15:03 PST

We present a system designed to study the pressure at various ‘hot spots’ on the back of the body and the deformation of the spine experienced by a patient when strapped to a spinal board, and the potential alleviation of both by the addition of an inflatable “spinal raft” (or other similar device). In measuring pressure we devised a system of air-filled sacks interfaced with a PC. Each sack, placed under a particular key point on the body, is inflated until its faces just begin to separate and a switch thereby opens. The pressure reading is then captured and displayed by the computer. Seeking a non-invasive method of measuring the curvature of the vertebral column, we discovered that we could use a magnetometer to measure the vertical displacement of magnetically-tagged vertebrae from a fixed horizontal plane. The results of our study will be employed by an independent body to determine the merits or demerit of the spinal raft.