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N Donaldson

Publications and source records attributed to N Donaldson.

32 records · Page 2Linked to original sources
PubMed2000

An improved configuration for the reduction of EMG in electrode cuff recordings: a theoretical approach.

A theoretical investigation of different electroneurogram recording techniques using electrode cuffs is presented. A new screened tripole arrangement is proposed with a higher inherent signal to interference ratio than the true tripole, which also allows the nulling of the residual electromyogram signal. The reduction in interference is small because the electrode impedance is large compared to the source resistance.

Biomedical Engineering↗
PubMed2000

Experiments with CHRELMS patient-driven stimulator controllers for the restoration of function to paralysed legs.

This paper examines the control of electrical stimulators for restoring the standing function to paraplegics. Patient-driven controllers are based on the knowledge that standing, using support handles, is guided by the neurologically intact natural motor control system, acting through the arms. One category of patient-driven controller is CHRELMS (Control by Handle Reactions of Leg Muscle Stimulation). The first experiments with patient-driven controllers are reported. Experiments in the CHRELMS control of one volunteer are described. Proportional control did not allow the subject to stand up because of the strategy he used, but integral control was successful. With it, he could stand up and sit down slowly, entirely guided by himself, as well as making other manoeuvres. Without changing controller mode, and by leaning forwards and backwards, he could 'posture switch' his support muscles. These are significant achievements and justify a larger study of patient-driven controllers. The subject's control strategies are discussed.

Computer Graphics↗
PubMed2000

Quality of information on hospice referral.

Good quality referral information provides hospice staff with essential information at a time when patients are particularly vulnerable. An Ideal Referral Criteria tool for measuring the quality of general practitioners' information was piloted at one hospice site. Overall inter-rater reliability was 90%, with individual categories ranging from 19% to 34%. Cronbach's alpha was 0.35. Further psychometric testing is recommended.

Family Practice↗
PubMed2000

Hospital referrals to a hospice: timing of referrals, referrers' expectations, and the nature of referral information.

Hospital referrals to Mary Potter Hospice were reviewed prior to the implementation of a new hospital palliative care support service. The hospital palliative care service aims to improve the communication between health professionals in the acute hospital and hospice, and to advise the hospital staff on its management of terminally ill patients. The purpose of this review was to provide baseline information that would assist the hospice with the planning and future evaluation of the new service. Information included the timing of the referrals, the type of referral information provided by hospital doctors, and their expectations of hospice care. One fifth of patients were referred near to death. While medical information was nearly always provided on referral, information on the psychological, spiritual and social dimensions of care was often absent. A third of hospital doctors expressed their expectation of the hospice as "to take over" the patient's care. This suggests the hospital palliative care support service should encourage health professionals to take a more active role in caring for dying patients. The findings are discussed in relation to the goals of the new hospital palliative care support service.

Aged↗
PubMed1999

Feedback control of unsupported standing.

This paper presents the results of continuing work on feedback control of unsupported standing in paraplegia. Our experimental setup considers a situation in which all joints above the ankle are braced, and stabilising torque at the ankle is generated by stimulation of the plantarflexors. A previous study showed that short periods of unsupported standing with paraplegic subjects could be achieved. In order to improve consistency and reliability of unsupported standing we are currently investigating several modifications to the control strategy. The paper reports progress towards this goal.

Adult↗
PubMed1998

Terminal fears and panic.

A terminally-ill patient is being cared for at home by relatives who have no medical or nursing experience but who are doing their best and are well supported by the holistic care of the community teams. As death becomes imminent, the relatives find themselves out of their depth, they panic and dial 999. The patient is rushed to Accident & Emergency (A & E) and is possibly dead on arrival or shortly afterwards. It is the relatives who now need nursing care, to help them through this totally unexpected upheaval. Aspects of this scenario are explored in this paper.

Caregivers↗
PubMed1998

A strategy used by paraplegics to stand up using FES.

Many paraplegics can stand up if their leg extensor muscles are stimulated without feedback to the stimulator-controller. Their neurologically-intact upper bodies control the motion by exerting forces through the arms. To develop stimulator-controllers, we wish to understand the strategy they use. In two subjects, we measured the handle forces and the posture during standing up. Plotted so as to relate the handle forces to the leg joints, the results show that the upper body helps extend the knees and then the hips: a strategy we call quick knee-locking. This may keep the upper body forces within the limits of its strength.

Electric Stimulation Therapy↗
PubMed1998

A perspective on the control of FES-supported standing.

This special section is about the control of electrical stimulators to restore standing functions to paraplegics. It addresses several important topics regarding the interactions of the intact central nervous systems (CNS) with the artificial control system. The topics are as follows: how paraplegics use their arms to help themselves stand up with functional electrical stimulation (FES); the user-driven artificial control of FES-supported standing up; a controller which is promising for the control of sitting down; the application of reinforcement machine learning for the controllers of standing up; arms-free standing with voluntary upper body balancing and artificially controlled ankle stiffness; and cognitive feedback in balancing. This Commentary introduces the papers in this section and relates them to earlier research.

Electric Stimulation Therapy↗
PubMed1997

Telemetry of forces from proximal femoral replacements and relevance to fixation.

Two proximal femoral replacements were instrumented to enable axial forces to be determined at two sites within the prosthesis: in the main shaft and near the tip of the intramedullary stem. The goal was to measure the changes in force distribution over time, as indicated by the ratio of the two forces. Inductive coupling between a coil worn around the leg and a small implanted coil was used, both to supply power to electronic circuits sealed into a welded cavity in the prosthesis and to telemeter data from the prosthesis. Data from both subjects were recorded over the first two years following surgery. For the first subject, there was an increase in mean shaft force excursions (peak force minus resting force) during level walking from 0.53 x BW after 1 week 2.77 x BW after 23 months. The corresponding mean tip force excursions were 0.13 x BW and 1.74 x BW, respectively. The ratio of mean tip force excursions to shaft force excursions steadily increased over the same period from 25 to 63%. Similar increases over time in the tip/shaft ratio were found during treadmill walking, stair climbing and stair descending. Data from the second subject were obtained for the shaft forces only, and were consistent with those from the first subject. The progressive transfer of axial load from the proximal to the distal part of the IM stem recorded telemetrically, together with radiographic observations, suggested that bone remodelling had taken place together with a less stable interface around the proximal part of the stem. This process evidently began soon after implantation.

Bicycling↗
PubMed1994

On the development of the Medical Research Council trial of alpha-interferon in metastatic renal carcinoma. Urological Working Party Renal Carcinoma Subgroup.

This paper describes the steps taken by the British Medical Research Council (MRC) in developing the MRC RE01 trial, a randomized clinical trial for patients with metastatic renal cancer; we discuss the reasons for adopting a triangular sequential design and the impact that this has upon the monitoring of the trial. It had been suggested to the MRC that a trial of biological agents for metastatic renal carcinoma should be initiated. The Cancer Therapy Committee (CTC) of the MRC, through its associated site specific working parties, is responsible for designing and co-ordinating randomized trials of alternative treatments in cancer in solid tumours. Since no MRC working party for renal carcinoma existed at that time, development began by the formation of an ad hoc group set up under the auspices of the CTC. They assessed, by means of a postal questionnaire, U.K. interest in the trials of, and modalities utilized for, treatment of renal cancer. The responses focused attention on the important questions to ask and indicated the level of potential collaboration. These responses and related clinical and statistical issues suggested a protocol to compare medroxy-progesterone acetate (MPA) against alpha-interferon (alpha-IFN). In view of the special problems of comparing an expensive and potentially toxic therapy with an inexpensive and non-toxic standard, a sequential design was used rather than a fixed sample size design. Statistical issues raised and solutions provided are described. The method of establishing the trial data monitoring committee and a brief review of mortality from renal carcinoma in England and Wales are also included. The trial opened to patient recruitment on 1 January 1992. The formal statements regarding statistical issues that appear in the formal trial protocol (RE01) are set out in the Appendix.

Aged↗
PubMedDate not supplied

Hospital nursing benchmarks: the California Nursing Outcomes Coalition project.

The California Nursing Outcomes Coalition (CalNOC) project is an initiative that has become the largest ongoing nursing quality measurement repository in the nation. Launched in 1996 by California nursing leaders concerned with trends in hospital care, CalNOC has created reliable quality benchmark data to define patient safety thresholds in California. This article describes CalNOC's effort, which aligns with the strategy of the National Quality Forum for measuring and reporting healthcare quality. By tracing the evolution of the CalNOC project and its future potential, we hope to encourage other grassroots efforts to build the database repositories needed for healthcare quality measurement in the 21st century.

American Nurses' Association↗