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Biomedical subjects

D Keating

Publications and source records attributed to D Keating.

52 records · Page 3Linked to original sources
PubMed1989

The Pocket Speech Aid.

A rapid-access but limited vocabulary communication aid for the non-vocal and speech impaired is useful in some well defined situations. The design and construction of such a device is described. Three distinct situations have been identified where an aid is essential and an initial evaluation has shown the Pocket Speech Aid to be very successful.

Biomedical Engineering↗
PubMed1986

Augmentation of cardiac function in end-stage heart failure by combined use of dobutamine and amrinone.

A patient with end-stage congestive cardiomyopathy had progressive hemodynamic deterioration while awaiting orthotopic heart transplantation. Attempts to support cardiovascular function by high-dose dobutamine infusions were complicated by life-threatening cardiac arrhythmias. The addition of the noncatecholamine inotropic agent, amrinone, improved ventricular performance, enabling reduction of the dose of dobutamine and resolution of the cardiac arrhythmias. Beta receptor stimulation by dobutamine combined with phosphodiesterase inhibition by amrinone may additively or synergistically augment cardiac function despite severe congestive heart failure and also have an adrenergic "sparing effect."

Aminopyridines↗
PubMed1984

Cognitive arithmetic: comparison of operations.

Adults' performance of simple arithmetic calculations (addition, multiplication, and numerical comparison) was examined to test predictions of digital (counting), analog, and network models. Although all of these models have been supported by studies of mental addition, each leads to a different prediction concerning relations between the times required for addition, multiplication, and numerical comparison. Pairs of single-digit integers were presented and reaction times (RTs) for adding, multiplying, and comparing the stimuli were collected. A high correlation between RT for addition and multiplication of the same digits was obtained. This result is consistent with a network model, but presents difficulties for both analog and counting models. A "ties" effect of no increase in RT with increases in problem size for doubles such as 2 + 2 has been found in previous studies of addition using verification procedures, but was not found with the production task employed in the present study. Instead, a different kind of ties effect was found. Reaction time for both addition and multiplication of ties increased more slowly with problem size than did RT for non-tie problems. This ties effect, and the finding that probability of making errors contributes independently of problem size to RT support a distinction between location and accessibility of information in a network.

Adult↗
PubMedDate not supplied

Comparison of repeatability of the multifocal electroretinogram and Humphrey perimeter.

Functional mapping of the retina by multifocal electroretinographic recordings is now possible. We compared the normal range, repeatability and response topography of this new technique with conventional static Humphrey perimetry to assess its suitability in clinical practice. The multifocal technique was performed on 60 age-matched controls. Measures of repeatability and reproducibility were obtained. Results were then compared with those obtained from a customized perimetry test. In both tests the coefficients of repeatability were found to decrease with eccentricity. The inherent measurement variation between techniques was comparable. Overall system variation indicates that the technique could be a useful tool at the clinical level.

Computer Graphics↗
PubMedDate not supplied

The effect of filter bandwidth on the multifocal electroretinogram.

The effect of filter bandwith on the multifocal electroretinogram was assessed by means of theoretical calculation, electronic simulation and real multifocal electroretinogram recordings. Waveform distortion by high-pass filtering on simulated square waves, normal electroretinogram waveforms and negative electroretinogram waveforms was demonstrated. The theory of the effect of differentiation on electroretinogram waveform shape by electronic filtering indicates that little effect would be observed by changing the input filter cut-off for normal electroretinographic waveform shapes. However, negative electroretinogram waveforms are differentiated when the high-pass filter setting is increased. The differentiation effect artificially recreates a positive component that could be mistaken as a b-wave component. To eliminate this effect when recording multifocal electroretinograms, a high-pass filter setting of less than 1 Hz should be used to preserve the true electroretinographic waveform shape.

Computer Simulation↗
PubMedDate not supplied

An instrument to investigate temporal processing mechanisms with the multifocal ERG.

The multifocal ERG technique is a powerful method of studying the function of different areas of the retina. Display systems such as the CRT, which are commonly used for stimulation, are subject to limitations such as those imposed by the raster method of scanning. This work describes a novel stimulating display using LEDs that retains the established hexagonal areas but overcomes some of the limitations of the CRT display systems. The design and construction of the instrument is described together with some preliminary results.

Electroretinography↗
PubMedDate not supplied

MR-guided localization of suspected breast lesions detected exclusively by postcontrast MRI.

OBJECTIVE: We describe and evaluate a preoperative MRI localization procedure for suspected breast lesions. MATERIALS AND METHODS: Fourteen consecutive patients underwent MR localization of suspected breast lesions discovered with contrast-enhanced MRI but not detected by conventional mammography or ultrasound. In each case diagnostic MRI was repeated after the application of special skin markers. A non-magnetic wire was subsequently inserted into the breast and a second MRI performed to document the position of the wire tip relative to the lesion. RESULTS: The procedure was successful in all 14 patients, enabling excision of the lesion and allowing histological diagnoses. CONCLUSION: We found the described procedure to be quite useful.

Adult↗
PubMedDate not supplied

A versatile speech output communication aid.

A portable, battery-powered communication aid with speech output, which can be operated by patients with limited finger control, is described. The device is sufficiently versatile to try out different methods of selection of words or phrases in the search for an acceptable, portable communication aid for the speech impaired.

Communication Devices for People with Disabilities↗
PubMedDate not supplied

Optical coherence tomography in the diagnosis of subclinical serous detachment of the macula secondary to a choroidal nevus.

We present a case in which optical coherence tomography (OCT) aided in the diagnosis of subretinal fluid (SRF) secondary to a choroidal nevus. A patient with a raised lesion above the left optic disc and distorted central vision was referred to our unit because of suspected choroidal melanoma. Fundus fluorescein angiography and slit-lamp investigation did not indicate any areas of SRF; however, OCT showed serous detachment in the macular area. The lesion was treated with laser photocoagulation and, when reviewed at four weeks post-treatment, repeat OCT scans showed that the area of SRF had cleared. In this case OCT was able to detect a subclinical serous detachment in the macula. This may have important implications in the monitoring of patients with small suspicious lesions.

Aged↗
PubMedDate not supplied

The development of a comprehensive stroke programme in the acute hospital.

Stroke is the third leading cause of death and an important cause of hospital admissions and long term disability. The incidence of stroke is estimated at 200 per 100,000 of the population, Dublin has approximately 2,400 new strokes per annum. In 1989 a comprehensive stroke programme was introduced in St Vincent's Hospital. The aim was to provide patients with a coordinated approach to rehabilitation. A study of the programme was conducted in 1993 by detailed chart review. 129 patients with a clinical diagnosis of stroke were referred to the programme during a 12 month period. 27.13% were under age 65 and 72.87% were over 65 years, 18% died and 44.2% were discharged home, independently mobile. The study findings suggest that the comprehensive stroke programme in St Vincent's Hospital represents a feasible model of care in the acute general hospital setting.

Acute Disease↗