Biomedical subjects

R Hockey

Publications and source records attributed to R Hockey.

5 recordsLinked to original sources

PubMed1992

Review of the benefits of treating hypertension.

The main points covered in this review are as follows: 1. Hypertension is a major determinant of cardiovascular disease (CVD). As such it is a major cause of mortality, potential years of life lost, morbidity and long-term disability. 2. The incidence of CVD is directly related to BP. It is likely that this extends over the full range of BP although some writers believe that a J-curve of risk exists for CHD. 3. The relationship between long-term disability from CVD and BP requires further study. 4. Because of regression dilution bias, the gradient in risk of stroke and CHD with BP has been underestimated in the past. Recent research suggests that the risk of stroke increases at least tenfold and CHD sixfold over a range of usual DBP of 30 mmHg (equivalent to approximately 50 mmHg baseline DBP). 5. The population attributable risk (PAR) of CVD related to general elevation of BP in the population from a mean daily excess of sodium intake of 100 mmol/day is at least 30%. In typical industrialised countries the PAR for stroke and CHD from clinical hypertension is 36% and 22%, respectively. These estimates of PAR provide a guide to the maximum benefit that could result from either restriction of sodium intake in the whole population or ideal management of all persons with hypertension. In practice such targets are unlikely to be realised. 6. Recent analyses of clinical trials of treatment of hypertension suggest that the risk of stroke is reduced at all levels of initial BP to the extent predicted from observational studies.(ABSTRACT TRUNCATED AT 250 WORDS)

Antihypertensive Agents↗

PubMed1991

Peripheral visual changes and spatial attention.

Three experiments are reported investigating the attentional effects of peripheral visual changes. In agreement with previous work, experiment 1 demonstrated facilitatory and inhibitory effects of a peripheral visual change on the latency of peripheral target detection. However, after a few minutes practice the facilitatory effect disappeared entirely. The inhibitory effect, though slightly reduced in later blocks, remained significant. Hence, the two effects are dissociable and not inter-dependent as argued by Maylor (1985). In experiments 2 and 3 the perceptual salience of the peripheral cue was manipulated. With a low energy, barely noticeable cue there was no reduction in either facilitation or inhibition as a function of practice. In contrast, the attentional effects of cues higher in energy tended to diminish with practice. Theoretical implications of these data are discussed.

Adult↗

PubMed1989

Trends in risk factors for vascular disease in Australia.

Data from the National Heart Foundation Risk Factor Prevalence Surveys of 1980 and 1983 were analysed to detect national trends in risk factors for vascular disease in Australia. After statistical adjustment for differences in the demographic characteristics of the two populations of survey participants, our results show trends in smoking and blood pressure that are likely to result in a continuing fall in the incidence of vascular disease. There was a fall in the prevalence of current smoking from 32% to 29% but little change in the average daily consumption of cigarettes by current smokers. The prevalence of previously-undetected hypertension fell significantly from 10% to 7%. A small increase occurred in the proportion of all hypertensive patients who were treated and whose blood pressure was controlled, and a decline of 2.0 mmHg (P less than 0.0001) in mean diastolic blood pressures, but no significant change in mean systolic pressures. Mean total plasma cholesterol levels did not change; average levels of plasma triglycerides fell by 0.11 mmol/L (P less than 0.0001); and mean high-density lipoprotein cholesterol levels increased by 0.03 mol/L (P less than 0.0001). All indices of relative body weight increased between 1980 and 1983; mean body mass index rose by 0.23 with associated rises in the prevalence of obesity and of overweight status. The changes in other factors such as use of added salt, the consumption of alcohol, the level of physical activity and adherence to a special diet, all were in the desirable direction, although minor changes in the survey questionnaire might have served to exaggerate the apparent trends.

Adult↗

PubMed1986

Selective attention and performance with a multidimensional visual display.

Selective attention was studied in four experiments in which stimuli varied in both spatial location and visual form. In Experiment 1 the likely location and likely form of targets were both precued. An advantage was found for cued over uncued forms at both cued and uncued locations. In Experiments 2, 3, and 4, different forms tended to occur at different locations. Regardless of whether a location was cued or uncued, form selective effects were found in accordance with form probability for that location. It was not the case that selective attention simply favored certain locations or certain stimulus forms in preference to others. Rather, selective attention was sensitive to precise combinations of form and location. These results could not be reconciled with mental spotlight notions of spatial selectivity.

Adult↗

PubMed1985

Inhibitory component of externally controlled covert orienting in visual space.

Four experiments are reported that investigate an inhibitory effect associated with externally controlled orienting and first identified by Posner and Cohen (1980, 1984). The effect takes the form of an inability to respond quickly to a stimulus appearing in the same location in the visual periphery as a previous one that produced covert orienting. Several characteristics of the effect are revealed that eliminate possible explanations in terms of response inhibition, masking, and sensory habituation. The inhibitory component of orienting occurs whether or not the first stimulus requires a response (Experiment 1), lasts at least a second (Experiments 1, 2, and 3), affects not only the originally stimulated location but also nearby locations (Experiment 2), is determined by environmental coordinates (Experiment 3), and occurs both in the periphery and at the fovea (Experiment 4). It is concluded that inhibition may act together with an early facilitatory component (Posner & Cohen, 1984) in directing the attention and eye movement systems in order to maintain efficient spatial sampling.

Form Perception↗