Knowledge, attitude and practices of clinical quality and performance assessment among emergency medical services personnel in South Africa: A mixed methods study.

OBJECTIVE: Deficits in healthcare quality are becoming an increasing concern globally. Within the low- to middle-income country (LMIC) setting insufficient quality has become a bigger barrier to reducing mortality than insufficient access, where 60% of deaths from conditions amenable to healthcare, are due to poor quality care. Measuring quality is key towards improving the effectiveness of healthcare in this setting. METHODS: A mixed methods sequential-explanatory study was conducted, to describe what Emergency Medical Service (EMS) practitioners understood about quality systems within the LMICs, using South Africa as an example. Part 1 consisted of a cross-sectional survey (n = 169), the results of which were utilised to develop a semi-structured interview guide for Part 2. Interviews of participants from Part 1 explored the results of the survey (n = 20) and were analysed through content analysis to develop core categories central to the understanding of quality assessment in the LMICs. RESULTS: Despite relatively poor knowledge of organisational-specific quality systems, understanding of the core components and importance of quality systems was demonstrated. The role of these systems in the LMICs was supported by participants, where the importance of context, system transparency, reliability and validity were essential towards achieving ongoing success and utilisation. The role of leadership and communication towards the effective facilitation of such a system was equally identified. CONCLUSION: Within EMS, quality systems are in their infancy. It could be argued that this is somewhat more pronounced in the LMICs, where knowledge of organisational quality systems was found to be poor. Despite this, there was a strong general understanding of the importance of quality systems, and the role they have to play in this setting.

Processing vertical size disparities in distinct depth planes.

A textured surface appears slanted about a vertical axis when the image in one eye is horizontally enlarged relative to the image in the other eye. The surface appears slanted in the opposite direction when the same image is vertically enlarged. Two superimposed textured surfaces with different horizontal size disparities appear as two surfaces that differ in slant. Superimposed textured surfaces with equal and opposite vertical size disparities appear as a single frontal surface. The vertical disparities are averaged. We investigated whether vertical size disparities are averaged across two superimposed textured surfaces in different depth planes or whether they induce distinct slants in the two depth planes. In Experiment 1, two superimposed textured surfaces with different vertical size disparities were presented in two depth planes defined by horizontal disparity. The surfaces induced distinct slants when the horizontal disparity was more than ±5 arcmin. Thus, vertical size disparities are not averaged over surfaces with different horizontal disparities. In Experiment 2 we confirmed that vertical size disparities are processed in surfaces away from the horopter, so the results of Experiment 1 cannot be explained by the processing of vertical size disparities in a fixated surface only. Together, these results show that vertical size disparities are processed separately in distinct depth planes. The results also suggest that vertical size disparities are not used to register slant globally by their effect on the registration of binocular direction of gaze.

Vertical-disparity gradients are processed independently in different depth planes.

We examined the effects of vertical-disparity gradients on apparent depth curvature of textured surfaces. In Experiment 1, vertical disparities induced expected curvatures when the surface had a horizontal disparity of < +/-40.34'. A central row of elements, lacking vertical disparities, ceased to have the same apparent curvature as the surface when the horizontal disparity between row and surface exceeded +/-5'. In Experiment 2, vertical disparities were not pooled between superimposed surfaces separated by horizontal disparities > +/-10'. Thus, vertical-disparity gradients are not pooled over depth for curvature perception. Our results suggest that vertical disparities are used to determine distances to surfaces directly, rather than to estimate vergence.

A neuroeconomics approach to inferring utility functions in sensorimotor control.

Making choices is a fundamental aspect of human life. For over a century experimental economists have characterized the decisions people make based on the concept of a utility function. This function increases with increasing desirability of the outcome, and people are assumed to make decisions so as to maximize utility. When utility depends on several variables, indifference curves arise that represent outcomes with identical utility that are therefore equally desirable. Whereas in economics utility is studied in terms of goods and services, the sensorimotor system may also have utility functions defining the desirability of various outcomes. Here, we investigate the indifference curves when subjects experience forces of varying magnitude and duration. Using a two-alternative forced-choice paradigm, in which subjects chose between different magnitude-duration profiles, we inferred the indifference curves and the utility function. Such a utility function defines, for example, whether subjects prefer to lift a 4-kg weight for 30 s or a 1-kg weight for a minute. The measured utility function depends nonlinearly on the force magnitude and duration and was remarkably conserved across subjects. This suggests that the utility function, a central concept in economics, may be applicable to the study of sensorimotor control.