Visual information processing in hemispatial neglect

Hemispatial neglect is a complex neuropsychological disorder characterized by a severe attentional deficit that produces a lack of awareness for information appearing in contralesional hemispace. Despite this lack of phenomenal awareness, recent studies suggest that a great deal of visual information processing does occur and can influence the performance of patients in certain tasks. The current review will present this evidence and suggest a new theoretical framework that may help to direct future research into uncovering the underlying mechanism(s).     

Measurement and mismeasurement of mood: recurrent and emergent issues

The affective explosion in psychology has led to tremendous advances in mood measurement. Mood ratings reflect a hierarchical structure consisting of two broad dimensions-Positive Affect and Negative Affect-and multiple specific states. Brief scales have been developed that reliably assess Positive and Negative Affect across different populations and time frames, in both between- and within-subject data. We examine controversies related to (a) the content of these higher order scales and (b) the independence of Positive and Negative Affect. Regarding the latter, we show that Positive and Negative Affect scales remain largely independent across a wide range of conditions, even after controlling for random and systematic error. Finally, there remains little consensus regarding the lower order structure of affect. This lack of a compelling taxonomy has substantially slowed progress in assessing mood at the specific affect level.     

Of science, meta-science, and clinical practice: the generalization of a generalization to a particular

Although science is the most powerful method for advancing knowledge and scientific and statistical formalisms are generally much sounder than impressionistic judgment, advanced methodological training (as it is presently comprised) is often of little direct use to practicing clinicians. Practitioners should be able to identify grossly deficient knowledge claims and clear scientific winners, but beyond this, the trick usually is to determine which scientific authority or authorities on whom to depend, a decision task that is ultimately to be tackled through the type of meta-scientific studies that Faust and Meehl have proposed. In applying scientific knowledge, the clinician usually must choose between the generalization of a scientific generalization to a particular versus the application of a clinical generalization to a particular. Determining the relative power of scientific generalizations developed outside, versus clinical generalizations developed within the setting of application, can be very difficult, and there are few established guides. A more advanced science of generalization, another meta-scientific problem, would allow sounder predictions about application to new domains and could greatly aid the practitioner.     

The Patient Self-Determination Act and Advance Directives: Snapshots of Activities in a Tertiary Health Care Center

This study describes the results of a retrospective review of patients' charts who had an advanced directive (AD) and who were hospitalized in a tertiary, acute care teaching hospital. The purpose of the review was to understand from clinical, sociological, ethical and legal perspectives the nature and utility of ADs. Findings and implications of the review are discussed in terms of: patient demographics; diagnoses; quality of ADs; influence of ADs on clinical decisions; and legal aspects of ADs.     

The Convention on Human Rights and Biomedicine of the Council of Europe

The Convention on Human Rights and Biomedicine developed by the Council of Europe, now undergoing ratification, is the first international treaty focused on bioethics. This article describes the background of the Convention's development and its general provisions and provides a comparison of its requirements with those of federal regulations governing research with human subjects. Although most provisions are comparable, there are significant differences in scope and applicability, for example, in the areas of compensation for injury, research participation by persons with limited capacity to consent, assisted reproduction, organ transplantation, and research in emergency situations. The Convention represents a milestone in international bioethics and protection of human rights that will probably be referred to with increasing frequency.     

The effects of periodic visual occlusion on ball catching

Four experiments were conducted to examine the effects of periodic visual occlusion on one-handed ball catching. Tennis balls were projected one at a time over distances of 8-12 m, and liquid-crystal visual occlusion spectacles provided intermittent vision by opening and closing the lens shutters at different frequencies. As well as frequency, we manipulated duty cycle, or the proportion of time that the lenses were open. Generally, catching performance deteriorated as frequency was reduced. Although longer visual samples (i.e., increased duty cycle) mediated this effect to some extent, the most potent variable was the time between visual samples; performance deteriorated rapidly when this interval was greater than 80 ms (i.e., 10 Hz with 20-ms lens open times). Presumably this occurred because subjects had difficulty integrating visual information separated by longer temporal intervals.