Decision Thresholds and Changes in Risk for Preventive Treatment.

This paper investigates the notion of treatment threshold for preventive treatment with potential side effects in the context of changes in risk. Changes in risk are defined by the concept of nth-order stochastic dominance and concern the effectiveness of preventive treatment, side effects, severity of the potential disease, and comorbidity risk. The impact of a riskier environment on the probability of disease threshold above which the preferable decision is to undergo preventive treatment is shown to depend on both mixed risk averse individual preferences and the configuration of increase in risk considered. These results suggest that neglecting differences between risks when evaluating the treatment threshold is likely to lead to substantial errors in most cost-benefit applications for preventive treatment.

Priority setting in health care and higher order degree change in risk.

This paper examines how priority setting in health care expenditures is influenced by the presence of uncertainty about the severity of the illness and the effectiveness of medical treatment. We provide necessary and sufficient conditions on social preferences under which a social planner will allocate more health care resources to populations at higher risk. Changes in risk are defined by the concept of stochastic dominance up to order n. The shape of the social utility function and an equity weighting function are used to model the inequality aversion of the social planner. We show that for higher order risk changes, the usual conditions on preferences such as prudence or relative risk aversion are not necessarily required to prioritise health care when there are different levels of uncertainty associated with otherwise similar patient groups.

Patterns of recovery following focal hemispheric lesions: relationship between lasting deficit and damage to specialized networks.

PURPOSE: Cognitive deficits that are present in the acute stage of a focal hemispheric lesion tend to be greater and more general than residual deficits, which persist into the chronic stage. We have investigated the patterns of recovery and the relationship between deficits and damage to specialized networks taking as model auditory cognitive functions. Evidence from human psychophysical, activation and neuropsychological studies suggests that sound recognition and sound localization are processed in anatomically and functionally distinct cortical networks, the auditory "What" and "Where" processing streams, that are each present in both hemispheres. Focal left or right hemispheric lesions centred on these networks were found to be associated, in the chronic stage, with the corresponding deficits in sound recognition and/or sound localization. METHODS: We report here on recovery patterns in 24 patients who sustained focal hemispheric lesions and were deficient in sound recognition, sound localization and/or sound motion perception at a first evaluation in the acute (n=9), subacute (n=6) or early chronic stages (n=9). RESULTS: All 24 patients had initially a deficit in sound localization and/or sound motion perception. In the acute stage this deficit occurred without damage to the auditory "Where" stream in almost half of the patients, a situation which was never observed in the early chronic stage. Lack of recovery tended to be associated with damage to the specialized stream plus the persistence of deficits beyond the acute stage, and was only loosely related to the size of the lesion and to the extent of damage to a specialized network. CONCLUSIONS: Our results suggest that different mechanisms underlie deficits and recovery at different time points.

Prudence and optimal prevention for health risks.

Empirical evidence suggests the existence of a positive relationship between fear of sickness (FS) - as measured by the level of future utility lost when sickness occurs - and the level of effort to prevent the occurrence of sickness. By looking theoretically at this issue, we develop new results on the determinants of optimal prevention for health risks. In particular, we show that a sufficient condition to pursue more prevention for an individual with a higher FS than another is to have lower prudence in Kimball's (1990) sense, whatever the distribution of risk. These findings reinforce the role of prudence as a main determinant of the optimal level of prevention.