Cognitive reserve and individual differences in brain tumour patients.

The aim of the paper is to determine the effects of the cognitive reserve on brain tumour patients' cognitive functions and, specifically, if cognitive reserve helps patients cope with the negative effects of brain tumours on their cognitive functions. We retrospectively studied a large sample of around 700 patients, diagnosed with a brain tumour. Each received an MRI brain examination and performed a battery of tests measuring their cognitive abilities before they underwent neurosurgery. To account for the complexity of cognitive reserve, we construct our cognitive reserve proxy by combining three predictors of patients' cognitive performance, namely, patients' education, occupation, and the environment where they live. Our statistical analysis controls for the type, side, site, and size of the lesion, for fluid intelligence quotient, and for age and gender, in order to tease out the effect of cognitive reserve on each of these tests. Clinical neurological variables have the expected effects on cognitive functions. We find a robust positive effect of cognitive reserve on patients' cognitive performance. Moreover, we find that cognitive reserve modulates the effects of the volume of the lesion: the additional negative impact of an increase in the tumour size on patients' performance is less severe for patients with higher cognitive reserve. We also find substantial differences in these effects depending on the cerebral hemisphere where the lesion occurred and on the cognitive function considered. For several of these functions, the positive effect of cognitive reserve is stronger for patients with lesions in the left hemisphere than for patients whose lesions are in the right hemisphere. The development of prevention strategies and personalized rehabilitation interventions will benefit from our contribution to understanding the role of cognitive reserve, in addition to that of neurological variables, as one of the factors determining the patients' individual differences in cognitive performance caused by brain tumours.

Effects of passive smoking on prenatal and infant development: Lessons from the past.

This paper studies the effect of passive smoking on child development. We use data from a time when the adverse effects of smoking on health were not known and when tobacco was not an inferior good. This allows us to disentangle the effect on foetuses and infants of smoking from that of other indicators of social and economic conditions. We exploit a set of unique longitudinal historical datasets defined at a detailed level of geographical disaggregation, namely the 69 Italian provinces. The datasets record precise information on the per capita consumption of tobacco products, the heights of twenty-year old conscripts in the second half of the 19th century Italy, and other relevant controls. We find a strong negative effect of smoking in the period immediately before and after birth on the height at age 20. Results are robust to changes in specification and consistent across the height distribution.