In this study we sought to minimize

In this study we sought to minimize the variables by focusing on asymptomatic subjects and by exploiting a before-after study design. This approach accounts for confounding variables, such as possible subtle cognitive impairments that have been shown to be present in subjects with “asymptomatic” stenosis, when properly tested [29].This study has, however, a number of limitations. The small sample size is probably the major restraint, although the paired nature of the study design has added enough power to the statistical approach. Furthermore, the nature of the study could not allow a blind design, and the “after” assessment could be biased by expectation or learning effect. We tried, however, to account for this potential bias by using parallel form of the tests validated to limit “practice effects” and by performing psychopathological tests that aimed to detect depressive or anxiety symptoms, which could affect the neuropsychological performance.In conclusion, our results reflect a substantial equivalence of the overall performance at the before- and after-CEA or CAS tests. In two domains, however, the postintervention performance which resulted improved. We cannot exclude that the apparent improvement reflects other variables associated, for instance, with learning or release of anxiety. A confidence, however, in the neurovascular fundament of the observed improvement arises from the significant interaction between the phonological verbal fluency performance and side of the carotid intervention, suggesting that a supposedly “lateralized” function benefits mostly from resolution of a homolateral carotid stenosis. Our findings do, therefore, support the hypothesis that recanalization of stenotic carotid improves brain functions by resolving hypothetical “hypoperfusion” states, associated with the narrowing of the vessels.