Combining executive function training and anomia therapy in chronic post-stroke aphasia: A preliminary study of multidimensional effects

Executive functions (EFs)-a set of general-purpose control processes that regulate one's thoughts and behaviors-have become a popular research topic lately and have been studied in many subdisciplines of psychological science. This article summarizes the EF research that our group has conducted to understand the nature of individual differences in EFs and their cognitive and biological underpinnings. In the context of a new theoretical framework that we have been developing (the unity/diversity framework), we describe four general conclusions that have emerged from our research. Specifically, we argue that individual differences in EFs, as measured with simple laboratory tasks, (1) show both unity and diversity (different EFs are correlated yet separable); (2) reflect substantial genetic contributions; (3) are related to various clinically and societally important phenomena; and (4) show some developmental stability.

This paper reviews 10 principles of experience-dependent neural plasticity and considerations in applying them to the damaged brain. Neuroscience research using a variety of models of learning, neurological disease, and trauma are reviewed from the perspective of basic neuroscientists but in a manner intended to be useful for the development of more effective clinical rehabilitation interventions. Neural plasticity is believed to be the basis for both learning in the intact brain and relearning in the damaged brain that occurs through physical rehabilitation. Neuroscience research has made significant advances in understanding experience-dependent neural plasticity, and these findings are beginning to be integrated with research on the degenerative and regenerative effects of brain damage. The qualities and constraints of experience-dependent neural plasticity are likely to be of major relevance to rehabilitation efforts in humans with brain damage. However, some research topics need much more attention in order to enhance the translation of this area of neuroscience to clinical research and practice. The growing understanding of the nature of brain plasticity raises optimism that this knowledge can be capitalized upon to improve rehabilitation efforts and to optimize functional outcome.

Milner's (1963) report of impaired performance on the Wisconsin Card Sorting Test (WCST) in a group of patients with frontal lobe lesions suggested that this test might be a useful one in the investigation of individual patients with suspected brain lesions. However, for many of our older hospital population the WCST was found to be too difficult and distressing, and also the inherent ambiguities associated with certain responses limited the test's usefulness for research purposes. Therefore, a simpler and less ambiguous modification was devised (MCS) and a new method of measuring perseverative errors proposed. In a group of 53 patients with unilateral cerebral lesions, those with frontal lobe lesions performed less well with the MCST and made a higher proportion of perseverative errors than those with lesions elsewhere: there were no laterality effects in either frontal or non-frontal groups. The usefulness of the MCST for detecting frontal lobe lesions in individual patients was established, and the use of cut-off scores briefly discussed.