Neuropsychological differentiation of progressive aphasic disorders

The differentiation of subtypes of primary progressive aphasia (PPA) remains challenging. We aimed to identify optimum neuropsychological measures for characterizing PPA, to examine the relationship between behavioural change and subtypes of PPA and to determine whether characteristic profiles of language, working memory, and behavioural changes occur in PPA. Forty-seven patients with PPA and multi-domain Alzheimer's disease (AD) together with 19 age-matched controls underwent a large battery of working memory and language tests. We found that simple tasks of sentence ordering, narrative production, and buccofacial praxis were particularly useful in differentiating non-fluent/agrammatic variant PPA (nfvPPA) from other PPA subtypes, whereas a test of single word comprehension was useful in detecting semantic dementia (SD). No individual tests were discriminating for logopenic variant PPA (lvPPA) relative to nfvPPA. LvPPA and multidomain AD exhibited similar language profiles. A principal components analysis revealed that characteristic PPA profiles extended beyond the realms of language, in particular, the presence of apraxia in nfvPPA, behavioural changes in SD, and working memory deficits in lvPPA. These findings suggest that not all tests are equally discriminatory for PPA and highlight the importance of a test profile in differentiating PPA. These results also support the view that lvPPA is a focal form of AD and emphasize the difficulties classifying lvPPA.     

A Prophetic Seer Potentiating Us in the Present

In his book Radical Evolution Joel Garreau functions as a prophet and a seer. In presenting a narrative of the future that includes an optimistic view of human nature, he warns that because of the GRIN technologies (genetics, robotics, information technology, and nanotechnology) the quickening evolution of “The Curve” is upon us and could well soon culminate in the mind-boggling social change of “The Singularity.” Garreau considers three scenarios of the technological future: the Heaven Scenario, the Hell Scenario, and the Prevail Scenario. The third wins favor because the heavenly envisionment with its evolution of a superintelligent human who could engineer a species with a greatly extended lifespan is too blissful and the hellish prognostication with its destruction of the human species within the next quarter century is too pernicious. Just right is the middle-of-the-road perspective of the Prevail-Transcend depiction of the future. This third view is indeed more appropriate than the first two scenarios, but a more nuanced form of the third perspective—emphasizing similarly the role of human freedom and responsibility in continuing to reshape human nature but drinking less deeply of the transhumanist elixir and more deeply of a pantransentheistic potion—would constitute a more suitable vision of the future.