Poststroke Cognition and the Fight Against the Hard Problem

Abstract

See related article, pages 198–203 In this issue of Stroke , Snaphaan and de Leeuw report on their results obtained from a systematic review on poststroke memory dysfunction.1 Of the 798 articles their search strategy identified, only 5 mentioned memory testing at different poststroke intervals, only 3 studies followed patients for at least 1 year, whereas the largest study contained only 196 patients. The results of the review allow at least 2 conclusions. One is drawn by the authors, in that memory dysfunction, a key element in the “diagnosis” of poststroke dementia, does not follow a linear time course after stroke. Leys et al came to a similar conclusion with regard to poststroke dementia, which was defined as any dementia after stroke.2 Short-term studies over-diagnose cognitive poststroke dysfunction. The finding warns us against making simple models of reality when it comes to poststroke cognitive impairment, and makes us aware that we should save our patients the embarrassment of early, false-positive predictions in this respect. The second conclusion the review allows is that our current knowledge of poststroke cognitive impairment and its long-term development is rather poor, as illustrated by the review’s data on memory dysfunction, a key element in the diagnostic criteria for dementia. The poststroke dementia studies reviewed by Leys et al, although larger and with longer follow-up by some, did not provide any detail either except for the criteria that they used for the diagnosis.2 One may question the value of studying any cognitive details when we can already make diagnoses such as vascular dementia to characterize the condition. We, physicians, are keen on making a diagnosis because it will tell us something about disease cause, spectrum of clinical manifestation, progression, and hopefully also about treatment. Exactly for those reasons we should not be …