Semantic dementia: demography and neuropsychological assessment in a cohort of 82 cases

Serge Belliard; Catherine Merck; Pierre Yves Jonin; Sandrine Lemoal; Martine Vercelletto



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Semantic dementia: demography and neuropsychological assessment in a cohort of 82 cases
Revue de neuropsychologie. Volume 3, Number 4, 257-65, Décembre 2011, Dossier
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Author(s) : Serge Belliard, Catherine Merck, Pierre Yves Jonin, Sandrine Lemoal, Martine Vercelletto
Summary : Semantic Dementia (SD) is a subject of a rich literature, but few large series are available. We report the demographics and neuropsychological data of a cohort of 82 patients followed prospectively for 20 years. Semantic Dementia begins before age 65 in 75 % of cases, but we have hold this diagnosis in two subjects over 80 years. In accordance with the classification of the French consensus of 2008, initially 71 % of patients could be classified as typical SD with an isolated, multimodal semantic memory impairment. 11 % could be classified as atypical SD due to pure verbal semantic impairment and 18 % as atypical SD because of the existence of discrete extralinguistic disorders (type 2). Two years later, 28.5 % of typical SD exhibited extralinguistic disturbances and all initial pure verbal SD exhibited multimodal semantic memory impairment. Although classified as a subtype of progressive aphasia, SD is more than a semantic verbal deficit in the vast majority of cases.
Keywords : semantic dementia, semantic memory, frontotemporal dementia