Progressive language disorder associated with frontal lobe degeneration

Abstract

Abstract We report a patient KC who presented with a profound disorder of propositional language in association with progressive frontal lobe degeneration. The salient clinical feature was her marked difficulty in responding to open-ended questions, contrasting with the relative preservation of performance on more closed, structured language tasks. Experimental investigations of her language skills revealed significant temporal organizational difficulties. She could generate sentences in sentence completion tasks, although there were errors in thematic role assignment and temporal ordering. She had profound difficulty rearranging written words to form a sentence, despite producing the sentence orally. She was unable to conjoin sentences with an appropriate conjunction. The nature of her language disorder is discussed with reference to traditional categories of aphasia. The case is important in drawing attention to the role of the frontal lobes in language functioning and the potential contribution of processes outside the traditional psycholinguistic categories of phonology, morphology, syntax and semantics. Moreover, KC's clinical presentation falls between that of ‘frontal-lobe’ dementia and ‘progressive aphasia‘, reinforcing the link between those clinical disorders.