Semantic and syntactic processes in aphasia: A review of the literature.

Reviews recent investigations of lexical and syntactic aspects of language comprehension in aphasia. It is argued that these studies support theoretical assumptions concerning the functional independence of various components of normal language processing. Studies of the structure of the lexicon in aphasia provide support for componential theories of lexical semantics in that different types of features of meaning can be selectively disrupted under conditions of brain damage. Studies of sentence comprehension support the existence of a syntactic mechanism that is independent of lexically based heuristic strategies for assigning meaning. There is evidence that these independent elements of language are subserved by different portions of the dominant hemisphere of the brain. Focal brain damage can thus cause selective disruption of components, allowing the separation of elements that are highly integrated in the normal adult. It is suggested that studies of aphasic language, therefore, provide a valuable source of constraints on theories of normal language processing. (PsycINFO Database Record (c) 2010 APA, all rights reserved)