How Luria and Vinogradova's theory on the dynamics of the semantic systems could explain an unusual case of lexical comprehension disorders

According to Luria and Vinogradova (1959) the relationships among different words may change in various physiological and pathological conditions. In normal subjects, and in patients with mild or moderate forms of brain damage, a dominant position is assumed by words semantically related to the target. On the contrary, in patients with severe language impairment the dominance of the more complex semantic connections disappear and the simpler sound connections remain preeminent. This theory allowed us to explain the unusual pattern of lexical comprehension errors shown by our patient G.P., affected by a severe form of slowly progressive aphasia. On word-picture matching tasks this patient showed a strong tendency to point more to the phonological distractors than to the semantic distractors, in spite of a massive anomia and of a spared capacity to apprehend the phonological shape of words. This unusual form of lexical comprehension disorder was explained by assuming: (a) that G.P. could covertly evoke a phonological label from pictures that he was unable to name; (b) that, in agreement with Luria and Vinogradova’s theory, this covert activation usually concerned a whole cluster of words having in common a certain number of phonological features. © 1995, Taylor & Francis Group, LLC. All rights reserved.