Compounding and lexical recursion in aphasia and in Alzheimer’s disease / Zoltán Bánréti

Compounding and lexical recursion in aphasia and in Alzheimer’s disease / Zoltán Bánréti. In "Perspectives neuropsycholinguistiques sur l'aphasie - NeuroPsychoLinguistic Perspectives on Aphasia", colloque international organisé par l'Unité de Recherche Interdisciplinaire Octogone de l'Université Toulouse II-Le Mirail (France). Toulouse, 21-23 juin 2012.

Weexamined the lexical recursion by tests requiring productive andrecursive construction of compound words.Broca’s and conduction aphasic subjects and subjects with moderateAlzheimer’s disease (AD), as well as healthy control subjects wereinvolved in the tests.  SomeHungarian compounds have a binary branching structure in which theconstituents are also binary constructions consisting of furtherwords in turn. The rightmost constituent is a deverbal noun with-ó/-ő(-er/-or) affix.These constituentsare the heads taking left-hand words in the role of complement. Theconstruction can be repeated recursively, the operationis called lexicalrecursion, thesecompounds are recursively structured (Dressler 2006). The test material consisted of 63 pictures, each accompanied by a statement referring to it. While the subjects were looking at the pictures, they heard statements. Then a question was asked. To response, the subjects had to create compounds of two, three, and four ultimate constituents recursively. We took their performance with respect to two-constituent compounds as results of activating lexical units “ready-made” stored in lexicon. It was their performance in producing three- and four-constituent compounds that we took to be relevant with respect to their recursive abilities. Frequency effects were also considered. The target three- or four-constituent compounds were all headed by a deverbal noun. First the subjects had to supply a two-part compound, then build a three-part compound based on it, and then a four-part compound based on the latter. Broca’sand conduction aphasics followed the strategy of lexicalsearch:they produced simplewords with synonym/hyperonym meaning, instead of three- and andfour-constituent compounds. In this way, lexical recursion wasavoided. Personswith moderate AD preferred the strategy of exitto syntax.Increasing complexity of the target word triggered this strategy, thenumber of responses involving syntactic phrases grew radically. DPsand embedded sentences were produced instead of three- andfour-constituent compounds. AD subjects avoidedlexical recursion by usingthe strategy of exitto syntax. Thenormal control subjects’ performancedid not exhibit these features. Inother tests we found a deficit of syntactic-structural recursion inBroca’s aphasia but therecursive syntax remained unimpaired in moderate AD(Bánréti-Mészáros-Őrley 2011). Languagehas recursion outside syntax, too: this is lexical recursion. Theresults are explained by the fact that it is not a single recursiveoperation applied at various linguistic levels but rather there areseveral recursive operations boundto various grammatical subsystems that can be selectively impaired.