engleski

Role of psycholinguistic parameters in lexical- semantic processing in early-course psychosis

Background: Language disorder in schizophrenia is explained by a theory that attributes language abnormalities to abnormalities in the structure and function of semantic memory, which in turn lead to the language abnormalities. The aim of this study was to examine the role of psycholinguistics parameters in lexical-semantic processing of early-course psychosis. Methods: The study included twenty patients who were undergoing a treatment and diagnostic differentiation within early-course psychosis. The control group was matched with the patients in age and sex. The subjects performed four experiments: an explicit semantic matching task, lexical- semantic decision task, elicited-association production test and a forced- choice comprehension test. The experiments measured time and accuracy of lexical-semantic processing. The stimuli were presented visually on a computer screen and were consistently balanced, from the psycholinguistic database Psiholeks_HR. In the database, each of the words is also attributed with the measures and values of the five psycholinguistic parameters: subjective word frequency, imageability, abstractness/concreteness, word familiarity and age of acquisition and word associations. Results: In a semantic matching task, the patient group had lower accuracy and longer reaction times compared with healthy subjects, as well as better accuracy for related word- pairs and longer reaction times for unrelated word-pairs. The lexical-semantic relatedness effect supposes different activation in the semantic memory of related versus unrelated word-pairs. Semantically related pairs are considered to result in a larger spread of activation, as the activation of concept nodes is dependent on shared lexical-semantic features of concepts. The increased activation of concepts in the semantic memory of individuals with schizophrenia is found to be faster spreading and lacking in inhibition in relation to healthy control subjects. In a lexical-semantic decision task, the patient group was significantly less accurate on the taxonomy condition than the control group. The higher activation of shared features in animate concepts demanded heightened inhibition, which failed and resulted in the activation of incorrect relations in the semantic memory and lower accuracy in the patient group. Furthermore, when shared features were not activated, there were no differences in accuracy between the two groups. In elicited- association production test the patient group had longer reaction times on both imageability conditions in relation to the control group. While the control group had shorter reaction times on highly imageable words, the patient group’s reaction times did not differ on account of the imageability condition. In the forced-choice comprehension test the patient group had overall longer reaction times independently of the imageability condition. Both groups statistically more often chose associations that were of high and medium frequency, when compared to low frequency words, and the target group had longer reaction times on high- and medium-frequency words than on low-frequency words. Discussion: In clinical practice, the determination of language classifiers for early-course psychosis could potentially enable the creation of reliable diagnostic markers and instruments for identifying the population with an elevated risk of developing psychotic disorders in schizophrenia spectrum, and predicting the course of the disorder.

psycholinguistics ; lexical-semantic ; early-course psychosis

Rad je prikazan u obliku e-postera na Congress of the Schizophrenia International Research Society (SIRS), Virtual Conference, E-Poster Gallery, 2020.