Poster B2, Tuesday, August 20, 2019, 3:15 – 5:00 pm, Restaurant Hall
Performance on Word Generation in Schizophrenia: A Linguist’s View
Anna Rosenkranz1, Tilo Kircher2, Arne Nagels3;1University of Cologne, 2Philipps University Marburg, 3Johannes Gutenberg University Mainz
Background and Aim: In verbal fluency (or word generation) tasks, a well-established measure for both executive functions and lexical-semantic abilities, participants are asked to generate as many words as possible from a specific semantic category (semantic fluency) or a specific letter (lexical fluency). Deficits on these tasks are commonly observed in patients with schizophrenia with both negative and positive formal thought disorder symptomatology. On a neuropsychological level, a number of studies suggest an involvement of executive functions, attention, short-term memory, cognitive flexibility, inhibition and verbal intelligence, where the particular role of these neuropsychological domains on verbal fluency task performance is still a topic of critical debate. From a linguistic perspective, verbal fluency involves both intact access to representations and efficient word retrieval processes. With regard to patients with schizophrenia, some studies report disproportionately impairment on semantic fluency indicating semantic access deficits, while others report normal patterns of verbal fluency task performance, with better performance in semantic fluency as compared to lexical fluency, indicating general retrieval difficulties. Typically, only the number of correctly generated words is used as a metric to quantify performance, which do not allow a differentiation between the different cognitive components involved. In this research, we implement additional analyses techniques (such as error types, clustering, switching, word frequency and temporal measures) to compare the lexical contribution for semantic and lexcial fluency performance in patients with schizophrenia. Method: We tested semantic (animals) and lexical (letter p) fluency (each for 60 s) as well as executive functions, attention, working memory and verbal intelligence in patients with schizophrenia (n=50) and age-matched healthy controls (n=36). As valid audio records were needed for the additional analysis, we analysed the verbal fluency performance of a subset of 36 patients with schizophrenia with respect to error types, the number of switches from one subcategory to another and the size of the clusters produced within subcategories, word frequency and temporal measures (e.g. the number of correct words was evaluated as a function of four 15-s time intervals). Results and Conclusion: A strong relationship was found between attention deficits and both semantic and lexical fluency in patients with schizophrenia, suggesting that verbal fluency deficits in general are mainly driven by attention dysfunctions. Disproportionately impairment on semantic fluency, which was reported in previous research was not represented in our results. However, patients with schizophrenia generated fewer words in semantic fluency in comparison to healthy controls. Regarding the additional analysis, results showed that patients with schizophrenia produced more errors in comparison to healthy controls. Furthermore, only positive formal thought disorder was related with the number of errors. Interestingly, regarding clustering and switching, word frequency as well as temporal measures, patients with schizophrenia showed no abnormal pattern. We discuss these findings in light of the role of linguistic processes involved in generating and encoding a response in verbal fluency tasks in patients with schizophrenia.
Themes: Control, Selection, and Executive Processes, Disorders: Acquired
Method: Behavioral