Is semantic verbal fluency impairment explained by executive function deficits in schizophrenia?

Objective: To investigate if verbal fluency impairment in schizophrenia reflects executive function deficits or results from degraded semantic store or inefficient search and retrieval strategies. Method: Two groups were compared: 141 individuals with schizophrenia and 119 healthy age and education-matched controls. Both groups performed semantic and phonetic verbal fluency tasks. Performance was evaluated using three scores, based on 1) number of words generated; 2) number of clustered/related words; and 3) switching score. A fourth performance score based on the number of clusters was also measured. Results: SZ individuals produced fewer words than controls. After controlling for the total number of words produced, a difference was observed between the groups in the number of cluster-related words generated in the semantic task. In both groups, the number of words generated in the semantic task was higher than that generated in the phonemic task, although a significant group vs. fluency type interaction showed that subjects with schizophrenia had disproportionate semantic fluency impairment. Working memory was positively associated with increased production of words within clusters and inversely correlated with switching. Conclusion: Semantic fluency impairment may be attributed to an inability (resulting from reduced cognitive control) to distinguish target signal from competing noise and to maintain cues for production of memory probes

How formal education and literacy impact on the content and structure of semantic categories

We examined the hypothesis that formal education and literacy impact the richness and precision of semantic knowledge but not the organization of semantic categories and basic mechanisms of access to them.In Experiment 1, adults of varying levels of formal education were presented with semantic fluency tests and a superordinate naming task. Experiment 2 examined the impact of reading proficiency on adults of varying degrees of literacy. They were presented with simple semantic, alternating semantic and phonemic fluency tasks, as well as with literacy-related, reasoning and memory tests.Fluency was analyzed in terms of overall performance, sequential order and speed of responses. Despite lower performance, illiterates and adults with null or limited formal education displayed taxonomic clustering and retrieval by semantic subcategory, as did participants with higher formal education levels. Yet, formal education and literacy slightly speed up access to categories, probably providing useful cues for generating category exemplars.SCOPUS: ar.jinfo:eu-repo/semantics/publishe