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.

OBJETIVO: Prejuízos em memória de trabalho são comuns na esquizofrenia e possíveis causas de múltiplas características do transtorno. Entretanto, poucos estudos reproduziram achados de padrões específicos de déficits em amostras brasileiras de pacientes com esquizofrenia. O objetivo desta pesquisa foi avaliar a memória de trabalho auditiva e visual na esquizofrenia, verificar se estas habilidades operam como dois sistemas separados, e relacionar possíveis déficits de memória de trabalho com habilidades de funções executivas. MÉTODO: Foram incluídos 20 indivíduos com esquizofrenia e 20 indivíduos saudáveis pareados quanto a sexo, idade e escolaridade. As habilidades avaliadas foram memória de trabalho auditiva e visual, atenção seletiva, controle inibitório, flexibilidade cognitiva e planejamento. RESULTADOS: Os pacientes demonstraram prejuízos em todas as medidas dos testes, exceto em tempo de reação de controle inibitório. Pacientes apresentaram significante correlação entre MT auditiva com medidas de atenção seletiva, controle inibitório, flexibilidade e planejamento. Memória de trabalho visual apresentou correlações com planejamento e flexibilidade. CONCLUSÃO: Este estudo sugere que déficits em memória de trabalho e funções executivas estão presentes em pacientes esquizofrênicos na amostra brasileira avaliada. Alterações nas funções executivas podem levar a incapacidade de adequadas operações de memória de trabalho. Esses achados podem contribuir no delineamento de novos procedimentos de intervenção na esquizofrenia em populações brasileiras.

OBJECTIVE: Working memory impairment is common in schizophrenia and is possibly a cause of multiple features of the disorder. However few studies have replicated such findings of impairment patterns in Brazilian samples. The main target of this study was to assess auditory and visual working memory in patients with schizophrenia, to assess if they work as separate systems, and to correlate working memory deficits with executive functions. METHOD: Twenty subjects with schizophrenia and twenty healthy subjects matched by gender, age, and schooling have participated. The abilities assessed were auditory and visual working memory, selective attention, inhibitory control, cognitive flexibility, and planning. RESULTS: Patients showed declines in all measures evaluated, except for a measure reaction time of inhibitory control. Auditory working memory was correlated to selective attention, inhibition, flexibility and planning while Visual working memory to planning and flexibility. CONCLUSION: The present study suggests that working memory and executive functions deficits are present in patients with schizophrenia in the Brazilian sample evaluated. Alterations in executive functions may lead to incapacity of operation of processes of working memory. These findings may contribute to delineate and develop new strategies of schizophrenia treatment in the Brazilian population.