Disproportionate impairment in semantic verbal fluency in schizophrenia: differential deficit in clustering

Bozikas, Vasilis P.; Kosmidis, Mary H.; Karavatos, Athanasios

doi:10.1016/j.schres.2004.05.001

Cited by 76 publications

(73 citation statements)

References 34 publications

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“…6,12,13 Semantic categorizations are used more frequently because they are based on meaning. Bokat & Goldberg 12 suggest that this makes the semantic task easier than the phonetic task because categorizations are rehearsed more often and require less controlled processing.…”

Section: Discussionmentioning

confidence: 99%

“…5 One way of assessing verbal fluency is to measure two cognitive strategies commonly used by examinees, namely clustering (producing words within clusters or categories) and switching (ability to successfully switch between these clusters or categories). [6][7][8] In patients with SZ, only the switching component of phonemic fluency has been found to be impaired 9 ; however, assessment of semantic fluency revealed that both switching and clustering were affected 8 as compared to healthy controls (HC). Nonetheless, when the total word output was considered, patients and HC appeared to employ the same cognitive strategies.…”

Section: Introductionmentioning

confidence: 99%

“…Nonetheless, when the total word output was considered, patients and HC appeared to employ the same cognitive strategies. 6,10 Further examination of the differences in strategy implementation may help elucidate the cognitive processes involved in each fluency task.…”

Section: Introductionmentioning

confidence: 99%

“…Bozikas et al 6 have reported that a differential deficit in clustering, but not in switching, led to disproportionate worsening of semantic fluency in SZ. Authors have interpreted this as evidence of structural semantic knowledge impairment in SZ.…”

Section: Introductionmentioning

confidence: 99%

“…For example, if switching is intact, the fact that a person's clustering ability is impaired 6 does not necessarily imply impairment of the entire semantic network. Hence, we assumed as working hypothesis that the pronounced semantic fluency deficit observed in SZ relative to controls results from the differential effect of increased neuronal noise.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

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

Berberian

Moraes

Gadelha

et al. 2016

Rev. Bras. Psiquiatr.

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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: Individuals with schizophrenia 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.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

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

Berberian

Moraes

Gadelha

et al. 2016

Rev. Bras. Psiquiatr.

View full text Add to dashboard Cite

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Clustering and switching in semantic fluency: predictors of the development of Alzheimer's disease

Fagundo

López

Romero

et al. 2008

Int J Geriat Psychiatry

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Gait control and executive dysfunction in early schizophrenia

et al. 2013

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Dysexecutive functioning, which is described as an enduring core feature of schizophrenia, has been associated with gait disorders. However, few studies have reported gait disorders in schizophrenia patients. The objective of this study was to examine the association between executive dysfunction and gait performance in recent-onset schizophrenia patients using the dual task paradigm. Thirty-two subjects participated to the study: 17 with recent-onset schizophrenia and 15 healthy age-matched controls. Executive functions were evaluated using the Frontal Assessment Battery, Stroop and Trail-Making tests. Mean values and coefficients of variation (CV) of the temporal gait parameters while single tasking (just walking) and while dual tasking (walking and forward counting, walking and backward counting, walking and verbal fluency) were measured using the SMTEC(®)-footswitch system. We focused on the CV of stride time as this measure has been shown to be the most representative parameter of higher gait control. A strong effect of the stride time was found in the group factor for the verbal fluency dual-task when compared to controls (Cohen's d mean = 1.28 and CV = 1.05). The effect was lower in the other dual tasks, and insignificant in the single task of walking. This study shows that patients exhibit higher stride-to-stride variability while dual tasking than controls. It also shows a stronger impact of verbal fluency on gait regularity compared to the other dual tasks revealing a relationship between the executive dysfunction and gait modification. Those results are in line with the idea that schizophrenia implies not only cognitive but also motor functioning and coordination impairment.

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Disproportionate impairment in semantic verbal fluency in schizophrenia: differential deficit in clustering

Cited by 76 publications

References 34 publications

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

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

Clustering and switching in semantic fluency: predictors of the development of Alzheimer's disease

Gait control and executive dysfunction in early schizophrenia

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