Is Semantic Fluency Differentially Impaired in Schizophrenic Patients with Delusions?

Abstract

The study of cognitive deficits in schizophrenia has recently focused upon semantics: the study of meaning. Delusions are a plausible manifestation of abnormal semantics because by definition they involve changes in personal meaning and belief. A symptom-based approach was used to investigate semantic and phonological fluency in a group of schizophrenic patients subdivided into those with delusions and those with no current delusions. The results demonstrated that deluded patients only were differentially impaired on a test of semantic fluency in comparison to phonological fluency. All subjects showed the same decline in performance over the time course of both tests indicating that retrieval speed in schizophrenia is no different from that of normal controls. Further analysis of word associations in two semantic categories (animals and body parts), revealed that deluded subjects have a more idiosyncratic organisation for animals. The findings of reduced semantic fluency production and poor logical word associations may represent a disorganised storage of semantic information in deluded patients, which in turn affects efficient access.

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

“…The disproportionate impairment in semantic fluency found in SZ may have been caused by insufficient access and retrieval capabilities (due to the difficulty in selecting words for clustering) and by inhibiting distractors (resulting from increased SNR) 36 rather than by reduced semantic function in SZ per se. 11,15,33 The weak correlation between the number of RW and the working memory-associated trend to increase switching is consistent with working memory models and represents a measure of the inability to focus and/or inhibit distracting information. Instead of being a reflection of insufficient semantic store or absence of search and retrieval strategies, these deficits are the consequence of the ways in which the impairment of the executive function manifests itself.…”

“…17 With this in mind, it is possible to speculate that both groups generated more words in the semantic fluency task because of the broader activation range (there is more to choose from), and that SZ patients were proportionally worse at semantic clustering due to their inability to distinguish between signals (more competition). Furthermore, this would explain why SZ performance improves with cuing, 11 task repetition, 15,33 or prior organization strategies. 29 More specifically, these tactics reduce ''executive'' demands, enabling Data presented as mean 6 standard deviation, unless otherwise specified.…”

Can disorganisation of semantic memory account for the abnormalities of thought in schizophrenia?a controlled experimental study

“…Evidence would also suggest that semantic memory dysfunction could account for the characteristic disorders of thinking processes in schizophrenia, namely formal thought disorder (e.g. Goldberg et al 1998;Aloia et al 1996;Spitzer et al 1994), and delusions (Rossell et al 1998(Rossell et al ,1999, as well as schizophrenic-like language disturbances in psychiatrically well subjects (Moritz et al 1999).…”

Impaired retrieval of semantic information in bipolar disorder: A clustering analysis of category-fluency productions.

“…Multidimensional scaling (MDS) is the most frequently used technique for this (e.g., Aloia et al, 1996;Paulsen et al, 1996;Rossell et al, 1999;Sumiyoshi et al, 2005). This approach is based on the observation that, for a given category cue such as "animals," respondents typically begin naming a cluster of semantically related words, such as "wild/Aftican animals," and then switch to a different cluster, such as "domesfic/farm animals" (Sung et al, 2012;Troyer et al, 1997).…”