Selective retrieval and free emission of category exemplars in schizophrenia

Abstract

In a free emission task, normals, chronic schizophrenics with only positive and those with only negative symptoms generated as many exemplars from natural language categories as they could in three minutes. While the overall output level of both schizophrenic groups was lower than that of the normals, neither showed intrusions of unrelated words, and the temporal distribution of the output was marked by a clustering pattern inconsistent with a selective attention deficit hypothesis. The schizophrenics with negative symptoms tended to produce consistently smaller clusters than the normals and the schizophrenics with positive symptoms, implicating a specific retrieval constriction. The relationship of this to the major negative symptom poverty of speech is discussed.

Flexibility and Variability in Lexicon Usage among Yoruba-Speaking Nigerian Outpatients with Schizophrenia

“…This is consistent with other studies that found an association between the MSTTR and FTD [9,10] . Our study, however, went further by showing that the bulk of association was primarily due to negative FTD as positive FTD was not significantly associated with a lower MSTTR.…”

“…This is said to be particularly apparent in patients with thought disorder [9,10] . Some studies, however, have challenged previous work [6,11] by indicating that no differences exist in TTR between patients with schizophrenia and healthy controls.…”

Levels-of-processing effect on word recognition in schizophrenia

“…Evidence of semantic processing deficits in schizophrenia comes primarily from verbal fluency paradigms in which participants generate words belonging to a specific category (e.g., animals). These studies show a consistent performance impairment (Allen and Frith 1983;Goldberg et al 1998) that is among the strongest neuropsychological discriminators of patients from healthy controls (Arango et al 1999). In a recent study (Moelter et al 2001), we found that impaired animal fluency was related to both aberrant automatic semantic-associative network activation and to impaired controlled processes such as search, access, and selection.…”

Schizophrenic patients exhibit hyper-reflexivity in a semantic categorical priming task

“…Verbal language deficits are well established in schizophrenia (Allen & Frith, 1983;Aloia, Gourovitch, Weinberger, & Goldberg, 1996;Barch et al, 1996;Chen, Wilkins, & McKenna, 1994). Much of the unusual verbal processing in schizophrenia is believed to be the result of odd or inefficient semantic networks.…”