Semantic clustering of category fluency in schizophrenia examined with singular value decomposition

Kyongje Sung, Barry Gordon, Tracy Vannorsdall, Kerry LeDoux, Erin J. Pickett, Godfrey D. Pearlson, David Schretlen

Research output: Contribution to journalArticle

Abstract

Decreased productivity on verbal fluency tasks by persons with schizophrenia has been attributed to semantic system abnormalities. Semantic structure is often assessed using multidimensional scaling (MDS) to detect normal and aberrant semantic clustering. However, MDS has limitations that may be particularly problematic for such assessments. Here, we introduce a different clustering technique, singular value decomposition (SVD), to elucidate abnormalities of the semantic system in schizophrenia. We compared 102 treated outpatients with schizophrenia to 109 healthy adults on two category-cued word fluency tasks. Patients with schizophrenia showed semantic clustering patterns that differ markedly from those of healthy adults. However, SVD revealed more detailed and critical semantic system abnormalities than previously appreciated using MDS. Patients with schizophrenia showed less coherent semantic clustering of both low- and high-frequency category exemplars than healthy adults. These results suggest the intriguing possibility that impaired automatic activation of semantic information is a key deficit in schizophrenia.

Original languageEnglish (US)
Pages (from-to)565-575
Number of pages11
JournalJournal of the International Neuropsychological Society
Volume18
Issue number3
DOIs
StatePublished - May 2012

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Keywords

  • Latent semantic analysis
  • Lexical retrieval
  • Schizophrenia
  • Semantic network
  • Verbal fluency
  • Word association

ASJC Scopus subject areas

  • Clinical Neurology
  • Psychiatry and Mental health
  • Clinical Psychology
  • Neuroscience(all)
  • Language and Linguistics
  • Linguistics and Language

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