Semantic Clustering of Category Fluency in Schizophrenia Examined with Singular Value Decomposition
| Autor: | Kerry Ledoux, Kyongje Sung, Erin J. Pickett, Godfrey D. Pearlson, David J. Schretlen, Tracy D. Vannorsdall, Barry Gordon |
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| Rok vydání: | 2012 |
| Předmět: |
Adult
Male Schizophrenia (object-oriented programming) Semantics behavioral disciplines and activities Semantic network Fluency Phonetics Cluster Analysis Humans Verbal fluency test Multidimensional scaling Cluster analysis Language Disorders Language Tests Verbal Behavior Latent semantic analysis General Neuroscience Middle Aged Psychiatry and Mental health Clinical Psychology Schizophrenia Female Neurology (clinical) Psychology Cognitive psychology |
| Zdroj: | Journal of the International Neuropsychological Society. 18:565-575 |
| ISSN: | 1469-7661 1355-6177 |
| DOI: | 10.1017/s1355617712000136 |
| Popis: | 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. |
| Databáze: | OpenAIRE |
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