Executive function in first-episode schizophrenia: A three-year longitudinal study of an ecologically valid test

Department of Psychiatry, The University of Hong Kong, Queen Mary Hospital, 102 Pokfulam Road, Hong Kong.
Schizophrenia Research (Impact Factor: 3.92). 12/2010; 126(1-3):87-92. DOI: 10.1016/j.schres.2010.11.023
Source: PubMed


Executive function impairment is a key cognitive deficit in schizophrenia. However, traditional neuropsychological tests of executive function may not be sensitive enough to capture the everyday dysexecutive problems experienced by patients. Additionally, existing literature has been inconsistent about longitudinal changes of executive functions in schizophrenia. The present study focuses on examining the longitudinal change of executive functions in schizophrenia using the Modified Six Elements Test (MSET) that was developed based on the Supervisory Attentional System model and shown to be sensitive to everyday dysexecutive problems. In the present study, MSET performance was assessed in 31 medication-naïve first-episode schizophrenic patients at four times over a period of three years, while the 31 normal controls were assessed once. Patients demonstrated impairment in MSET as compared to controls. Importantly, the MSET impairment persisted from the medication-naïve state to clinical stabilization and the three years following the first psychotic episode though patients improved in a conventional executive test (Modified Wisconsin Card Sorting Test). Performance was not related to intelligence, educational level, symptom changes, age-of-onset, or duration of untreated psychosis. Better MSET performance at medication-naïve state predicted improvement in negative and positive symptoms over the three-year period. These findings may suggest that MSET impairment is a primary deficit in schizophrenia that occurs early in the course of the illness and remains stable irrespective of clinical state for at least three years following the first episode of schizophrenia.

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Available from: Sherry K W Chan, Feb 27, 2014
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    • "There is no established consensus of which tests are best suited to assess executive functions, nor is there any single test that assesses all components of executive function. Thus, some criticism has been directed towards an inconsistently defined executive domain (Bozikas and Andreou, 2011) and longitudinal studies have shown ambiguous findings (Liu et al., 2011). Executive functioning is a multi-dimensional construct covering several subprocesses including, working memory, fluency, flexibility, inhibitory control and problem-solving. "
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    ABSTRACT: Executive functioning is a multi-dimensional construct covering several sub-processes. The aim of this study was to determine whether executive functions, indexed by a broad range of executive measures remain stable in first episode psychosis (FEP) over time. Eighty-two patients and 107 age and gender matched healthy controls were assessed on five subdomains of executive functioning; working memory, fluency, flexibility, and inhibitory control at baseline and at 1 year follow-up. Results showed that patients performed significantly poorer than controls on all executive measures at both assessment points. In general executive functions remained stable from baseline to follow-up, although both groups improved on measures of inhibitory control and flexibility. In phonemic fluency, controls showed a slight improvement while patients showed a slight decline. Investigation of individual trajectories revealed some fluctuations in both groups over time, but mainly supports the group level findings. The implications of these results are discussed. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.
    06/2015; 228(3). DOI:10.1016/j.psychres.2015.05.060
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    • "A person who cannot integrate information from gaze may get some troubles in abstract thinking [31,32]. Because visual searching seems to be influenced by a “top-down process” [14], patients with schizophrenia who have executive dysfunctions may have ineffective searching strategies when abstract thinking is required [33]. It is unclear what mechanism is underlying this relationship between defects in abstract thinking and abnormalities in oculomotor movement or visual searching behaviors. "
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    ABSTRACT: Effective integration of visual information is necessary to utilize abstract thinking, but patients with schizophrenia have slow eye movement and usually explore limited visual information. This study examines the relationship between abstract thinking ability and the pattern of eye gaze in patients with schizophrenia using a novel theme identification task. Twenty patients with schizophrenia and 22 healthy controls completed the theme identification task, in which subjects selected which word, out of a set of provided words, best described the theme of a picture. Eye gaze while performing the task was recorded by the eye tracker. Patients exhibited a significantly lower correct rate for theme identification and lesser fixation and saccade counts than controls. The correct rate was significantly correlated with the fixation count in patients, but not in controls. Patients with schizophrenia showed impaired abstract thinking and decreased quality of gaze, which were positively associated with each other. Theme identification and eye gaze appear to be useful as tools for the objective measurement of abstract thinking in patients with schizophrenia.
    Behavioral and Brain Functions 04/2014; 10(1):13. DOI:10.1186/1744-9081-10-13 · 1.97 Impact Factor
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    • "Impairments in executive functioning are considered a primary deficit in schizophrenia. They occur early in the course of the disorder (Rund et al., 2007; Faerden et al., 2009; Liu et al., 2011) and are "
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    ABSTRACT: Background: The goal of this study was to investigate differences in executive functioning between patients with early-onset and adult-onset schizophrenia spectrum psychoses at the time of first treatment. Methods: Neuropsychological tests covering executive functioning domains were performed for 20 adolescents with early-onset schizophrenia (EOS) close to first treatment and 90 first episode patients with adult onset schizophrenia (AOS) in addition to 66 adolescent- and 127 adult age and gender matched healthy controls. Results: Both EOS and AOS patients had significantly poorer executive performance than their age- and gender matched healthy counterparts. Both healthy adolescent controls and EOS patients had poorer executive performance than their adult counterparts. However, there were no differences in executive functioning between EOS and AOS patients after controlling for the levels of their age matched healthy control groups. Substituting EOS/AOS status with other age-at-onset thresholds had no effect. Conclusions: We find the same relative levels of executive dysfunction in EOS- and AOS groups at the time of first treatment. This does not necessarily contradict previous findings of more severe dysfunction in EOS patients over time, but indicates an interaction between the disorder and the maturational processes that only can be investigated through longitudinal studies.
    Schizophrenia Research 10/2012; 142(1-3). DOI:10.1016/j.schres.2012.10.006 · 3.92 Impact Factor
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