Brief Assessment of Cognition in Schizophrenia: Validation of the Japanese version

Abstract

This preliminary study was performed to test the reliability and validity of the Brief Assessment of Cognition in Schizophrenia (BACS) as an assessment tool in a Japanese-language version (BACS-J). The subjects for the present study were 30 outpatients with chronic schizophrenia. Each subject gave written informed consent to participate in the research. Cronbach's alpha for the BACS-J was 0.77. The BACS-J composite score was significantly correlated with all primary measures of BACS-J (verbal memory, working memory, motor speed, verbal fluency, attention, and executive function). All BACS-J primary measures and the composite score were significantly correlated between two assessments. The mean score of the Digit Sequencing Task and composite score on the second assessment were significantly larger than those on the first assessment. All BACS-J primary measures except the Symbol Coding Task were significantly correlated with relevant standard neurocognitive tests. Also, the BACS-J composite score was significantly correlated with all standard neurocognitive tests except the Continuous Performance Test. A principal components analysis with varimax rotation resulted in a three-factor solution (executive function and memory; motor speed and general cognitive functions; and working memory). This preliminary study indicates that the BACS-J is a reliable and practical scale to evaluate cognitive function.

Serotonin-1A Receptors and Cognitive Enhancement in Schizophrenia: Role for Brain Energy Metabolism

“…In particular, the Measurement and Treatment Research to Improve Cognition in Schizophrenia (MATRICS) Consensus Cognitive Battery (Nuechterlein et al 2008) (Fig 1) and the Brief Assessment of Cognition in Schizophrenia (BACS) (Keefe et al 2004) (Fig 2) are regarded to be qualified as international-standard neuropsychological tools in this respect. The authors have developed the Japanese versions of these cognitive test batteries (Kaneda et al 2007, Sato et al 2010, and have confirmed their sensitivity and validity to detect cognitive deficits in patients (Fig 3). …”

Cognitive impairments in psychotic disorders: common mechanisms and measurement

“…The growing research on other methods for assessing cognitive function (e.g., self-report, clinician interview) suggests that they have limited correlation with objective measures of cognitive performance (137), though they may still have utility in predicting functional status (137)(138)(139)(140)(141)(142)(143)(144). If a formal assessment of cognition is not possible, it is still important for the clinician to use the best available information to make a judgment about the individual's cognitive function, including the clinician's interactions with the patient and/or reports of family members or clinical staff.…”

Relationship between Cognitive Function and Employment in Japanese Schizophrenia Patients

“…The domains of cognitive function that are evaluated by the BACS are verbal memory (list learning), working memory (digit sequencing task), motor speed (token motor task), verbal fluency (category instances and controlled oral word association test), attention and speed of information processing (symbol coding), and executive function (tower of London). It was reported that the Japanese version of it was a reliable and practical scale to evaluate cognitive function in schizophrenia patients [12]. In the present study, the BACS data were collected by clinical psychologists who were very experienced and well trained for the use of it.…”

“…On the other hand, several recent studies have showed that positive and negative symptoms might be more important than cognitive function with regard to functional outcome and employment [7] [8]. As for Japanese patients, previous research reported that cognitive function of Japanese schizophrenia patients showed a score of one to two orders below that of healthy controls in several cognitive dimensions, particularly verbal memory, working memory, motor speed, verbal fluency, attention and speed of information processing, and executive function [9]. There has been evidence of relationships between cognitive function and clinical symptom [10] or quality of life [11].…”