Psychiatry and Clinical Neurosciences 2014; 68: 160–166
doi:10.1111/pcn.12107
Regular Article
Validation of the Persian version of the Brief Assessment of Cognition in Schizophrenia in patients with schizophrenia and healthy controls Shahrzad Mazhari, MD, PhD,1* Nooshin Parvaresh, MD,1 Mahin Eslami Shahrbabaki, Mohammad M. Sadeghi, MD,1 Nouzar Nakhaee, MD1 and Richard S. E. Keefe, PhD2
MD,1
1 Neuroscience Research Center, Kerman University of Medical Sciences, Kerman, Iran, and 2Department of Psychiatry, Duke University Medical Center, North Carolina, USA
Aims: The Brief Assessment of Cognition in Schizophrenia (BACS) is designed for assessment of cognitive function in patients with schizophrenia. Versions of the BACS in English and other languages have been shown to be as sensitive to cognitive dysfunction as a standard test battery, with the advantage of brief administration and scoring time. The present study aimed to test the concurrent validity of the Persian version of the BACS (Persian-BACS). Methods: A group of 50 patients with schizophreniaspectrum disorders and a group of 50 healthy controls received the Persian-BACS in a first session, and in a second session a standard neurocognitive battery. Results: Cronbach’s alpha for the Persian-BACS was 0.74. All the Persian-BACS subscales were
N THE LATE 19th century, German psychiatrist Emil Kraepelin described a chronic and deteriorating psychotic disorder associated with cognitive disintegration, termed dementia praecox (meaning early dementia). Afterwards, however, Eugen Bleuler replaced the term dementia praecox with ‘schizophrenia’. Since then, schizophrenia has been defined
I
*Correspondence: Shahrzad Mazhari, MD, PhD, Neuroscience Research Center, Kerman University of Medical Sciences, Somayeh Cross, In Front of Besat Clinic, P.O. Box: 76175-113, Kerman, Iran. Email: [email protected] Received 26 April 2013; revised 3 July 2013; accepted 6 August 2013.
160
significantly correlated with the corresponding standard neurocognitive subscales and the Pearson correlation of the composite scores from the two instruments was 0.71. Moreover, a one-factor solution was found that accounted for 67.9% of the variance. Finally, the Persian-BACS demonstrated high ability to discriminate patients with schizophrenia from healthy controls.
Conclusion: Good psychometric properties of the Persian-BACS suggest that it is a useful tool for assessing cognition in schizophrenic patients with Persian as their primary language. Key words: Brief Assessment of Cognition in Schizophrenia, cognition, Persian, schizophrenia.
mainly by its symptomatology, apart from cognitive dysfunction. Nevertheless, in recent decades, there has been great attention paid to the pattern of cognitive dysfunction in patients with schizophrenia, and it has been considered as a core feature of the disorder.1 A wide variety of methods and tests has been used to examine the pattern of cognitive abilities of patients with schizophrenia. The cognitive performances of patients with schizophrenia are 1.5–2.0 SD below healthy controls on a range of neurocognitive tasks, including verbal memory, verbal fluency, working memory, motor speed, attention, and executive function.2 Furthermore, cognitive deficits may be a cause of poor social and occupational dysfunction,3–6 as well as of impaired decisional capacity in patients.7
© 2013 The Authors Psychiatry and Clinical Neurosciences © 2013 Japanese Society of Psychiatry and Neurology
Psychiatry and Clinical Neurosciences 2014; 68: 160–166
Persian version of the BACS 161
Consequently, cognitive deficits have been recognized as an important treatment goal for patients with schizophrenia. In order to assess cognitive function in patients with schizophrenia, several neurocognitive assessment batteries have been developed. However, most of them are long and require several hours to administer, are expensive, and are unavailable in most practice settings. Moreover, clinicians’ lack of familiarity with psychometric administration procedures and interpretation limits their capacity to use many comprehensive neurocognitive assessment batteries. Therefore, it is of great interest to develop an easily used battery of validate tests in patients with schizophrenia. The assessment battery should be portable, cover relevant cognitive domains, have a brief administration time, and have good sensitivity and test–retest reliability.8 To address these needs, Keefe et al. (2004) developed a pen-and-paper battery of neurocognitive tests referred to as the Brief Assessment of Cognition in Schizophrenia (BACS).8 The BACS is specifically designed for assessment of cognitive function in schizophrenia and has several advantages, including brief administration (approximately 35 min) and scoring time, portability, repeatability and availability of alternative forms. Importantly, the BACS can be administered by a wide range of mental health professionals like psychiatrists, neurologists, psychologists, and psychiatric nurses. The English BACS has eight alternative versions of the verbal memory test and two alternative versions of the reasoning and problemsolving test. It assesses the cognitive domains found to be consistently impaired and closely related to outcome in schizophrenia, including verbal memory, verbal fluency, working memory, motor speed, attention, and executive function.8,9 So far, the BACS has been translated into 30 different languages, and validated in several of these, including Spanish,10 French,11 Japanese,12 Italian,13 Brazilian,14 and German.15 These versions have shown acceptable reliability and concurrent validity with a standard cognitive battery, which takes more than 2 h to administer. The aim of the present study was to assess the concurrent validity of a Persian version of the BACS (Persian-BACS), using correlation analysis between the Persian-BACS and a standard neurocognitive battery. Persian is the 13th most spoken language in the world, and more than 110 million people around the world speak the Persian language. Importantly, none of the neurocognitive
assessment batteries used in schizophrenia studies have been translated and validated into Persian language. Therefore, adaptation and validation of the BACS into the Persian language would help the research of cognition in schizophrenia for Persianspeaking people, as well as facilitating studies of cultural effects on cognitive performance in schizophrenia patients.16
METHODS Participants A group of 50 Persian-speaking patients (30 male) was recruited from inpatients and outpatients of two psychiatric hospitals in Kerman, Iran. All patients met DSM-IV criteria for a lifetime diagnosis of schizophrenia or schizoaffective disorder. At the time of testing, patients were receiving antipsychotic medication and were clinically stable. The mean chlorpromazine equivalent was 331.5 (SD = 179.4) mg.17 The control group comprised 50 healthy participants (25 male) screened for a personal or family history of psychotic illnesses. Exclusion criteria for all participants included head injury, neurological disorder, and substance abuse treatment at the time of testing. Written informed consent was obtained from all participants. The study was approved by the Ethics Committees of Kerman University of Medical Sciences.
Persian adaptation procedure The standard forward–backward method was applied to translate the BACS from English into Persian.18 At first, the two versions of the BACS (A, B) were translated into Persian by two Iranian psychiatrists. These Persian versions were then back-translated into English by two independent translators, bilingual in Persian and English language, who were blind to the original English versions. No significant problematic issues in translation were encountered. All the stimulus items were preserved in the Persian adaptation. Finally, these back-translated versions were checked and approved by the original author (R.S.E.K.).
Assessment procedures All the participants were tested using the PersianBACS and the standard neurocognitive battery of tests on two separate days, over a maximum period of 1
© 2013 The Authors Psychiatry and Clinical Neurosciences © 2013 Japanese Society of Psychiatry and Neurology
162 S. Mazhari et al.
Psychiatry and Clinical Neurosciences 2014; 68: 160–166
week. Participants received the Persian-BACS in the first test session, and the standard battery in the second session. The standard neurocognitive battery included the Rey Auditory–Verbal Learning Test (RAVLT),19 the Wechsler Adult Intelligence Scale (WAIS)-III Digit Symbol-Coding, Backward Digit Span and Arithmetic from the WAIS III,20 Controlled Oral Word Association Test (COWAT),21 Trailmaking Test (TMT) A and B,22 and the Wisconsin Card Sorting Test (WCST) 128 card version.23
with varimax rotation. Finally, sensitivity and specificity were determined using receiver–operator curve (ROC), with all patients coded as ‘cases’ and all controls as ‘non-cases’. All statistical tests were carried out using SPSS 17.0 (SPSS, Chicago, IL, USA), with a significance threshold of P < 0.05.
Data analysis Demographic data were compared between the two groups by using a combination of χ2-test and independent t-tests. Cronbach’s alpha was used to determine the internal consistency of the Persian-BACS. The composite scores of Persian-BACS and the standard neurocognitive battery were calculated by averaging all the subscales in each instrument, after transforming them into z scores. Concurrent validity of the Persian-BACS subscales was tested by using Pearson correlations with the corresponding scales of the standard battery. Particularly, Verbal memory (BACS Verbal memory with RAVLT [total learning trials]); Working memory (BACS Digit sequencing with WAIS-III Arithmetic and backward digit span); Verbal fluency (BACS Verbal fluency with COWAT); Speed of information processing (BACS Symbol Coding with WAIS-III Digit Symbol-Coding); Motor Speed (BACS Token Motor Task with TMT A [seconds]); and Executive functions (BACS Tower of London with WCST [total errors] and Trail-making B [seconds]). The factor structure of the scores was determined by using a principal components analysis
RESULTS Table 1 shows demographic and clinical characteristics for the participants. While the two groups were well matched for age, sex, and hand preference, the patient group had significantly fewer years of education than controls. Table 2 lists means and SD for all the BACS subscales for both groups. Patients had significantly lower scores relative to controls on all the BACS subscales, all P = 0.001 (Table 2). The time required to administer the Persian-BACS was 39.7 ± 8.4 (mean ± SD) min for patients and 31.5 ± 6.7 (mean ± SD) min for controls.
Reliability The BACS subscales demonstrated high internal consistency; Cronbach’s alpha was 0.74 in the patient group and 0.72 in the controls. Table 3 shows the intercorrelations between the BACS subscales and with the composite score in patients with schizophrenia. As expected, significant correlations were found between all of the BACS subscales (moderate to strong), with the exception of the correlations of verbal memory with the Token Motor Task and the Tower of London, and the correlation of the Token Motor Task with digit sequencing.
Table 1. Demographic and clinical characteristics of the study participants
Age Education Sex- n (% male)† Right hand preference Length of illness (years) Age at onset (years) Mean chlorpromazine equivalent (mg)
Patients n = 50
Controls n = 50
P-value
40.5 ± 10.6 10.2 ± 2.9 30 (60%) 46 (92%) 15.4 ± 9.3 25.1 ± 9.5 331.5 ± 179.4
37.3 ± 9.2 11.9 ± 3.2 25 (50%) 48 (96%) – – –
NS 0.005 NS NS – – –
χ -test. NS, not significant.
† 2
© 2013 The Authors Psychiatry and Clinical Neurosciences © 2013 Japanese Society of Psychiatry and Neurology
Psychiatry and Clinical Neurosciences 2014; 68: 160–166
Persian version of the BACS 163
Table 2. Means, z-scores and SD of the Persian-BACS subscales of the participants BACS subscales
Patients Mean
Patients z-score
Controls Mean
P-value
VM DS TM VF SC TL
31.9 ± 7.6 10.4 ± 5.2 48.8 ± 14.5 28.7 ± 11 15.7 ± 10.9 3.8 ± 5.1
−0.61 ± 0.69 −0.56 ± 0.96 −0.71 ± 0.70 −0.50 ± 0.86 −0.76 ± 0.61 −0.61 ± 0.79
45.2 ± 9.5 16.5 ± 3.6 78.5 ± 14.2 41.7 ± 11.3 42.9 ± 11.7 11.8 ± 5.2
doi:10.1111/pcn.12107
Regular Article
Validation of the Persian version of the Brief Assessment of Cognition in Schizophrenia in patients with schizophrenia and healthy controls Shahrzad Mazhari, MD, PhD,1* Nooshin Parvaresh, MD,1 Mahin Eslami Shahrbabaki, Mohammad M. Sadeghi, MD,1 Nouzar Nakhaee, MD1 and Richard S. E. Keefe, PhD2
MD,1
1 Neuroscience Research Center, Kerman University of Medical Sciences, Kerman, Iran, and 2Department of Psychiatry, Duke University Medical Center, North Carolina, USA
Aims: The Brief Assessment of Cognition in Schizophrenia (BACS) is designed for assessment of cognitive function in patients with schizophrenia. Versions of the BACS in English and other languages have been shown to be as sensitive to cognitive dysfunction as a standard test battery, with the advantage of brief administration and scoring time. The present study aimed to test the concurrent validity of the Persian version of the BACS (Persian-BACS). Methods: A group of 50 patients with schizophreniaspectrum disorders and a group of 50 healthy controls received the Persian-BACS in a first session, and in a second session a standard neurocognitive battery. Results: Cronbach’s alpha for the Persian-BACS was 0.74. All the Persian-BACS subscales were
N THE LATE 19th century, German psychiatrist Emil Kraepelin described a chronic and deteriorating psychotic disorder associated with cognitive disintegration, termed dementia praecox (meaning early dementia). Afterwards, however, Eugen Bleuler replaced the term dementia praecox with ‘schizophrenia’. Since then, schizophrenia has been defined
I
*Correspondence: Shahrzad Mazhari, MD, PhD, Neuroscience Research Center, Kerman University of Medical Sciences, Somayeh Cross, In Front of Besat Clinic, P.O. Box: 76175-113, Kerman, Iran. Email: [email protected] Received 26 April 2013; revised 3 July 2013; accepted 6 August 2013.
160
significantly correlated with the corresponding standard neurocognitive subscales and the Pearson correlation of the composite scores from the two instruments was 0.71. Moreover, a one-factor solution was found that accounted for 67.9% of the variance. Finally, the Persian-BACS demonstrated high ability to discriminate patients with schizophrenia from healthy controls.
Conclusion: Good psychometric properties of the Persian-BACS suggest that it is a useful tool for assessing cognition in schizophrenic patients with Persian as their primary language. Key words: Brief Assessment of Cognition in Schizophrenia, cognition, Persian, schizophrenia.
mainly by its symptomatology, apart from cognitive dysfunction. Nevertheless, in recent decades, there has been great attention paid to the pattern of cognitive dysfunction in patients with schizophrenia, and it has been considered as a core feature of the disorder.1 A wide variety of methods and tests has been used to examine the pattern of cognitive abilities of patients with schizophrenia. The cognitive performances of patients with schizophrenia are 1.5–2.0 SD below healthy controls on a range of neurocognitive tasks, including verbal memory, verbal fluency, working memory, motor speed, attention, and executive function.2 Furthermore, cognitive deficits may be a cause of poor social and occupational dysfunction,3–6 as well as of impaired decisional capacity in patients.7
© 2013 The Authors Psychiatry and Clinical Neurosciences © 2013 Japanese Society of Psychiatry and Neurology
Psychiatry and Clinical Neurosciences 2014; 68: 160–166
Persian version of the BACS 161
Consequently, cognitive deficits have been recognized as an important treatment goal for patients with schizophrenia. In order to assess cognitive function in patients with schizophrenia, several neurocognitive assessment batteries have been developed. However, most of them are long and require several hours to administer, are expensive, and are unavailable in most practice settings. Moreover, clinicians’ lack of familiarity with psychometric administration procedures and interpretation limits their capacity to use many comprehensive neurocognitive assessment batteries. Therefore, it is of great interest to develop an easily used battery of validate tests in patients with schizophrenia. The assessment battery should be portable, cover relevant cognitive domains, have a brief administration time, and have good sensitivity and test–retest reliability.8 To address these needs, Keefe et al. (2004) developed a pen-and-paper battery of neurocognitive tests referred to as the Brief Assessment of Cognition in Schizophrenia (BACS).8 The BACS is specifically designed for assessment of cognitive function in schizophrenia and has several advantages, including brief administration (approximately 35 min) and scoring time, portability, repeatability and availability of alternative forms. Importantly, the BACS can be administered by a wide range of mental health professionals like psychiatrists, neurologists, psychologists, and psychiatric nurses. The English BACS has eight alternative versions of the verbal memory test and two alternative versions of the reasoning and problemsolving test. It assesses the cognitive domains found to be consistently impaired and closely related to outcome in schizophrenia, including verbal memory, verbal fluency, working memory, motor speed, attention, and executive function.8,9 So far, the BACS has been translated into 30 different languages, and validated in several of these, including Spanish,10 French,11 Japanese,12 Italian,13 Brazilian,14 and German.15 These versions have shown acceptable reliability and concurrent validity with a standard cognitive battery, which takes more than 2 h to administer. The aim of the present study was to assess the concurrent validity of a Persian version of the BACS (Persian-BACS), using correlation analysis between the Persian-BACS and a standard neurocognitive battery. Persian is the 13th most spoken language in the world, and more than 110 million people around the world speak the Persian language. Importantly, none of the neurocognitive
assessment batteries used in schizophrenia studies have been translated and validated into Persian language. Therefore, adaptation and validation of the BACS into the Persian language would help the research of cognition in schizophrenia for Persianspeaking people, as well as facilitating studies of cultural effects on cognitive performance in schizophrenia patients.16
METHODS Participants A group of 50 Persian-speaking patients (30 male) was recruited from inpatients and outpatients of two psychiatric hospitals in Kerman, Iran. All patients met DSM-IV criteria for a lifetime diagnosis of schizophrenia or schizoaffective disorder. At the time of testing, patients were receiving antipsychotic medication and were clinically stable. The mean chlorpromazine equivalent was 331.5 (SD = 179.4) mg.17 The control group comprised 50 healthy participants (25 male) screened for a personal or family history of psychotic illnesses. Exclusion criteria for all participants included head injury, neurological disorder, and substance abuse treatment at the time of testing. Written informed consent was obtained from all participants. The study was approved by the Ethics Committees of Kerman University of Medical Sciences.
Persian adaptation procedure The standard forward–backward method was applied to translate the BACS from English into Persian.18 At first, the two versions of the BACS (A, B) were translated into Persian by two Iranian psychiatrists. These Persian versions were then back-translated into English by two independent translators, bilingual in Persian and English language, who were blind to the original English versions. No significant problematic issues in translation were encountered. All the stimulus items were preserved in the Persian adaptation. Finally, these back-translated versions were checked and approved by the original author (R.S.E.K.).
Assessment procedures All the participants were tested using the PersianBACS and the standard neurocognitive battery of tests on two separate days, over a maximum period of 1
© 2013 The Authors Psychiatry and Clinical Neurosciences © 2013 Japanese Society of Psychiatry and Neurology
162 S. Mazhari et al.
Psychiatry and Clinical Neurosciences 2014; 68: 160–166
week. Participants received the Persian-BACS in the first test session, and the standard battery in the second session. The standard neurocognitive battery included the Rey Auditory–Verbal Learning Test (RAVLT),19 the Wechsler Adult Intelligence Scale (WAIS)-III Digit Symbol-Coding, Backward Digit Span and Arithmetic from the WAIS III,20 Controlled Oral Word Association Test (COWAT),21 Trailmaking Test (TMT) A and B,22 and the Wisconsin Card Sorting Test (WCST) 128 card version.23
with varimax rotation. Finally, sensitivity and specificity were determined using receiver–operator curve (ROC), with all patients coded as ‘cases’ and all controls as ‘non-cases’. All statistical tests were carried out using SPSS 17.0 (SPSS, Chicago, IL, USA), with a significance threshold of P < 0.05.
Data analysis Demographic data were compared between the two groups by using a combination of χ2-test and independent t-tests. Cronbach’s alpha was used to determine the internal consistency of the Persian-BACS. The composite scores of Persian-BACS and the standard neurocognitive battery were calculated by averaging all the subscales in each instrument, after transforming them into z scores. Concurrent validity of the Persian-BACS subscales was tested by using Pearson correlations with the corresponding scales of the standard battery. Particularly, Verbal memory (BACS Verbal memory with RAVLT [total learning trials]); Working memory (BACS Digit sequencing with WAIS-III Arithmetic and backward digit span); Verbal fluency (BACS Verbal fluency with COWAT); Speed of information processing (BACS Symbol Coding with WAIS-III Digit Symbol-Coding); Motor Speed (BACS Token Motor Task with TMT A [seconds]); and Executive functions (BACS Tower of London with WCST [total errors] and Trail-making B [seconds]). The factor structure of the scores was determined by using a principal components analysis
RESULTS Table 1 shows demographic and clinical characteristics for the participants. While the two groups were well matched for age, sex, and hand preference, the patient group had significantly fewer years of education than controls. Table 2 lists means and SD for all the BACS subscales for both groups. Patients had significantly lower scores relative to controls on all the BACS subscales, all P = 0.001 (Table 2). The time required to administer the Persian-BACS was 39.7 ± 8.4 (mean ± SD) min for patients and 31.5 ± 6.7 (mean ± SD) min for controls.
Reliability The BACS subscales demonstrated high internal consistency; Cronbach’s alpha was 0.74 in the patient group and 0.72 in the controls. Table 3 shows the intercorrelations between the BACS subscales and with the composite score in patients with schizophrenia. As expected, significant correlations were found between all of the BACS subscales (moderate to strong), with the exception of the correlations of verbal memory with the Token Motor Task and the Tower of London, and the correlation of the Token Motor Task with digit sequencing.
Table 1. Demographic and clinical characteristics of the study participants
Age Education Sex- n (% male)† Right hand preference Length of illness (years) Age at onset (years) Mean chlorpromazine equivalent (mg)
Patients n = 50
Controls n = 50
P-value
40.5 ± 10.6 10.2 ± 2.9 30 (60%) 46 (92%) 15.4 ± 9.3 25.1 ± 9.5 331.5 ± 179.4
37.3 ± 9.2 11.9 ± 3.2 25 (50%) 48 (96%) – – –
NS 0.005 NS NS – – –
χ -test. NS, not significant.
† 2
© 2013 The Authors Psychiatry and Clinical Neurosciences © 2013 Japanese Society of Psychiatry and Neurology
Psychiatry and Clinical Neurosciences 2014; 68: 160–166
Persian version of the BACS 163
Table 2. Means, z-scores and SD of the Persian-BACS subscales of the participants BACS subscales
Patients Mean
Patients z-score
Controls Mean
P-value
VM DS TM VF SC TL
31.9 ± 7.6 10.4 ± 5.2 48.8 ± 14.5 28.7 ± 11 15.7 ± 10.9 3.8 ± 5.1
−0.61 ± 0.69 −0.56 ± 0.96 −0.71 ± 0.70 −0.50 ± 0.86 −0.76 ± 0.61 −0.61 ± 0.79
45.2 ± 9.5 16.5 ± 3.6 78.5 ± 14.2 41.7 ± 11.3 42.9 ± 11.7 11.8 ± 5.2
