many children with learning disorders ( ld ) are mistakenly considered as having intellectual weakness resulting in missing appropriate treatment .
however , the intelligence is regarded as one of the prognostic factors in learning disorders ; thus , studying the children with learning disorders in terms of intelligence is necessary .
wechsler intelligence scale for children - fourth edition ( wisc - iv ) is one of the most important tests for measuring the intelligence in children .
wechsler intelligence scale is one of the oldest methods for the determination of intelligence in children .
wisc - iv is the result of a combination of some verbal comprehension , perceptual reasoning , working memory , processing speed , and full intelligence scales . in this test , those who are below the average range in cognitive abilities are in a lower level than their peers in reasoning , thinking and understanding abilities and should be followed up through therapeutic interventions .
cas objective is to measure the basic processes of individual capabilities known as cognitive processes of pass ( planning , attention , simultaneous , successive ) that are the basics of human intelligence function .
both of the tests have been previously translated into persian by iranian researchers and the validity and reliability of the persian versions have been evaluated .
although the persian version of both wisc - iv and cas tests are used for determining intelligence coefficient in patients with ld , however , there is no documented correlation between their results .
this study aimed to compare the persian version of the two tests , to determine the correlation among their scales and to evaluate the probable concurrent validity of these tests in patients with learning disorders .
all children aged 6 to 15 years with suspected learning disorders who were presented at atieh comprehensive psychiatry center , tehran , from may till august 2010 were selected in a consecutive non - randomized order ; the patients were examined by a single psychiatrist and those with documented disease were enrolled in a cross - sectional study .
not having any neurological and psychiatric disorders and not taking any other medication were considered as the inclusion criteria .
all of the patients were assessed based on wisc - iv and cas scores questionnaires .
wisc - iv test performance requires constant cooperation of the subjects and examiner during the test ; the test consists of two practical and verbal parts .
each of the practical and verbal intelligence scales consist of several subscales . to run the test , it was necessary that the subjects and the examiner sit behind a table in front of each other . in most of the subscales ,
the runtime is critical making the use of a stopwatch and recording the exact time necessary .
some scales of the test such as similarity section were performed verbally ; for example the subjects were asked to express the similarity between two words or two things .
practical parts included performances such as encryption , in which the subjects were asked to place some learnt symbols into the blank places of various shapes using a pencil . during the test implementation
it was tried to set the location of running test in a standard and good condition regarding ventilation , light , complete silence and proper table height .
this time could be slightly less or more than usual according to the responses of the subjects .
if due to the subject tiredness it was needed to postpone a part of the test to another time , the next session would not be set after more than a week interval .
each sub - tests of wechsler intelligence scale have a specific instruction for correcting and grading . generally , grading of the tests , such as encryption and calculating was very simple but others , such as grading vocabulary capacity and similarities depended on the examiner 's ability to evaluate and judge .
after calculating the crude scores , the balance scores were calculated using tables designed according to specific age groups and the subjects practical , verbal and total iq scores were assessed using tables .
this test has been translated to persian , adapted and standardized by abedi et al .
the cas test was conducted using pen and paper method by cooperation of the subject and the examiner during the test .
the runtime was usually considered 1.5 hours and , with respect to how the subject responded , the test duration could be modified up to 15 minutes more or less . some subscales such as a pairing the numbers were practically performed by the subjects ; for example in pairing the numbers , the subjects were asked to circle around two identical numbers in each line .
other fields such as phrases repetitions were performed verbally ; the subject is provided with sentences starting with easy phrases and ending in complex ones and he / she must take the sentences in mind and repeat the exact phrases . because of scales such as planning and attention , which reflect the problems such as attention deficit hyperactive disorders ( adhd ) , the patient was recommended not to use narcotic -containing drugs such as codeine and also hyperactivity associated drugs such as ritalin before running the test .
cas test has two separate forms , specified for ages of 5 - 7 years and 8 - 17 years which are performed with respect to the exact age of the subjects .
the test is composed of four scales of planning , attention , simultaneous , and successive ; the crude score of each scale was obtained by adding the scores of the sub - scales . after putting the scores on the scale score tables which are prepared based on different ages , the final scores of the scales were obtained .
the sample size of our study was calculated as 162 cases regarding a correlation coefficient of 0.71 between the wechsler intelligence test and cas test total scores obtained in previous studies and an estimated precision of 0.07 .
pearson correlation coefficient was used to analyze the correlation among the data and to assess the concurrent validity of the two tests .
a total of 162 children suffering from ld with a mean age of 9.072.068 were recruited in the study during april to august 2010 .
the minimum age was 6 years and the maximum was 15 years old , of which 111 ( 68.5% ) cases were males and 51 ( 31.5% ) females . considering education level , 123 ( 75.9% ) of the children were in the first grade , 32 ( 19.8% ) in the second grade , 6 ( 3.7% ) in the third grade and one ( 0.6% ) in the fourth grade of primary school .
the data for wechsler intelligence test - fourth edition ( wisc - iv ) and cognitive assessment system ( cas ) were analyzed .
the mean and standard deviation for the subscales of wisc - iv and cas are presented in table 1 . 
 
the mean and standard deviation for the scales of wechsler intelligence test fourth edition ( wisc - iv ) and cognitive assessment system pearson correlation showed that there was a significant positive correlation between verbal scale of wisc - iv and planning scale of cas system ( r=0.457 ) .
there was also significant correlation between verbal intelligence and simultaneous processes scales ( r=0.632 ) , between verbal intelligence scale and attention scale of cas ( r=0.430 ) , between verbal intelligence and successive processes scales ( 0.551 ) and between verbal intelligence scale of wisc - iv and total score of cas test ( r=0.573 ) ( table 2 ) . 
 
the correlation between wechsler intelligence test fourth edition ( wisc - iv ) and cognitive assessment system scales p<0.001 in all correlations pearson correlation also showed that there was a significant correlation between perceptual intelligence and planning scales ( r=0.583 ) , between perceptual intelligence scale and simultaneous processes scale ( r=0.776 ) , between successive processes scale ( r=0.450 ) and between perceptual intelligence scale and total score of cas test ( r=0.695 ) ( table 2 ) .
pearson correlation indicated a significant correlation between working memory scale of wisc - iv and planning scale ( r=0.571 ) , between working memory scale of wisc - iv and simultaneous processes scale ( r=0.635 ) , between working memory and attention scales ( 0.544 ) , between working memory and successive processes scales ( r=0.689 ) and between working memory scale and total score of cas test ( r=0.665 ) ( table 2 ) .
pearson correlation also stated a significant correlation between information processing scale of wisc - iv and planning scale ( r=0.646 ) , between information processing scale of intelligence and simultaneous processes scale ( r=0.550 ) , between information processing scale and attention scale ( 0.668 ) , between information processing and successive processes scales ( r=0.315 ) and between information processing scale and total score of cas test ( r=0.625 ) ( table 2 ) .
besides , there was a significant correlation between full intelligence score of wisc - iv test and planning scale of cas test ( r=0.637 ) , between full intelligence score of wisc - iv test and simultaneous processes scale of cas test ( r=0.773 ) , between full intelligence score of wisc - iv test and attention scale of cas test ( 0.627 ) , between full intelligence score of wisc - iv test and successive processes scale of cas test ( r=0.617 ) and between full intelligence score of wisc - iv test and total score of cas test ( r=0.750 ) ( table 2 ) . considering intelligence score as the independent variable and cas test score as dependent variable in a linear regression model , a significant model was obtained for which the results are as follows :  = 0.51 ,  = 0.81 and p < 0.001 .
this study showed that there was a strong correlation between total score of wisc - iv test and total score of cas test in these patients ( r=0.75 , p<0.001 ) .
the study of the correlations among the other scales of these two tests which are all statistically significant ( p<0.001 ) gives valuable information . on the other hand ,
considering the score of wechsler test as the independent variable and cas test score as the dependent variable in a linear regression model between total score of these two tests , a significant model was obtained (  = 0.51 ,  = 0.81 , p<0.001 ) .
thus , we can generally conclude that there is a concurrent validity between total score of wisc - iv test and total score of cas test and also among the scales of these two tests .
learning disorders are born due to poor functioning of the brain and can influence the individual mental processes such as word recognition , memory , reading comprehension , auditory language processing and mathematical analysis .
learning disorders can also be associated with different types of adhd , behavioral disorders and sensory disabilities . since 1905 , binet 's intelligence scales were considered as the preferred tests . the weaknesses of binet 's scales led wechsler to provide new intelligence scales ; the latest in children were called wisc - iii and wisc - iv . on the other hand ,
there have been efforts in the recent years to provide tests that follow the new knowledge of psychology .
these tests are based on approaches that study intelligence as a group of cognitive processes .
cas test was developed and reviewed in the mid - nineties by naglieri and colleagues and applied in 2200 american children aged 5 - 17 years who were categorized according to age , sex , race and ethnicity , geographic region , educational status and parental education .
it is an appropriate alternative to the conventional intelligence tests 

  cas test is a test with high validity in structure , prediction and content .
the theory of pass is a useful method for evaluating and understanding the cognitive function .
taddei and his co - worker tried to examine differences between children with adhd and specific learning disabilities based on cognitive function using wisc and cas .
validity analyses are the best methods for assessing translated version of questionnaires . in other hand , evaluating concurrent validity between tests is common and has been performed in many studies .
the correlation and validity of these two tests have been previously investigated in a number of studies ; our study confirmed their results .
feiz et al in a study which was conducted in the present center during last year , evaluated the correlation between wechsler intelligence test- third edition and the cas test among 100 children aged 5 - 16 years who were referred for further investigations to this specialized clinic using a persian questionnaire .
the correlations among all scales of these tests were significant and the correlation between mathematical analysis scale of wechsler test and all scales of cas test was significant . in a study conducted by naglieri et al ,
the correlation between wechsler intelligence test ( third edition ) and cognitive assessment system with woodcock - johnson tests of achievement ( wj - iii ) was assessed in a sample of 119 children aged 6 to 16 years .
the survey results showed the validity of the cas test in investigating the general intelligence of wechsler ( third edition ) test 

  in another study conducted by naglieri et al , two matched groups of 25 children with adhd and anxiety / depression disorders were studied using wechsler tests ( third edition ) and cas and then were compared with those parameters in normal population .
the findings showed that wechsler test differentiated the samples to a few level while the cas test scales were sensitive to cognitive processing problems in children with adhd .
we suggest other researchers to conduct similar studies via prospective longitudinal ones with larger sample size .
in this study , an acceptable correlation was observed between the wisc - iv scales and cas test in children with learning disorders ; hence , it can be concluded that a concurrent validity is established between the two tests and their scales .
 objectivethe aim of this study was to compare the persian version of the wechsler intelligence scale for children - fourth edition ( wisc - iv ) and cognitive assessment system ( cas ) tests , to determine the correlation between their scales and to evaluate the probable concurrent validity of these tests in patients with learning disorders.methodsone-hundered-sixty-two children with learning disorder who were presented at atieh comprehensive psychiatry center were selected in a consecutive non - randomized order . 
 all of the patients were assessed based on wisc - iv and cas scores questionnaires . 
 pearson correlation coefficient was used to analyze the correlation between the data and to assess the concurrent validity of the two tests . 
 linear regression was used for statistical modeling . 
 the type one error was considered 5% in maximum.findingsthere was a strong correlation between total score of wisc - iv test and total score of cas test in the patients ( r=0.75 , p<0.001 ) . 
 the correlations among the other scales were mostly high and all of them were statistically significant ( p<0.001 ) . 
 a linear regression model was obtained (  = 0.51 ,  = 0.81 and p<0.001).conclusionthere is an acceptable correlation between the wisc - iv scales and cas test in children with learning disorders . 
 a concurrent validity is established between the two tests and their scales . 
Introduction
Subjects and Methods
Findings
Discussion
Conclusion
Conflict of Interest