Introduction: Test of Variables of Attention (TOVA) is used as a diagnostic tool in the assesment of Attention-Deficit/Hyperactivity Disorder (ADHD) and Attention Deficit Disorder (ADD). Existing literature suggests that intelligence may influence performance on TOVA, however research on this topic is limited. The purpose of this study was to identify whether there exists a correlation between Full Scale Intelligence Quotient (FSIQ) and TOVA scores among children with ADHD or ADD. A second aim was to investigate if IQ index scores correlated with TOVA scores in the same group of children.

Methods: Hospital records of children aged six to 17 years with ADHD or ADD who attended the Department of Child and Adolescent psychiatry, Aalborg University Hospital from 1st June 2014 to 31st May 2015 were collected. To be included, the child had to have completed both an intelligence test and a TOVA test. Data were analyzed using descriptive statistics, Pearson’s correlation test and Kruskal Wallis test.

Results: The sample comprised 75 children. There were significant correlations between FSIQ and all TOVA variables except from response time (RT). Additionally, IQ index scores correlated with some of the TOVA variables as well. Correlations were positively associated and weak to moderate in strength. Significant differences in some TOVA variables were demonstrated when children were grouped according to IQ.

Discussion and conclusion: Intellectual functioning significantly influenced TOVA performance. Children with low IQ performed significantly poorer than children with high IQ of whom some despite ADHD/ADD passed the TOVA test. This questions sensitivity and specificity of the test. A small sample size, no appropriate control group and lack of a limited time span between conduction of the intelligence- and TOVA test impaired results, thus results must be interpreted with caution.