Are children with ADHD predominantly inattentive and combined subtypes different in terms of aspects of everyday attention?

The validity of the DSM-IV subtypes is a recurring diagnostic debate in attention deficit/hyperactivity disorder (ADHD). Laboratory measures, such as the test of everyday attention for children (TEA-Ch) can help us address this question. TEA-Ch is a test battery covering different aspects of everyday attention relating to selective and sustained attention and attentional control. The aim of the current study was to investigate whether this instrument can differentiate between combined (ADHD-C) and inattentive subtype (ADHD-I) of ADHD. Subjects were recruited from a multidisciplinary ADHD outpatient unit and tested free of medication. Sixty-four children with a diagnosis of ADHD were included (38 with ADHD-C; 26 with ADHD-I). The control group was 76 children recruited from primary and secondary schools. Children with ADHD performed worse than controls on 6 out of 9 TEA-Ch subtests. However a regression analysis revealed that TEA-Ch subtests made only a marginal contribution to the correct classification of ADHD, once the effects of IQ and age are controlled. Confirmatory factor analysis in our ADHD group demonstrated that the three factor structure achieved a poor fit. More detailed analysis suggested that inferior performance on the tasks designed to test vigilance was not the result of deficient-sustained attention. ADHD-C and ADHD-I showed very few differences across tasks. In conclusion, our results provided not much support for the value of the ADHD-C and ADHD-I distinction in predicting difficulties in everyday attention.