DIFFERENCES OF ATTENTIONAL FUNCTIONS BETWEEN PATIENTS WITH ATTENTION-DEFICIT/HYPERACTIVITY DISORDER (AD/HD) AND THOSE WITH PERVASIVE DEVELOPMENTAL DISORDERS (PDD)

Objective: Patients with PDD often show the symptoms of inattention and/or hyperactivity-impulsiveness similar to those of AD/HD, especially in their early school years, which makes it somewhat difficult and confusing to differentiate them. In this study, we investigate whether it is possible or not to differentiate patients with PDD from those with AD/HD in terms of the profiles of their attentional functions.

Methods: Eleven school-aged children with AD/HD and 11 with PDD, diagnosed with DSM-IV, were involved in this study. AD/HD group had all males but one with 8.6±1.4 years of age and the mean FIQ by WISC-III 106 (92˜125). All of them, except one with inattention subtype, had combined subtype. PDD group had all males with 9.0±1.8 years of age and the mean FIQ 103 (88˜132). A group-administered test battery purported to assess a range of attentional functions, including selective attention, sustained attention, response inhibition and divided attention developed by Imada et al (2003) was performed on each group at the same time in the morning without any medication, including methylphenidate.

Results: AD/HD group showed lower scores in sustained attention (p<.10) and response inhibition (p<.05) compared with PDD group. Dual task testing on divided attention revealed marked differences between the two. AD/HD group showed remarkable improvement of both selective (p<.05) and sustained (p<.01) attention in the dual task condition compared with the single task condition, whereas PDD group showed improvement only in the selective attention (p<.05).

Conclusion: It was found that the children with PDD had different profiles of attentional functions from those with AD/HD. Therefore, it might be possible to differentiate them in terms of the attentional functions.