[Nocturnal polysomnographic study in children with attention deficit hyperactivity disorder].

INTRODUCTION: The main symptoms of attention deficit hyperactivity disorder (ADHD) are attention deficit, hyperactivity and impulsivity. Its prevalence lies between 3 and 5% in schoolchildren. Children with ADHD can present a high prevalence rate of comorbidity. A timely diagnosis and treatment can modify the educational and psychosocial development of most of these children. A number of subjective reports (especially from parents) describe sleep disorders. The objective verification of these disorders and the exact nature of the sleep problems are still to be determined and the purpose of this study is to deal with these issues.

PATIENTS AND METHODS: We studied a sample of 48 children (9 females and 39 males) with a mean age of 8 (SD: 2.59) who met DSM IV criteria. They were submitted to a general exploration as well as a neurological exploration, including their patient record, and then they were evaluated using the DSM IV, which was carried out by parents and teachers (in order to evaluate two different environments), and a nocturnal polysomnographic study. In the sample there were 26 children with predominant attention deficit type ADHD (ADHD/AD); 4 children with predominant hyperactivity impulsivity type ADHD (ADHD/H); and 18 children with combined type ADHD (ADHD/C).

RESULTS: The most frequently diagnosed subtype is the attention deficit subtype. The sleep architecture of children with ADHD presents the most consistent differences as compared to normal children in an increase in the percentage of phase 3 of sleep and, consequently, an increase in the percentage of slow sleep. Epileptiform type paroxysms were observed in 16.7% of the children who presented symptoms of ADHD. The number of epileptiform paroxysms is more usual in the attention deficit subtype.

CONCLUSIONS: The increase in phase 3 may be related to the alterations in noradrenaline and dopamine transmission present in children who suffer from ADHD. Some children with ADHD can have a region of the brain with intense epileptic activity, which does not trigger epileptic seizures but gives rise to behavioural disorders, learning disorders and language problems.