Apnea-hypopnea indices and snoring in children diagnosed with ADHD: a matched case-control study
To measure apnea-hypopnea indices and snoring in children diagnosed with attention-deficit hyperactivity disorder (ADHD) in a case-control design. Additionally, the study design allowed us to investigate whether or not methylphenidate had any effect on breathing variables. Twenty-eight children (22 boys) aged 6–12 years meeting diagnostic criteria for Diagnostic and Statistical Manual of Mental Disorders (DSM)-IV ADHD were studied together with matched controls. Two nights of polysomnography (PSG) were conducted that included recordings of snoring waveforms. A randomly assigned 48-h on-off medication protocol was used for ADHD children. Control children’s recordings were matched for PSG night, but medication was not used. A low apnea-hypopnea index (AHI) threshold of >1event per hour was used to define sleep-disordered breathing (SDB) because of a clinical relevance in ADHD. Categorical analyses for paired binary data showed no significant differences between control and ADHD children for presence of an AHI >1 or snoring. Variables were extracted from a significantly shorter total sleep time (67 min) on the medication night in children with ADHD. Eight (28%) control and 11 (40%) ADHD children snored >60 dB some time during the night. Methylphenidate had no effect on central apneas, AHI, desaturation events, or any snoring data. Our PSG findings show no strong link between ADHD and SDB although our findings could be limited by a small sample size. Findings from PSG studies in the literature argue both for and against an association between ADHD and SDB. Our results suggest medication is not a factor in the debate.