The study, conducted by Ridha Joober, MD, and Reut Gruber, PhD, of Douglas Mental Health University Institute and McGill University in Montreal, Canada, focused on 37 children between six and 12 years old with ADHD that was diagnosed based on criteria from the Diagnostic and Statistical Manual - 4th Edition.
The subjects were divided into two groups based on the mean sleep efficiency score during the week of the placebo. Those above and below the mean were placed in the Poor Sleep Group and Good Sleep Group, respectively.
"Children with low sleep efficiency might improve performance following the administration of MPH as it increases their arousal level to a moderate level, which is presumed to facilitate vigilance performance," wrote Joober and Gruber. "To our knowledge, this is the first study in which the MPH response in children with ADHD has compared poor and good sleepers using an objective neuropsychological test and a validated clinical scale as the outcome measures.
Future studies looking at the association between the impact of MPH, basal characteristics of sleep and the efficiency of different attentional systems in children with ADHD are needed to further examine the association between sleep and neurobehavioral functioning in ADHD."
The CPT is a standardized computer-administered test in which single letters are presented on a computer screen at two different rates: once per second, once every two seconds or once every four seconds. Over the course of the test, the participant is asked to press a button in response to every signal except the target signal.
The utilized CPT measures included the total number of omissions (missed targets), total number of commissions (false hits), reaction time, reaction time variability, reaction time standard error, risk taking and signal detectability.
Sleep problems, particularly difficulties in initiating and maintaining sleep, are common in children diagnosed with ADHD. ADHD is most commonly treated with stimulant medications, such as MPH.
Parents who suspect that their child might be suffering from a sleep disorder are encouraged to consult with their child's pediatrician or a sleep specialist.