For quite some time, the literature on childhood sleep apnea has shown that sleep apnea leads to cognitive and behavioral issues.
Startlingly, repeated studies have found that a large portion of children who are diagnosed with ADHD have sleep apnea and that treating this sleep apnea helps to treat the symptoms of ADHD. I know of a study in the US and one in Taiwan that both showed the majority of a sample of ADHD-diagnosed children had sleep apnea. The Taiwan study performed adenotonsillectomy on some of these children and showed that it had positive behavioral improvements beyond those in a ritalin-treated control group.
Why aren’t children, and adults for that matter, before diagnosis with ADHD first given a proper polysomnography? I’m convinced that it is because sleep apnea is a disease that is not only poorly understood by lay people, but that even doctors who focus on sleep medicine don’t understand the true prevalence of sleep apnea in children and young adults, especially those who are not obese.
Why don’t doctors recognize the high prevalence even though it is documented in population studies? One reason, I think is because young people might not respond as well to PAP therapy as older sleep apnea patients, and many doctors see response to PAP therapy as the real signal that sleep apnea is present (ignoring PSGs, respiratory effort related arousals). The American Academy of Sleep Medicine has recently said that half of their accredited clinics are not using arousal based scoring of PSGs, which will leave a lot of children and young adults (and older adults for that matter) undiagnosed and improperly treated (as proper PAP titration requires a properly read PSG).
How many IQ points are lost to sleep apnea, and how much ADHD could be prevented through early recognition and treatment of sleep apnea? It seems like quite a lot and something that society should be investing in.