"Mild OSA" is an evolving definition; it is characterized by the polysomnographic finding of AHI range greater than 1 and less than 5, defined by Katz and Marcus.(Wagner 2007) This range corresponds to the difference in the defined pathological minimum AHI for children (normal AHI < 1) and adults (normal AHI < 5). In practice, "mild OSA" remains a common reason for delaying adenotonsillectomy in an otherwise asymptomatic child, since children with mild OSA have been shown to exhibit neurocognitive functioning equivalent to controls.(Calhoun 2009) However, psychosocially these children often have problems, and adenotonsillectomy has been shown to improve these children's behavior as measured by atypicality, depression, hyperactivity, and somatization.(Mitchell 2007) Furthermore, among one-third of children with mild OSA, the natural history is progression of disease.(Li 2010)