NEW YORK (Reuters Health) Mar 24 - Infants with snoring-related respiratory arousal have lower scores on standardized mental development assessments, the results of a study published in the March issue of Pediatrics suggest. Exposure to secondhand cigarette smoke may contribute to the deleterious effects of infant snoring.

"The link between sleep-disordered breathing and neurocognitive functioning in preschool and school-aged children now has been established clearly," Drs. Hawley E. Montgomery-Downs, of West Virginia University, Morgantown, and David Gozal of the University of Louisville in Kentucky point out.

In their study, the researchers assessed the potential association between snoring and decrements in developmental performance among 35 healthy infants. The possible contribution of exposure to cigarette smoke was also examined. The infants (mean age 8.2 months) underwent full overnight polysomnography recordings, and were administered the Bayley Scales of Infant Development, including the Mental Developmental Index.

Respiratory arousal index was significantly negatively correlated with Mental Development Index and snoring-associated arousals accounted exclusively for this association. No significant correlation was found between Mental Development Index score and spontaneous arousals, arousals associated with episodes of central apnea or oxyhemoglobin desaturation. All infants had an apnea-hypopnea index of 0.

Thirty-three percent of the infants were from a home in which at least one parent smoked. Infants from smoking households were more likely to snore and significantly more likely to have respiratory-related arousals. However, no significant differences on Mental Development Index scores were seen between infants from smoking or non-smoking households.

"This study and others clearly support the need for identification and evaluation of the youngest children with recognizable risk factors for sleep disordered breathing," the authors conclude. "This may pose a formidable challenge when we consider that the symptoms of sleep disordered breathing, such as snoring, are less frequently the presenting complaint in such children when compared with associated comorbidities, such as recurrent upper respiratory tract infections and delays in growth and development."