At 2 to 4 weeks of age, 2 to 3 months, and 5 to 6 months. The study also identified a dose-dependent relationship between cortical activation rates and levels of infant urinary cotinine, a nicotine metabolite.

The results sho that infants who had been exposed to smoke had reduced sub-cortical activation to cortical arousal. The infants' arousal responses during daytime sleep were compared with those of 13 healthy infants of nonsmoking mothers. They found that when mothers smoke, the sleep arousal process of infants, which awakens them in response to a life-threatening situation, is altered, increasing the risk for SIDS. They also had lower rates of full cortical arousals from sleep and higher rates of sub-cortical activations than infants of nonsmoking mothers.

Infants with the highest levels of smoke exposure had the lowest levels of cortical arousal.

-- Smoking by mothers has replaced infants sleeping on their stomachs as the greatest modifiable risk factor for sudden infant death syndrome, or SIDS, Australian researchers suggest. All the children were assessed three times. The study included 12 healthy, full-term infants born to mothers who smoked an average of 15 cigarettes a day.

Decreased cortical arousals from.