Swallowing reflex may be involved in cot death

A protective reflex that stops breathing when food “goes down the wrong way” may be involved in cot death, scientists have claimed.

Scientists believe poor coordination between two parts of the brain that work together to control breathing and swallowing might play a key role in Sudden Infant Death Syndrome (Sids). The reflex brings the vocal cords together to trigger coughing and swallowing.

In babies it is especially important because they have a tendency to regurgitate liquids after feeding.

But it is also risky, since when breathing stops blood oxygen levels can drop to dangerously low levels. Lead researcher Paul Pilowsky, professor from Macquarie University in Sydney, Australia, said: “The closing of the airway in adults is only a small compromise as breathing is only stopped temporarily.

“But for babies the response has more radical implications, particularly if breathing stops for a long time, as they can’t take in oxygen or get rid of carbon dioxide.

“The timing of breathing and swallowing is exquisitely coordinated. We suspect that coordination of the two may be going awry in Sids, but to be sure of this, we need to know how the brain organises this response in the first place.”

Working with rats, the scientists used electrical stimulation to mimic the brain and body’s response to a throat irritant.

By measuring neural activity linked to the reflex the team hopes to get a better understanding of what causes the brain to halt breathing for long periods. The research is published in the Journal of Physiology.

Prof. Pilowsky added: “The next step is to work out why these regions ‘decide’ whether breathing should be stopped. The eventual hope is to have the ability to manipulate these two systems separately to prevent the excessively long breathing arrest that may cause Sids.”