Sleep-disordered breathing in children is characterized by recurrent events of partial or complete upper airway obstruction during sleep, resulting in disruption of normal gas exchange (intermittent hypoxia and hypercapnia) and sleep fragmentation. The major symptom is snoring or noisy breathing. Sleep Disordered Breathing (SDB) is a wide spectrum of disorders that includes primary snoring, UARS and OSA. The main etiology for SDB in children is enlarged tonsils and adenoids and therefore the first line of treatment in pediatric SDB is adenotonsillectomy.

The objectives of this study are:

1. To investigate the natural history of primary snoring
2. To investigate the effect of seasonality on SDB severity
3. To compare the effect of adenoidectomy to adenotonsillectomy in the treatment of SDB in children
4. To characterize the children referred for repeated PSG following adenoidectomy or adenotonsillectomy and the indications for second PSG evaluation.

Inclusion Criteria:

• healthy normally developing children that underwent PSG evaluation at the Tel Aviv Medical center between 2005-2010

Exclusion Criteria:

• Chronic medical and neurodevelopmental conditions.
• Congenital anomalies.

Healthy children 0-18 years old that underwent PSG evaluation at the Pediatric Sleep Center at Dana Children's hospital between 2005-2010