Polysomnographic assessment of 20 adolescents who were referred to hospital for loud and frequent snoring showed they suffered from obstructive sleep apnea syndrome (OSAS). Their apneas and desaturation rates (SaO2) were abnormal in comparison with the non-snoring adolescents, who served as their controls. The snoring group obtained lower scores on phonemic and semantic tests and had lower marks in the Greek language subject at school than the non-snoring group. These findings could be explained by the fact that OSAS causes certain physiological disturbances which may lead to dysfunction of the prefrontal cortex which plays an active role in language and verbal skills.