Intellectual disability (ID) is defined as “ condition characterized by significant limitations in intellectual functioning and adaptive behaviour, originating during the developmental period” The ID population has a higher prevalence of ear and hearing problems compared to the general population, but existing literature is limited to national studies or subgroups of the highly heterogeneous ID population. Furthermore, practically no information is available on the occurrence of vestibular problems. Auditory and vestibular dysfunctions may have a negative impact on social and communicative development, gross motor development and postural control, which are already compromised by the cognitive impairment in persons with ID. This warrants the need for reliable documentation of the occurrence and impact of auditory and/or vestibular deficits in the ID population. Special Olympics (SO), an international sports organization for people with ID, has implemented a Healthy Hearing (HH) screening programme during worldwide SO events since 1999. This resulted in a database of more than 85000 athletes that has never been analyzed. The first purpose of this project is to estimate the global prevalence of auditory dysfunctions in athletes with ID by retrospectively analyzing this database. Additionally, the occurrence of auditory and vestibular dysfunctions and their impact on the postural control and stability will be characterized in a controlled Belgian population with ID.