van AaremAHuygenPLMPinckersAJBleeker-WagemakersEMKimberlingWJCremersCWRJ. Stable and progressive hearing loss in type 2A Usher's syndrome. Ann Otol Rhinol Laryngol1996;105:962–7.
2.
WagenaarMvan AaremAHuygenPPieke-DahlSKimberlingWCremersC. Hearing impairment related to age in Usher syndrome types 1B and 2A. Arch Otolaryngol Head Neck Surg1999;125:441–5.
3.
PenningsRJEHuygenPLMWestonMD. Pure tone hearing thresholds and speech recognition scores in Dutch patients carrying mutations in the USH2A gene. Otol Neurotol2003;24:58–63.
4.
International Organization for Standardization. ISO 7029: Acoustics: Threshold by Air Conduction as a Function of Age and Sex for Otologically Normal Persons. Geneva, Switzerland: International Organization for Standardization, 1984.