"Minimized rotational vestibular testing" as a screening procedure detecting vestibular areflexy in deaf children: screening cochlear implant candidates for Usher syndrome type I.

Morbus Usher (USH), a combination of sensorineural hearing loss and retinal visual impairment, is classified into group I-III. USH I patients are born deaf. Within the first 10 years of life, they develop a severe vision impairment due to progressive retinal dystrophy (retinitis pigmentosa). USH I patients show vestibular deficits. The incidence of USH I among congenitally deaf children is assumed to be as high as 10%. We intend to create a simple examination procedure for screening congenitally deaf children for vestibular deficiency and subsequently USH I. The examination procedure is named "Minimized Rotation". The vestibular function of deaf children was examined by Minimized Rotation during their preoperative cochlear implant candidacy examination. A lack of postrotational nystagmus was seen as an indication for vestibular deficit. Subsequently some of these patients were examined under general anaesthesia by electroretinography (ERG) at the Department of Ophthalmology. A total of 117 children were examined by Minimized Rotation. In 19 children (16.2%) no rotational nystagmus was found. Six of these children were additionally examined at the Department of Ophthalmology using Ganzfeld ERG. Three of them (50%) showed generalized dysfunction of the retina; 8.1% of the children undergoing preoperative evaluation for cochlear implatation are assumed to show abnormalities of the retina. Rotational examination seems to be an appropriate screening method to detect vestibular deficits, which is one sign of USH I. The results always have to be verified by Ganzfeld-ERG or further genetic investigations. Children with USH I are threatened by progressive reduction of vision. We, therefore, consider USH I children always to be implanted bilaterally with a cochlear implant to maximize the benefit of auditory rehabilitation.