Response to letter to the editor: comment on usher's syndrome: evaluation of the vestibular system with cervical and ocular vestibular evoked myogenic potentials and the video head impulse test

In our clinical study, a vestibular protocol to evaluate patients affected by Usher’s syndrome was designed to investigate their otolith and ampullary functions. All patients were selected by the ophthalmologists who adopted various parameters (severity of hearing loss, the presence of vertigo, the severity and the age of visual loss onset). The main purpose of our study was to evaluate the presence of ‘‘latent’’ vestibular damage in patients clinically classified as USH2, who theoretically should not have any damage to the vestibular receptors. Although we were aware of the importance of the genetic screening technique, as claimed in the ‘‘Discussion’’ section (1), genetic studies to analyze the type of genetic mutation present for better characterizing USH I or USH II patients were not performed. Genetic analysis of allelic mutation related to the Usher syndrome type and subclass (MYO7A, CDH23, PCDH15, USH1C, USH1G, USH2A, ADGRV1/GPR98, DFNB31, CLRN1, PDZD7) is actually under way for all patients enrolled in the study (2,3). These genetic results will be compared with the vestibular tests to clarify whether the clinical classification adopted confirms the results of the study.