Genotype-phenotype Correlation Study of Presymptomatic and Symptomatic DFNA9 Patients

Systematic review of the genotype-phenotype correlation studies in P51S carriers has shown an underrepresentation of presymptomatic affected subjects and the calculation of vestibular deterioration were based on just one vestibular parameter, whereas the combined evaluation of a complete vestibular test battery, covering the complete vestibular sensitivity range and all labyrinthine compartments separately, is nowadays considered standard practice in determining more accurate assessment of the vestibular function. For this reason, a prospective cross-sectional study on pre- as well as symptomatic DFNA9 patients carrying the Pro51Ser (P51S) mutation in COCH gene is being carried out, in order to gain more realistic data on vestibular dysfunction, consisting of pure tone audiometry and a comprehensive vestibular test battery, including electro- or videonystagmography (VNG), C- and O-Vestibular-evoked myogenic potential (VEMP) tests, video Head Impulse Test (vHIT) and questionnaires (DHI (Dizziness handicap Index), oscillopsia questionnaire (OS), Quality of Life Questionnaire (EQ-5D-5L), activities-specific balance confidence (ABC) scale.