Head movements are measured by means of the peripheral vestibular system. The vestibular information is centrally processed to induce compensatory eye movements in order to ensure gaze stabilization. This reflex is called the vestibulo-ocular reflex (VOR). The VOR works optimally for natural head movements, which are in the case of man, fast movements (1-4 Hz). In clinical settings, the VOR in the dizzy patient is typically investigated at low stimulation frequencies (0.05 HZ). The main goal of the project is to evaluate the function of the VOR at high stimulation frequencies, being more physiological. The VOR will be analyzed in three dimensions (horizontal, vertical and torsional) in patients with specific vestibular lesions, such as acoustic neuroma and in patients with autosomal dominant hearing impairment.