The vestibular system is part of themultisensory balance sense, which is responsible for postural control, gaze stabilization, and spatial orientation. In particular, the vestibulo-ocular reflex (VOR) is responsible for generating compensatory eyemovements relative to headmovements while moving. In patients with a bilateral loss of vestibular function, the VOR is absent or very weak. As a consequence, such patients complain about oscillopsia, the illusory perception of movement of the visual surroundings in dynamic situations. The direct functional consequence of this is an abnormal decrease of visual acuity when in movement (Lambert et al., 2010; Guinand et al., 2012), which translates into difficulty in reading signs and recognizing faces while walking. This considerably contributes to a significant impairment of the quality of life of affected patients. Currently, there is no evidence of an effective treatment for these patients. The idea of electrically stimulating the vestibular system emerged about a decade ago and is based on a concept very similar to that of cochlear implants. Briefly, such a system would use inertial sensors (i.e. a gyroscope and/or accelerometer) to detect motion information. Such information is translated into a pattern of neural excitation code by an external signal processor. This pattern is wirelessly transmitted to an implanted stimulator which finally delivers the corresponding patterns of electrical stimulation via electrodes implanted near the vestibular structures in the neural system. The translation of the cochlear implant concept into a device suitable for stimulating the vestibular system requires two steps: (1) adaptation of the electrode topology to the neural target to be stimulated, and (2) transformation of the pertinent input signal (in this case motion) into a signal that can be processed by the audio processor of a standard cochlear implant. Today, both steps have been completed. A modified cochlear implant providing 1–3 extracochlear electrodes was developed in collaboration with MED-EL (Innsbruck, Austria). Our research group has developed the necessary interfaces to capture the signal coming from a gyroscope and use it to modulate the stimulation signals delivered by the cochlear implant stimulator (Geneva University Hospitals: Device and method for electrical stimulation of neural or muscular tissue; 2013-01-30; European Patent Application 13153300.2-1652). A number of studies have contributed to establish the feasibility of the idea of restoring semicircular canal function via electrical stimulation in animal models. At the same time, several important steps have been taken towards the development of a system allowing for the chronic stimulation of the vestibular system in human patients. For example, special extralabyrinthine (Kos et al., 2006) and intralabyrinthine (Van de Berg et al., 2012) surgical techniques have been developed and the feasibility of electrical stimulation of vestibular structures has been demonstrated both in acute (Guyot et al., 2011a) and chronic configurations (Guyot et al., 2011b). To date, seven volunteer patients with a profound bilateral vestibular loss have received a custom-modified cochlear implant in which one or three electrodes are in contact with the vestibular structures (see Table 1). In addition, since hearing loss due to the implantation of electrodes near the vestibular system remains an important concern, patients were also profoundly deaf in the implanted ear. Two patients (BVL1 and BVL2) were implanted using the intralabyrinthine approach (Van de Berg et al., 2012) in Maastricht (Ethics committee protocol NL36777.068.11/METC 11-2-031). Five patients (BVL3–BVL7) were implanted using the extralabyrinthine approach (Kos et al., 2006) in Geneva (Ethics Committee protocol NAC 11-080). Correspondence to: Marco Pelizzone, Department of Otorhinolaryngology, Head and Neck Surgery, Geneva University Hospital, Geneva, Switzerland. Email: marco.pelizzone@hcuge.ch