Restoring balance : replacing the vestibular sense with wearable vibrotactile feedback

Bilateral vestibular loss (BVL) is a disorder of the balance sensory organs in the inner ear; it can cause falls which may have grave consequences, particularly among elderly. This chapter presents the iterative user-centered design of a vibrotactile feedback mechanism for substituting the balance sense. Six wearable prototypes were created to compare the suitability of different body parts (foot, ankle, knee, waist, shoulder, upper arm) for perceiving this type of feedback and to compare different encoding mechanisms (number, intensity, and rhythm of vibrations). In a second iteration, two of these wearable devices (for the ankle and the waist), in two feedback encoding mechanisms (directional and non-directional) were improved and evaluated. Based on the combined studies and interviews conducted with patients and specialists, it is argued that vibrotactile non-directional balance feedback should be applied to ankles, and that such devices should be integrated in training systems.