Try this experiment: look at the landscape around you and cover one eye. Can you still judge the distance to the little group of trees, the shed or the field? It will be more difficult than when you use both eyes. It’s just the same when you use one rather than two ears, or one CI rather than two. With just one CI you won’t be able to tell whether the noise or the voice is coming from your right, from your left or from behind. Your sense of spatial hearing is lost. Distinguishing between noise and speech is difficult, and speech understanding in noise is reduced. This is why, as a rule, we recommend bilateral cochlear implantation if surgery is indicated for both ears.