The aim of this work package is to understand outcome variations in individuals with hearing impairment following therapy, where a number of treated children do not meet the expectations of the clinicians. The reasons for this variability are unknown. Along with peripheral factors (e.g. individual size of the cochlea, binaural vs. monaural hearing) also central factors play a cardinal role. The extent and limits of brain plasticity in children and the available brain resources will directly influence the outcome of auditory restoration and are a likely factor of variability. One particular focus will be the role of hearing and the consequences of hearing impairment for mutual integration of sensory inputs and the cognitive adaptations, as well as the relationship between individual variations and outcome variability.