Our research is focused on „nature and nurture“ in brain development, on developmental consequences of deafness, methods of its compensation by neuroprostheses and the adaptation of the brain to the neuroprosthetic stimulation. So far, the cochlear implant has been the clinically most successful neuroprosthetic device. We work on its further improvements and search for alternative ways of the stimulation of neurons in general, including stimulation within the central auditory system and the brain.

    As brain development depends on experience, the most devastating effects on the brain are observed when hearing loss sets in during childhood. We could show that in congenitally deaf animals feature sensitivity and representation of auditory space are degraded, indicating degraded disrcimination ability. Formation of auditory categories (“objects”), control of auditory plasticity (learning) and integration of sensory input into ongoing cortical activity are further compromised, partly due to the malfunction of auditory microcircuits. These deficits lead to the inability to compute errors between prediction about sensory input and actual sensory input and interfere with top-down interactions in the cortex. This prediction error drives learning in hearing-competent adult subjects. In congenital deafness, some of the auditory cortex is even recruited for non-auditory function (cross-modal reorganization). Congenital deafness consequently leads to widespread brain adaptations, including higher-level functions, as suggested by the connectome model of deafness. When hearing restoration takes place late in life, auditory learning capacity is reduced and deficits in representation of auditory input persist. We discovered the neural correlate of sensitive (critical) periods for cochlear implantation: the earlier in life cochlear implantation is performed, the faster and better is the adaptation of the primary auditory cortex to the implant and the more extensive is the compensation of the deficits induced by congenital deafness. We could uncover several neural mechanisms responsible for such sensitive periods.

    We described a reorganized brain representation of the ears following inborn single-sided deafness and were the first to demonstrate its neural correlates and a sensitive period for its therapy. It likely constitutes a clinical syndrome that we suggested to call aural preference syndrome. Data from implanted kids with single-sided deafness by many centers around the world support this suggestion.

    Outcomes of therapy of hearing are still characterized by large variability. Our goal is to built the scientific base for a comprehensive differential diagnosis and therapy of sensory loss tailored to the needs of the individual subject, by that eliminating this variability. Our research focuses on cochlear health and on the variability of the microanatomy of the human cochlea. Our research has recently provided a tool for virtual cochlear implantation with a given cochlear implant in the given (individual) patient cochlea. For the first time this allows to predict which electrode optimally fits the given subject‘s cochlea.