Studies of the Human Cochlea with Aspects on Future Hearing Rehabilitation

More than 600 million people suffer from neurosensory diseases, with hearing loss being one of the dominant causes of all ages. Deafness affects 2-3 children in 1000 born, over 10% of adults and 30% of elderly individuals above 65 years of age. Most patients with a hearing problem are diagnosed with sensorineural hearing loss primarily caused by hair cell dysfunction. Auditory neuropathies may be more frequent than earlier understood and studies of human ear may suggest additional filtering and synchronous activity in the first neuron important for speech coding. Cochlear implantation and prospects of treating inner ear disorders by application of substances into the middle ear necessitate further exploration of the human labyrinth. Still our knowledge of the structure/function of the human spiral ganglion (SGC) relative to electric stimulation is limited. In our study specimens were obtained at surgery for large life-threatening petro-clival meningioma after patient and ethical committee consent. Excellently preserved human tissue could be obtained after decalcification and observation in a TEM (JEOL 100 SX) and Field Emission Scanning Electron Microscope (ZEISS DSM 982 Gemini Field Emission Electron Microscope), and laser confocal microscopy (Nikon TE2000, DEclipse C1). The fine structure of the human cochlear nerve and hair cells could be analysed. This presentation is a short “round trip” in the human cochlea presenting some anatomical characteristics that may be useful to recognize during surgery and future inner ear research. New research in molecular medicine, gene therapy, stem cell inducement and nano-technology may lead to further breakthroughs in diagnostic, with new causative treatments of diseases of the auditory systems. We may anticipate a challenging future in regenerative medicine with new techniques to induce cell repair even in patients suffering from neural deafness. However, it is also imperative not to furnish unrealistic promises but give reasonable prospects for future progress. This presentation will focus on some results obtained recently in these fields and try to foresee strategies and advances for further progress of hearing rehabilitation.<BR><BR>All studies adhered to the rules of the local ethical committe and standards for animal care (Nr. 99398, 22/9 1999, C254/4, C45/7 2007) and patient consent. Research is a part of the European Community 6^th Framework Programme on Research, Technological Development and Demonstration (Nanotechnology-based targeted drug delivery; contract number: NMP-2004-3.4.1. 5-1-1; project acronym: NANOEAR). Supported in Sweden from Stiftelsen Tysta Skolan, Hörskadades Riksförbund (HRF) och Sellanders Stiftelse.