Sample-specific current spread by means of NMR Imaging of the human cochlea

Magnetic Resonance Imaging (MRI) has allowed researchers to explore anatomical and functional features (e.g. fMRI, DTI) of the human body in 3D.

However little has been derived for current spread in models of the inner ear. Using MRI, sample specific 3D current spread may be explored. Existing Hodgkin-Huxley type models of the inner ear mostly implement 2D topologies of neurons and electrodes. These models take into account the current spread and its attenuation, but do not consider effects of the spiral-like shape of the cochlea. Current spread may be affected by the modiolus, a center-like structure, since the electrodes in cochlear implants are facing towards it.

We scan inner ears from different samples to build up subject-specific datasets. The MR images are used to extract cochlear features by using Blender - an open source CAD software. The gained datasets add geometrical information to the computational models for current spread in the cochlea. These models then compute the corresponding neuronal activity. Therefore we can achieve 3D computation of the current spread in models adapted to sample-specific geometries and thus gain insight into more realistic representations of the current spread inside the cochlea and the resulting neuronal activity.

3D anatomical MR images might provide valuable insights into understanding the excitation spread in different cochlear topologies. This may lead to individualized coding strategies for cochlear implants in the future, with further investigations needed.