gms | German Medical Science

56. Jahrestagung der Deutschen Gesellschaft für Neurochirurgie e. V. (DGNC)
3èmes journées françaises de Neurochirurgie (SFNC)

Deutsche Gesellschaft für Neurochirurgie e. V.
Société Française de Neurochirurgie

07. bis 11.05.2005, Strasbourg

Interfacing of central Neuroprostheses

Ankopplung zentraler Neuroprothesen

Meeting Abstract

Suche in Medline nach

  • corresponding author S. K. Rosahl - Abteilung Allgemeine Neurochirurgie, Albert-Ludwigs-Universität Freiburg
  • C. Pantazis - Abteilung Allgemeine Neurochirurgie, Albert-Ludwigs-Universität Freiburg
  • F. Gharabaghi - Abteilung Allgemeine Neurochirurgie, Albert-Ludwigs-Universität Freiburg

Deutsche Gesellschaft für Neurochirurgie. Société Française de Neurochirurgie. 56. Jahrestagung der Deutschen Gesellschaft für Neurochirurgie e.V. (DGNC), 3èmes journées françaises de Neurochirurgie (SFNC). Strasbourg, 07.-11.05.2005. Düsseldorf, Köln: German Medical Science; 2005. Doc11.05.-15.02

Die elektronische Version dieses Artikels ist vollständig und ist verfügbar unter: http://www.egms.de/de/meetings/dgnc2005/05dgnc0254.shtml

Veröffentlicht: 4. Mai 2005

© 2005 Rosahl et al.
Dieser Artikel ist ein Open Access-Artikel und steht unter den Creative Commons Lizenzbedingungen (http://creativecommons.org/licenses/by-nc-nd/3.0/deed.de). Er darf vervielf&aauml;ltigt, verbreitet und &oauml;ffentlich zug&aauml;nglich gemacht werden, vorausgesetzt dass Autor und Quelle genannt werden.


Gliederung

Text

Objective

Neuroprosthetics is a relatively new field on the border between clinical neurosurgery and neuroscience. Interdisciplinary challenges have to be addressed both by laboratory research and by surgeons in the operating room. While multiple implants have been designed to restore lost neural function (e.g. auditory brainstem implant, brain-machine-interface, visual implant) there are common issues for all these developments. One of these issues – the problem of implant interfacing with the CNS – has been tackled by this study with penetrating electrodes for brainstem implants.

Methods

(1) Anatomical variability at the site of stimulation The variability in orientation, size and shape of the cochlear nucleus was investigated in 25 human brainstem specimens with a precision of 4μm. On basis of these data, arrays of penetrating microelectrodes were designed to stimulate the primary auditory neurons in the ventral portion of the cochlear nucleus.

(2) Implant effectiveness The area of the cochlear nucleus was microsurgically exposed in 10 cats. Surface and penetrating electrodes were implanted at the site of stimulation and at the inferior colliculus. Impedance and electrically evoked auditory brainstem potentials were measured to assess the implant dynamics.

(3) Biocompatibility was investigated in histological studies after chronic implantation in the parietal cortex of 30 rats.

Results

There is considerable variability in the dimensions of the human cochlear nucleus. The surface depth of the human ventral cochlear nucleus (VCN) varied over the ventro-dorsal extension between 0.09 to 10,71mm. The maximum extension of the VCN was 5.2x2.2x3.2 mm; the dorsal cochlear nucleus was smaller and more flat (mean: 4.1x0.8x1.8 mm).

Due to lower threshold and lower saturation the dynamic of the penetrating and surface electrodes were almost identical (19.5±2.4 dB versus 18.3±3.4 dB, p=0.22). Morphological lesions after prolonged electrical stimulation (1.5 kHz) of penetrating electrodes occurred at 7.5nC charge/phase and a charge density of 164μC/cm2.

Conclusions

Anatomic variability at the site of implantation, functionality of surface versus penetrating electrodes, and biocompatibility are basic constraints that apply not only to auditory brainstem implants. Studies aimed at solving these questions provide valuable data for interfacing of other central neuroprosthesis and may propel synergistic research in this interdisciplinary field.