optic nerve prosthesis

1. ResearchTalks
Université catholique de Louvain
Neural stimulation, challenges and success
Stimulation neurale, succès et défis
Jean DELBEKE, MD, PhD
10/10/2011
Louvain-la-Neuve

2. From Prometheus to Cyborg fiction
• The pacemaker has opened
the gate towards functional
electrical stimulation.
• Cochlear prosthesis, sphincter
control, drop foot system, pain
stimulators, vagus nerve
stimulation, the visual
prosthesis and many others
including deep brain stimulation

4. Apprentissage de la reconnaissance de patterns
100
80
Score (%)
60
40
20
0
1 2 3 4 5 6 7 8 9 10
Evaluation
57 s

5. Virtual perception experiment
Frequency (Hz) 9 p
mA 0 100 200 300 400
-0,5
9 p; 106.5 µs
-0,4 F Model
100 µs pulse trains
-0,3 80 Hz;106.5 µs
N Model
-0,2
-0,1
0,0
0 10 20 30 40
Number of pulses (N) 80 Hz

6. Rhéobase for the perception of pulse trains
µA
1998 2008
N F F (Hz)
1 10
2 20
4 40
8 80
16 N 160
32 320

7. Wrong assumptions are still the rule
And yet results
are being obtained
The visual prosthesis

8. Moi, personne consciente,
libre de penser, vouloir et créer

9. Phosphene position
90° 180°
Optic nerve
0° 270°
Axons:
0.6 µm
0.9 µm
1.2 µm
Visual field

10. Empedocles (490-430 BC) put forward the
idea that we see objects because light
streams out of our eyes and touches them.
(Wikipedia)
Control
CNS of eye
movements
Extraocular
muscles
Efference Copy
Motor Command
Extraocular proprioception
Retinal signal
Eye
Visual
localization Optic nerve
Comparator

11. Perception threshold of optic nerve stimuli
at different phases of the hearth beat
350.00 Threshold (µA)
300.00
250.00
200.00
150.00
0°
90°
100.00
180°
50.00 270°
% ECG cycle
0.00
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95

12. Sensors
Microfluidics NEUROPROBES

13. Biofilm Cell migration Growth Differentiation Matrix secretion
seconds minutes hours days weeks
Platelets,
Implant Protein
Monocytes Neovascularisation
Adsorption
Granulocytes
Gold, Co, Cr, Ni NO, VEGF
silver Fibrin clotting
erythrocytes
Complement Acute inflammation
Toxicity pathway Bacteria
TNFα, Fibroblasts,
Infection, TGFβ Macrophages
biofouling
Allergy, Large particles, Wound healing, scar
Prosthesis integration
anaphylaxis Granuloma frustrated
phagocytosis Fibrous capsule

14. DEEP (Drug-releasing Electrode with Enhanced Properties)
x+ 0
+x e-
A- + x A-
x
N -x e- N n
n
H H
PPy oxidized form PPy neutral (reduced) form
Conducting form Insulating form
Stores anions Releases anions

15. Typical model in bioengineering
When the other discipline is supposed to know why
project
Or about the importance to convey the unknown
Limited knowledge
Users need Design & Fabrication
Empiricism
Basic research Applied research
Economy
Available device Certifiable product

16. Neurotech ADNS-300
Nerve
-
Amp
Stimulation
+

17. Contributors to the optic nerve prosthesis
• Nos volontaires anonymes
• Université catholique de Louvain, Louvain-la-Neuve, Belgique
– Laboratoire de Microélectronique (DICE)
– Génie de la réhabilitation neurale (GREN)
– Clinique Universitaires St Luc
• Service d’ophtalmologie, de neurochirurgie, d ’ORL
– Commission d ’Ethique Hospitalo-Facultaire
• Matra Electronique, La Croix Saint Ouen, France
• NeuroTech S.A., Louvain-la-Neuve, Belgium
• CEA Leti, Grenoble, France
• ANCL, Case Western Reserve University, Cleveland, Ohio, USA
• Centro Nacional de Microelectronica, Barcelona, Spain
• Centre Suisse d’Electronique et de Microtechnique, Neuchâtel, Swisse
• Empirica GmbH, Bonn, Allemagne
• Norton-Desmarquest S.A., Saint-Gobin, Vincennes, France
• BiomeTech S.A., Lyon, France
• Service d ’Ophtalmologie de l ’Université de Gand, Belgique
• La Commission Européenne (Projets MIVIP et OPTIVIP), la région Wallonne de
Belgique, la fondation Alexandre VISION, le Lions club et un donateur anonyme

18. And later projects …
• Ecole Polytechnique de Louvain
– PCPM
– POLY
– ICTM
• Faculté de Médecine/MOEX
• UCLondon
• UGent
• UBath
• CNRS Lille
• AML
• It4ip