Hybrid fitting for a visual prosthesis

Patent metadata

Field	Value
Publication number	US-9889301-B2
Application number	US-201615195646-A
Country	US
Kind code	B2
Filing date	Jun 28, 2016
Priority date	Oct 3, 2011
Publication date	Feb 13, 2018
Grant date	Feb 13, 2018

Abstract

The present invention is an improved fitting and training system for a visual prosthesis. Fitting a visual prosthesis through automated means is challenging and fitting a visual prosthesis manually is tedious for clinician and patent, and provides great opportunity for error. A hybrid of computer controlled and manual fitting provides effective, efficient and controlled fitting process. The process includes testing a group of electrodes in random order by providing a prompt followed by stimulation and the patient responding if they saw a percept. After each set, a maximum likelihood algorithm is used to determine the next stimulation level, or if further stimulation is needed for each electrode.

First claim

The invention claimed is:

1. A method of brightness fitting for a visual prosthesis comprising:
a. providing an external video processor and an implantable visual neural stimulator including an array of electrodes suitable to contact visual neural tissue;
b. testing the implantable visual neural stimulator to verify function and matching to the external video processor;
c. activating a prompt;
d. activating signals at varying levels on a selected electrode within a subset of electrodes in the array of electrodes;
e. receiving a response from a subject indicating a visual perception;
f. recording the level that elicited the response indicating the visual perception;
g. repeating the steps c through f for each electrode in the subset;
h. determining if a predetermined minimum number of electrodes in the subset elicited responses indicating visual perceptions;
i. if the predetermined minimum number of electrodes did not elicit responses indicating the visual perceptions, activating the subset of electrodes in the array of electrodes simultaneously as a group at varying levels;
j. receiving a subset response from a subject indicating a subset visual perception; and
k. recording the level that elicited the subset response indicating the subset visual perception from stimulating the subset of electrodes.

2. The method according to claim 1 , wherein the subset of electrodes includes four electrodes.

3. The method according to claim 1 , wherein the step of activating a signal includes activating no signal at a pseudorandom interval.

4. The method according to claim 1 , further comprising generating a video configuration file from results of the steps of recording responses indicating visual perception.

5. The method according to claim 1 , further comprising after each response applying a predetermined computer algorithm to determine a next activation level for each selected electrode.

6. The method according to claim 5 , wherein the predetermined algorithm predicts a confidence of a correct answer based upon a consistency of previous answers.

7. The method according to claim 5 , wherein the predetermined algorithm is a maximum likelihood algorithm.

8. The method according to claim 6 , wherein the predetermined algorithm is according to the equation

L
i

=

∏

q
=
1

m

⁢

⁢

(

p

q
,
i

)

n

yes
,
q

·

(

1
-

p

q
,
i

)

n

no
,
q

Where:
L i is the likelihood that the threshold value is at level i
P q,i is the probability, according to the Psychometric Function, that the patient will perceive a stimulation at level q given that the threshold is at level i
n yes, q is the number of Yes responses in all previous presentations (trials) at level q
n no, q is the number of No responses in all previous presentations (trials) at level q
m is the number of levels in the range-the highest level.

Assignees

• Second Sight Medical Products Inc

Inventors

• Dorn Jessy D
• Roy Arup
• Greenberg Robert J
• Caspi Avraham I

Classifications

• A61N1/36046 Primary

  of the eye · CPC title

• A61N1/37252

  Details of algorithms or data aspects of communication system, e.g. handshaking, transmitting specific data or segmenting data · CPC title

• A61N1/37241

  providing test stimulations · CPC title

• A61N1/0543

  Retinal electrodes · CPC title

• A61N1/37247

  User interfaces, e.g. input or presentation means · CPC title