Hybrid fitting for a visual prosthesis

Patent metadata

Field	Value
Publication number	US-9403006-B2
Application number	US-201514752507-A
Country	US
Kind code	B2
Filing date	Jun 26, 2015
Priority date	Oct 3, 2011
Publication date	Aug 2, 2016
Grant date	Aug 2, 2016

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 a visual prosthesis comprising:
a. providing an array of electrodes suitable to contact visual neural tissue;
b. activating a prompt;
c. activating a signal at a level on a selected electrode within a subset of the array of electrodes;
d. receiving a yes response from a subject indicating a visual perception at a threshold brightness level or a no response from the subject indicating no visual perception;
e. recording the yes or no response;
f. applying a predetermined computer algorithm which predicts a confidence of a correct answer based upon consistency of previous answers to determine a next activation level on the selected electrode; and
g. repeating steps b through f until the electrode is fit; and
h. repeating the steps b through g for each electrode in the subset.

2. The method according to claim 1 , wherein the signal is a signal on an individual electrode.

3. The method according to claim 1 , wherein the signal is a signal on a plurality of electrodes.

4. The method according to claim 3 , wherein the plurality is four.

5. The method according to claim 1 , wherein the prompt is an audio prompt.

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

7. The method according to claim 1 , wherein the predetermined algorithm is a maximum likelihood algorithm.

8. The method according to claim 7 , wherein the maximum likelihood 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.

9. A method of fitting a visual prosthesis comprising:
a. providing an array of electrodes suitable to contact visual neural tissue;
b. activating a prompt;
c. activating a signal on an electrode within a subset of the array of electrodes;
d. receiving a response from a subject indicating a visual perception;
e. recording the response;
f. repeating steps b through e for each electrode in the subset;
g. interpolating responses on electrodes not in the subset; and
h. applying a predetermined algorithm which predicts a confidence of a correct answer based upon consistency of previous answers to determine a next activation signal.

10. The method according to claim 9 , wherein the prompt is an audio prompt.

11. The method according to claim 9 , wherein the step of activating a signal includes activating no signal at a pseudorandom interval.

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