Hybrid Fitting for a Visual Prosthesis

Patent metadata

Field	Value
Publication number	US-2016303373-A1
Application number	US-201615195646-A
Country	US
Kind code	A1
Filing date	Jun 28, 2016
Priority date	Oct 3, 2011
Publication date	Oct 20, 2016
Grant date	—

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

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 implanted visual neural stimulator to verify function and matching to the external video processor; c. activating a prompt; d. activating a signal at a level on a selected electrode within a subset of the array of electrodes; e. receiving a response from a subject indicating a visual perception; f. recording the response; g. repeating the steps b through e for each electrode in the subset; h. determining if a predetermined minimum of electrodes in the subset elicited responses; and i. repeating steps b through e on simultaneous groups of electrodes if the predetermined minimum of electrodes did not elicit a response.

2 . The method according to claim 1 , wherein the simultaneous groups of electrodes include 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 , wherein the predetermined algorithm predicts a confidence of a correct answer based upon a consistency of previous answers.

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

6 . The method according to claim 4 , 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

7 . The method according to claim 13 , further comprising generating a video configuration file from results of the predetermined algorithm.

8 . 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.

Assignees

• Second Sight Medical Products Inc

Inventors

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

Classifications

• A61N1/0543

  Retinal electrodes · CPC title

• A61N1/36046 Primary

  of the eye · CPC title

• A61N1/37241

  providing test stimulations · CPC title

• A61N1/37252

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

• A61N1/37247

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