Method and Apparatus for Fitting a Visual Prosthesis Using Electrically Evoked Responses

Patent metadata

Field	Value
Publication number	US-2019269316-A1
Application number	US-201916416047-A
Country	US
Kind code	A1
Filing date	May 17, 2019
Priority date	Dec 3, 2010
Publication date	Sep 5, 2019
Grant date	—

Abstract

The invention is a method of automatically adjusting a visual prosthesis electrode array to the neural characteristics of an individual patient. By recording electrically evoked responses to a predetermined input stimulus, one can alter that input stimulus to the needs of an individual patient. A minimum input stimulus is applied to a patient, followed by recording an electrically evoked response to the input stimulus. By gradually increasing stimulus levels, one can determine the minimum input that creates a neural response, thereby identifying the threshold stimulation level. One can further determine a maximum level by increasing stimulus until a predetermined maximum neural response is obtained.

First claim

What is claimed is:

1 . A method of fitting an implantable neural stimulator comprising:
a. providing an implantable neural stimulator including electrical components and an array of electrodes suitable to stimulate visual neurons; b. providing a computer, the computer completing steps c through 1 under automatic control of the computer; c. stimulating the visual neurons with a series of electrical stimulation signals through a selected subset of the array of electrodes; d. recording electrically evoked response levels of measured neural activity induced by the step of stimulating the visual neurons to produce response signals of the measured neural activity; e. filtering the response signals; f. applying a wavelet transform to the response signals to filter out any artifacts caused by the electrical components in the implantable neural stimulator; g. discarding the response signals with large artifacts; h. averaging epochs in the response signals; i. comparing each level of the response signals to each level of the stimulation signals; j. determining a relationship between the each level of the stimulation signals and each level of the response signals; k. repeating steps c-j for different selected subsets of the array of electrodes; l. determining and storing desired levels of stimulation based upon the comparison of the levels of the response signals and the levels of the stimulation signals; and m. stimulating the visual neurons with the implantable neural stimulator to induce the perception of vision based on the desired levels of stimulation signals.

2 . The method according to claim 1 , wherein the step of stimulating the visual neurons includes increasing the electrical charge of the electrical stimulation signals until the neural activity is detected.

3 . The method according to claim 1 , wherein said step of stimulating the visual neurons includes decreasing the electrical stimulation signals when a predetermined level of the neural activity is reached.

4 . The method according to claim 1 , further comprising analysis of the delay period between the step of stimulating the visual neurons and the measurement of the neural activity, wherein the delay period varies according to a level of input stimulus, and this variation is used in the fitting process.

5 . The method according to claim 1 , wherein storing a level of stimulation includes storing a threshold for each electrode in the array of electrodes.

6 . The method according to claim 1 , further comprising averaging multiple epochs of the neural activity.

7 . The method according to claim 1 , further comprising ignoring the neural activity greater than a predetermined voltage.

11 . The method according to claim 7 , wherein the predetermined voltage is between 40 μV and 60 μV.

Assignees

• Second Sight Medical Products Inc
• Univ Johns Hopkins

Inventors

• Greenberg Robert J
• Dagnelie Gislin
• Stronks Hendrik C

Classifications

• A61B3/0025 Primary

  characterised by electronic signal processing, e.g. eye models · CPC title

• A61N1/36046

  of the eye · CPC title

• A61B5/0496

  Human Necessities · mapped topic

• A61B5/398

  Electrooculography [EOG], e.g. detecting nystagmus; Electroretinography [ERG] · CPC title