STIMULATION METHOD FOR MAINTAINING THE RESPONSIVENESS OF ELECTRICALLY EXCITABLE CELLS TO REPEATED ELECTRICAL STIMULATION

• US 20130310899A1
• Filed: 01/24/2012
• Published: 11/21/2013
• Est. Priority Date: 01/24/2011
• Status: Active Grant

• Current Assignee: NewSouth Innovations Pty Limited (University Of New South Wales)
• Original Assignee: NewSouth Innovations Pty Limited (University Of New South Wales)
• Inventors: Lovell, Nigel Hamilton, Tsai, David, Morley, John William, Suaning, Gregg Jorgen
• Granted Patent: US 9,669,213 B2
• Time in Patent Office: Days
• US Class Current: 607/62
• CPC Class Codes: A61N 1/0543 Retinal electrodes
• CPC Class Codes: A61N 1/36046 of the eye

Abstract

A method of neural stimulation is described for maintaining the responsiveness of electrically excitable cells to repeated electrical stimulation. A stimulating signal (23) is applied to the electrically excitable cells. The stimulating signal is repeatedly applied (26, 29, 32, 35) with a progressively increasing signal strength. A quiescent period (44) may be interleaved between bursts (43, 45) of stimulation. The electrically excitable cells may be retinal cells.

Claims

1-20. -20. (canceled)

21. A method of neural stimulation comprising:

applying a stimulating signal to electrically excitable cells; and

repeating the application of the stimulating signal with a progressively increasing signal strength by increasing a total electric charge applied to the cells per application to maintain responsiveness of the cells to the repeated stimulating signal.

22. The method according to claim 21 wherein increasing the signal strength comprises increasing an amplitude of the stimulating signal.

23. The method according to claim 21 wherein increasing the signal strength comprises increasing a pulse duration of the stimulating signal.

24. The method according to claim 21 wherein increasing the signal strength comprises increasing a number of pulses applied within a specified time period.

25. The method according to claim 21, further comprising:

interleaving repeated applications of the progressively increasing stimulating signal with a quiescent period.

26. The method according to claim 25 wherein the signal strength is reset to an initial value following the quiescent period.

27. The method according to claim 21 wherein the stimulating signal comprises a biphasic pulse having two phases of opposite charge.

28. The method according to claim 27 wherein increasing the signal strength comprises increasing an electric charge of each of the two phases.

29. The method according to claim 27 wherein the two phases of the biphasic pulse are separated by an inter-phase delay.

30. The method according to claim 27 wherein an anodic phase of the biphasic pulse contains a substantially equal and opposite charge to a cathodic phase of the biphasic pulse.

31. The method according to claim 21 wherein one or more parameters define a progression of the progressively increasing signal strength, the method comprising:

calibrating the one or more parameters to maintain the responsiveness of the electrically excitable cells to repeated stimulation.

32. The method according to claim 31 wherein said calibrating comprises:

initialising the one or more parameters;

repeatedly applying the stimulating signal using the one or more parameters;

measuring a response of the cells to the repeated stimulation; and

adjusting the one or more parameters if the response of the cells varies with repeated stimulation.

33. The method according to claim 31 wherein said calibrating comprises:

initialising the one or more parameters;

repeatedly applying the stimulating signal to the cells of a human subject using the one or more parameters;

eliciting an assessment of an evoked response from the human subject; and

adjusting the one or more parameters if the elicited assessment indicates a variation in response of the cells with repeated stimulation.

34. A neural stimulator comprising:

a sensory detection device that in use detects sensory information;

an electrode array that in use is configured to stimulate electrically excitable cells; and

a processing circuit in data communication with the sensory detection device and the electrode array, wherein the processing circuit is configured to cause the electrode array to apply a stimulating signal to the electrically excitable cells dependent on the detected sensory information and to repeat the application of the stimulating signal with a progressively increasing signal strength by increasing a total electric charge applied to the cells per application to maintain responsiveness of the cells to the repeated stimulating signal.

35. The neural stimulator according to claim 34 wherein the processing circuit is further configured to interleave a quiescent period between a first burst of repeated applications of the stimulating signal and a second burst of repeated applications of the stimulating signal.

36. The neural stimulator according to claim 35 wherein the first burst comprises between 2 and 20 applications of the stimulating signal with the progressively increasing signal strength.

37. The neural stimulator according to claim 36 wherein a total duration of the first burst is greater than 2.2 ms.

38. The neural stimulator according to claim 35 wherein a duration of the quiescent period is greater than 50 ms.

39. The neural stimulator according to claim 34 wherein the electrically excitable cells are retinal cells and wherein the sensory detection device is an image processing device.

40. The neural stimulator according to claim 34 wherein the sensory information includes sensory information external to the cells.