System and method for measuring and fitting spatio-temporal vision
This system gives the experimenter great flexibility to present spatio-temporal stimulation patterns to a subject. A video configuration file (VCF) editor allows the experimenter to determine the electrical stimulation parameters for each electrode. A Pattern Stimulation software program allows direct stimulation of chosen patterns of electrodes, scaled by the subject's VCF, through a Graphical User Interface. The subject then responds by drawing the outline of the phosphene he or she perceives on a touchscreen. The Pattern Stimulation program saves all of the trial parameters and the parameters of an ellipse fit to their drawing, as well as a raw data file containing the input to the touchscreen is saved. After the experiment, offline image analysis can be performed to obtain a detailed quantitative description of the subject's percepts. Image descriptors can assigned to the touchscreen data; these image descriptors can be used to make formalized comparisons between various experimental conditions. Various types of image descriptors can be used, including simple ellipse fitting, projections of the 2-D drawings onto one-dimensional axes, calculations of Hu moments, PCA, and ICA.
1. A method of measuring electrically induced vision comprising:
providing a visual prosthesis including:
a neural stimulator having a plurality of electrodes suitable to stimulate visual neurons,
a visual user interface including a drawing input device; and
an operational control device controlling the neural stimulator and the visual user interface;
selecting and stimulating a stimulation pattern including a subset of said plurality of electrodes;
stimulating a patient, using the neural stimulator with the stimulation pattern creating a patent response;
collecting the patient responses in the operation control device via the patient drawing their perception of the stimulation pattern on the drawing input device;
analyzing a relationship of the stimulation pattern and the patient response in the operational control device; and
adjusting the visual prosthesis according to the relationship.
2. The method according to claim 1 , further comprising creating and storing a map of the relationship of the stimulation pattern and the patient response; and creating a perception of a visual image using the map.
3. The method according to claim 1 , wherein the drawing input device is a touch sensitive surface.
4. The method according to claim 3 , wherein the touch sensitive surface is also a display providing feed back of the patient response.
5. The method according to claim 1 , wherein the step of analyzing a relationship of the stimulation pattern and the patient response in the operational control device includes ellipse fitting to fit the patient responses to stimulation patterns.
6. The method according to claim 1 , wherein the step of analyzing a relationship of the stimulation pattern and the patient response in the operational control device includes Hu moments to fit the patient responses to stimulation patterns.
7. The method according to claim 1 , wherein the step of analyzing a relationship of the stimulation pattern and the patient response in the operational control device includes projections of two dimensional drawings on one dimensional axes to fit the patient responses to stimulation patterns.
8. The method according to claim 1 , wherein the steps selecting, stimulating and collecting are repeated multiple times and the step of analyzing involves averaging results of the multiple times.
9. The method according to claim 1 , wherein the step of analyzing a relationship of the stimulation pattern and the patient response in the operational control device includes principle component analysis to fit the patient responses to stimulation patterns.
10. The method according to claim 9 , wherein the step of analyzing a relationship of the stimulation pattern and the patient response in the operational control device includes independent component analysis to fit the patient responses to stimulation patterns.