Electrode array configuration on a flexible substrate for electro-oculogram recording

#The present invention relates to a method for fabricating and positioning electrodes in an electrode array on a self-adhesive flexible substrate comprising a plurality of electrodes for measuring electrical signals during an electro-oculogram, particularly for tracking the gaze position and movement of the human eye.

#Measuring movements of the eyes or gaze tracking with high accuracy is a desirable objective in many areas of research, clinical practice and for consumer devices for human computer/machine interfacing. In recent years, head mounted video-oculography (VOG) systems have been used for a diverse range of eye/gaze tracking purposes. However, these systems require wearing a head mounted camera system that may be uncomfortable and cumbersome to wear for long periods, are difficult to wear along with corrective lenses, and not suitable for all recording environments. Additionally, they require a stable relationship with the head. Any abrupt movement of the head cameras that alters this fixed relationship introduces artifact. Any fogging of the camera lens can also alter the data. An alternative method of recording gaze and eye tracking movements is referred to as the electro-oculogram (EOG) which measures the measures electro-potential difference between the retina and the cornea which can be modeled as a dipole for each eyeball with the cornea having the positive end and the retina having the negative end of the dipole. The discrete nature of the EOG recording apparatus allows the subject to wear corrective lenses if necessary, or to use a head-mounted visual stimulus delivery system such as virtual reality goggles without obstruction. Plus there are some applications that are in the exclusive domain of EOG such as a component of sleep testing, biofeedback, and during electroencephalogram (EEG) testing.

#Another limitation of the VOG is the sampling rate afforded by most systems, typically from 30-60 Hz, VOG is a trade-off between high spatial resolution and weaker temporal frequency. EOG can be sampled at a significantly higher frequency, beyond 1000 Hz, depending on the amplified sampling rate. Thus EOG is the method of choice in conditions requiring fast sampling rate, for example, analyzing saccade eye movements or identifying early stages of oculomotor pathology in certain neurologic conditions.

#FIG. 1 illustrates an embodiment of the invention with a 14-channel electrode array configuration conforming the perimeter of the right eye;

#FIG. 2 is a frontal view of a human head illustrating a prior art EOG electrode placement for detecting eye movements where electrodes at locations A, B measures eyes' horizontal and C, D measures eyes' vertical movements;

#FIG. 3 illustrates one embodiment of the 14-channel electrode-array on a flexible substrate with plurality of electrodes positioned horizontally at roughly equal distance as illustrated as 100 in FIG. 3 to pick up electrical signals caused by vertical eye movements, and group of electrodes positioned to the side and corner of the eye 101 to remain sensitive to the eye movement in the horizontal direction, electrode positions for a ground electrode (GND) providing a common ground potential (0V) for the channels, and a reference electrode 102 which the EOG signals are measured against;

#The detailed description set forth below is intended as a description of the presently exemplified devices, methods and materials provided in accordance with aspects of the present invention, and it is not intended to represent the only forms in which the present invention may be practiced or utilized. It is to be understood, however, that the same or equivalent functions and components may be accomplished by different embodiments that are also intended to be encompassed within the spirit and scope of the invention.

#Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood to one of ordinary skill in the art to which this invention belongs. Although any methods, devices and materials similar or equivalent to those described herein can be used in the practice or testing of the invention, the exemplified methods, devices and materials are now described.

#The present invention relates to a method for fabricating and positioning electrodes in an electrode array on a self-adhesive flexible substrate comprising a plurality of electrodes for measuring electrical signals during an electro-oculogram (EOG), particularly for tracking the gaze position and movement of the human eye.