Abstract: Methods and devices for fitting a visual prosthesis are described. In one of the methods, threshold levels and maximum levels for the electrodes of the prosthesis are determined and a map of brightness to electrode stimulation levels is later formed. A fitting system for a visual prosthesis is also discussed, together with a computer-operated system having a graphical user interface showing visual prosthesis diagnostic screens and visual prosthesis configuration screens.

Abstract: In electrically stimulating neural tissue it is important to prevent over stimulation and unbalanced stimulation which would cause damage to the neural tissue, the electrode, or both. It is critical that neural tissue in not subjected to any direct current or alternating current above a safe threshold. Further, it is important to identify defective electrodes as continued use may result in neural and further electrode damage. The present invention presents system and stimulator control mechanisms to prevent damage to neural tissue.

Abstract: The invention is a method of automatically adjusting an electrode array to the neural characteristics of an individual subject. The response to electrical neural stimulation varies from subject to subject. Measure of impedance may be used to predict the electrode height from the neural tissue and, thereby, predict the threshold of perception. Alternatively, electrode height may be measured directly to predict the threshold of perception. Also, impedance measurement may be used to quickly identify defective electrodes and proper electrode placement.

Abstract: A process for the hydrogenation of a hydrocarbon feed includes contacting a major amount of the hydrocarbon feed with hydrogen in a counter-current manner in a first reaction zone under hydrogenation reaction conditions in the presence of a hydrogenation catalyst in at least a first catalyst bed wherein a liquid effluent exits at a bottom end of the first reaction zone and a hydrogen-containing gaseous effluent exits at a top end of the first reaction zone, and contacting a minor portion of the hydrocarbon feed with said hydrogen-containing gaseous effluent in a co-current manner in a second reaction zone having a catalyst bed positioned to receive the hydrogen-containing effluent of the first reaction zone.

Abstract: The present invention is a method of neural stimulation and more specifically an improved method of providing flexible video/image possessing in a visual prosthesis by providing downloadable video filters. In a visual prosthesis, the input video image will, for the foreseeable future, be higher resolution than the output stimulation of the retina, optic nerve or visual cortex. This is due to limits of electrode array technology and the rapid advancement of video camera technology. It is therefore, advantageous to apply video processing algorithms (filters) to help provide the most useful information to the lower resolution electrode array. Different filters are more effective in different environments and for different subjects. Furthermore, filters will continue to improve over time. Examples of situation dependent filters include reverse image, contrast increasing, edge detection, segmentation using chromatic information and motion detection.

Abstract: The present invention is a method of improving the persistence of electrical neural stimulation, and specifically a method of improving the persistence of an image supplied to a retina, or visual cortex, through a visual prosthesis. A continuously stimulated retina, or other neural tissue, will desensitize after a time period in the range of 20 to 150 seconds. However, an interruption of the stimulation on the order of a few milliseconds will restore the retinal sensitivity without the user perceiving the interruption, or with the user barely perceiving the interruption.

Abstract: The invention is a method of automatically adjusting an electrode array to the neural characteristics of an individual patient. The perceptual response to electrical neural stimulation varies from patient to patient and The response to electrical neural stimulation varies from patient to patient and the relationship between current and perceived brightness is often non-linear. It is necessary to determine this relationship to fit the prosthesis settings for each patient. It is advantageous to map the perceptual responses to stimuli. The method of mapping of the present invention is to provide a plurality of stimuli that vary in current, voltage, pulse duration, frequency, or some other dimension; measuring and recording the response to those stimuli; deriving a formula or equation describing the map from the individual points; storing the formula; and using that formula to map future stimulation.

Abstract: The present invention is a method of improving the persistence of electrical neural stimulation, and specifically a method of improving the persistence of an image supplied to a retina, or visual cortex, through a visual prosthesis. A continuously stimulated retina, or other neural tissue, will desensitize after a time period in the range of 20 to 150 seconds. However, an interruption of the stimulation on the order of a few milliseconds will restore the retinal sensitivity without the user perceiving the interruption, or with the user barely perceiving the interruption.

Abstract: A process for the hydrogenation of a hydrocarbon feed includes contacting a major amount of the hydrocarbon feed with hydrogen in a counter-current manner in a first reaction zone under hydrogenation reaction conditions in the presence of a hydrogenation catalyst in at least a first catalyst bed wherein a liquid effluent exits at a bottom end of the first reaction zone and a hydrogen-containing gaseous effluent exits at a top end of the first reaction zone, and contacting a minor portion of the hydrocarbon feed with said hydrogen-containing gaseous effluent in a co-current manner in a second reaction zone having a catalyst bed positioned to receive the hydrogen-containing effluent of the first reaction zone.