Cochlear implant devices

Abstract

An improved cochlear implant and method of stimulating are disclosed. The method comprises stimulating an electrode array using a set of current stimuli having different geometries, so as to provide a more regular and monotonic set of pitch percepts for a user. In one embodiment, this may be achieved by combining different modes of stimulation for a patient, so that some channels utilise one mode and other channels utilise one or more different modes,

1 . An improved method of stimulating a cochlear prosthesis, said prosthesis comprising an electrode array including a plurality of individually addressable electrodes, and a stimulator device adapted to provide electrical stimuli to selected groupings of said electrodes in response to sound signals, said stimuli and the corresponding groupings of electrodes being determined by reference to a predefined instruction set, 
 characterised in that in response to different sound signals at least two distinct current distribution geometries may be induced in the auditory structures of a user.    
     
     
         2 . A method according to  claim 1 , wherein said different current distribution geometries are induced by one or a combination of factors selected from the group comprising: 
 selection of different modes of stimulation; and    use of different electrode geometries.    
     
     
         3 . A method according to  claim 1  or  claim 2 , wherein said electrodes are grouped into at least two groups, and the electrode or electrodes in each said group are stimulated using different stimulation modes.  
     
     
         4 . A method according to  claim 1  or  claim 2 , wherein one or more electrodes in one or more groups of said electrodes in the electrode array have a differing geometry to the electrode or electrodes in another group of said electrodes in the electrode array.  
     
     
         5 . A method according to any one of the preceding claims, wherein said electrode array includes at least one extra-cochlear electrode.  
     
     
         6 . An auditory prosthesis, comprising an electrode array including a plurality of individually addressable electrodes, and a stimulator device adapted to provide electrical stimuli to selected groupings of said electrodes in response to sound signals, said stimuli and the corresponding groupings of electrodes being determined by reference to a predefined instruction set, 
 characterised in that in response to different sound signals at least two distinct current distribution geometries may be induced in the auditory structures of a user.    
     
     
         7 . A prosthesis according to  claim 6 , wherein said different current distribution geometries are induced by one or a combination of factors selected from the group comprising: 
 selection of different modes of stimulation; and    use of different electrode geometries.    
     
     
         8 . A prosthesis according to  claim 6  or  claim 7 , wherein said electrodes are grouped into at least two groups, and the electrode or electrodes in each said group are stimulated using different stimulation modes.  
     
     
         9 . A prosthesis according to  claim 6  or  claim 7 , wherein one or more electrodes in one or more groups of said electrodes in the electrode array have a differing geometry to the electrode or electrodes in another group of said electrodes in the electrode array.  
     
     
         10 . A prosthesis according to any one of  claims 8  to  13 , wherein said electrode array includes at least one extra-cochlear electrode.