Abstract: Improved reversibly expandable structures are formed from novel loop assemblies comprising a plurality of links, each of said links having at least one center pivot joint and a plurality of end pivot joints, each of at least two of said plurality of end pivot joints proximate to the outer edge of said loop assembly and connected to another link; each of said plurality of links being connected to another one of said plurality of links by at least two end pivot joints thereby forming a link pair, said loop assembly comprising at least three link pairs, each of said at least three link pairs connected to at least two other link pairs through at least one of said end pivot joints; each of said at least three link pairs connected to a central piece that is central to the loop assembly, said central piece being rotatable around a central axis, wherein the rotation of the central piece reversibly expands said loop assembly.

Abstract: A multi-bipolar configured electrode array and means to uniquely position said array within the scalae of the human cochlea is described. Said array is inserted into the scala tympani, scala vestibuli or both, by a surgeon. The electrode array may be pre-formed to lightly hug the modiolar wall of a scala so as to position the electrodes in close proximity to the cochlear spiral lamina and spiral ganglia in the modiolus. Mechanical features within said array allow the surgeon to further position said array against the modiolar wall of the scala, post insertion, and to mechanically retain such positioning of said array. Such positioning is in close proximity to surviving neural sites in the spiral lamina and/or spiral ganglion cells in the modiolus to efficiently stimulate functioning auditory neural elements. The multi-bipolar electrode configuration achieves a high degree of spatial selectivity, thus improving the implantee's speech percepts.