Cochlear Nucleus Aqua+

The main function and benefit of Aqua+ is to provide Cochlear implant recipients with the ability to hear while swimming and bathing, which has previously not been possible. Waterproofing is achieved by encasing the sound processor in a soft, form fitting enclosure and connecting through this enclosure to a specialised waterproof coil. This allows prolonged use in water as deep as 3m, in environments such as ocean, chlorinated pool and bath water.

The main body of the sleeve is manufactured from self-adhesive Liquid Silicone Rubber (LSR), which comprises the overall covering, as well as forming the seals. Each seal area is reinforced and given structure by hard nylon parts, which the self-adhesive LSR bonds to in a high temperature over-moulding process. The self-adhesive nature of this particular LSR allows bonding to occur without the introduction of potentially bio-incompatible materials. Making the main constituent material soft also means that the waterproof covering can be made to be tightly form fitting. Additionally, it means that it is small and very comfortable to wear.

Aqua+ is designed to be form fitting to the sound processors it protects. This results in a design which is as small as possible, which improves retention and reduces irritation for the user, while also ensuring an aesthetically pleasing appearance. The resulting end shape, being familiar to users of Cochlear sound processors, ensures that usability of the final assembly is as simple as it can be. Aqua+ is also designed to fit the previous generation of sound processors (Nucleus 5), allowing existing recipients access to these benefits without the need for an upgrade.

The use of Liquid Silicone Rubber allows the sleeve to be form fitting to the sound processor, which minimises bulk, as well as improving aesthetics, comfort and retention. To overcome LSR's natural tendency to grip objects that are form fitting to it, the inner surface of the sleeve was designed to have a textured, roughened surface, defined to a specific EDM (electrical discharge machining) finish, as well as a series of protruding features. Together, the surface finish and protrusions reduce friction, allowing the smooth insertion and removal of the sound processor. These protrusions also provide an aesthetic benefit, giving the appearance of water droplets when viewed from the outside.

The Aqua+ allows users to waterproof their sound processors by totally encasing them, including their microphones. Consequently, this design incorporates a means of transferring sound across a physical barrier. Liquid Silicone Rubber can mould reliably to a very thin thickness, as low as 50 microns over a small area. This property is used to create a thin, sound permeable membrane just above the microphones, which allows uninterrupted sound transmission from outside the sleeve to the microphones. Additionally, the design of Aqua+ is such that it is small and comfortable enough to be worn on the ear, which is the optimal position for hearing performance.

Aqua+ incorporates a coil designed specifically to provide waterproofing capabilities in the smallest form factor possible, without the use of additional protective covers. This configuration is not only aesthetically pleasing, but also avoids the introduction of additional material between the coil and the implant, which is important for optimal transmission of signal between sound processor and implant. Waterproofing is achieved by the over-moulding of a compatible material onto the coil assembly and the use of tortuous paths to ensure water cannot reach electronic components. The resulting Aqua+ coil is extremely robust and durable.