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tion have also been reported for this device, and CI-alone
performance was shown to be comparable to that achieved
by conventional recipients (16). These outcomes are
reviewed in more detail below.
The most recent EAS hardware from Cochlear Ltd includes
a new atraumatic electrode, the “Slim Straight” (SS) array,
which has been coupled to the CI24RE and CI500 Profile
implant packages to form the Nucleus CI422 and CI522
devices respectively (Figure 1). The SS array is a thin, flex-
ible straight electrode array that may be inserted through
either a cochleostomy or the round window and takes up
a position along the lateral wall of the cochlea. The elec-
trode carrier supports half-banded electrode contacts,
which gives the array a smooth side which significantly
reduces insertion forces and may reduce trauma when
moved along the lateral wall of the scala tympani (ST).
The 22 electrode contacts are distributed over 20mm and
the array has two markers, designed to indicate insertion
depths of 20 or 25mm. An insertion depth of 20mm is
recommended when hearing preservation is an issue, such
as with potential users of EAS.
The CP900 series Sound Processors (CP910 and CP920) may
optionally be fitted with the “acoustic component” (ACO)
unit, which replaces the standard earhook and incorporates
an acoustic transducer (receiver) which delivers its output
directly to the ear canal. This development enables the use
of a single integrated device, rather than the need for sepa-
rate electrical and acoustic stimulation units (Figure 2A).
A further advantage of an integrated unit is that electrical
and acoustic output adjustments can easily be made within
a single fitting system (Custom Sound software), allowing
optimal fitting of the EAS system (Figure 2B).
figure 1. CI522 internal implant
figure 2. CP910 sound processor
[REV. MED. CLIN. CONDES - 2016; 27(6) 776-786]
(A) and detail of the Slim-Straight electrode array (B), showing insertion depth markers.
A) The CP910 Sound Processor coupled to the acoustic component (ACO) fitted with dome ear canal insert. B) Integrated EAS fitting software (Custom Sound).