Fig 1.
Illustration of the implanted Codacs system.
(CC-BY by courtesy of Cochlear Ltd.).
Fig 2.
Section view of the Codacs actuator.
(CC-BY by courtesy Cochlear Ltd.).
Fig 3.
(A) Codacs actuator without AI perpendicular to the RW membrane. (B) Bell prosthesis (BP) crimped to the Codacs actuator AI and coupled to the exposed stapes head. Reflectors were placed on stapes footplate and round window (RW). (C) Omega connector (OC) placed between the remains of the stapes crura (SC) together with the Aerial prosthesis (AP) connected to the actuator AI. (D) K-piston (KP) inserted into the inner ear through a SFP fenestration after immobilization of the SFP by ionomer cement (IC).
Fig 4.
SFP displacement responses to sound of TBs used for experiments (N = 10).
The black dashed lines depict the limits given by Rosowski et al. [11].
Fig 5.
Eq. sound pressure output level (N = 9) of Codacs stimulation with the Bell prosthesis at the SH for nominally 1 Vrms actuator input voltage.
Fig 6.
Eq. sound pressure level output (N = 8) of Codacs stimulation with the Omega/Aerial prosthesis at the SFP for nominally 1 Vrms actuator input voltage.
Fig 7.
Eq. sound pressure level output (N = 10) obtained in Codacs stimulation of the RW membrane at nominally 1 Vrms actuator input voltage.
Fig 8.
Eq. sound pressure level outputs (N = 10) of Codacs stimulation through a SFP fenestration with a K-piston at nominally 1 Vrms actuator input.
Data having SNRs < 10 dB was omitted (TB12 and TB21 at 125 Hz).
Fig 9.
Mean values and standard deviations (error bars) of the equivalent sound pressure levels [eq. dB SPL] generated by Codacs actuator stimulation at 1 Vrms for the four investigated stimulation modes.
At all frequencies the stimulation efficiency of Bell prosthesis stimulation at the stapes head (■) and of Omega/Aerial prosthesis stimulation at the SFP (◆) was statistically significantly higher than direct perilymph stimulation (▲) with the K-piston and direct RW stimulation (●).
Table 1.
Mean equivalent output levels and standard deviations of all stimulation modes tested.
Table 2.
Statistical analysis of differences in eq. output level [eq. dB SPL].
Fig 10.
Equivalent sound pressure levels obtained by oval window stimulation with the Bell prosthesis using either the RW displacements (■) or the SFP displacements (◆) in response to sound and actuator as reference.
Mean values and standard deviations (error bars) of eq. sound pressure level are shown for nominally 1 Vrms actuator input.