Comparison of the impedance measurements and neural response threshold with and without stylet in the nucleus contour cochlear implant

Abstract EN

Objective : to compare the impedance and neural response threshold levels in freedom contour advance nucleus cochlear implant before and after removal of stylet.

Material : fifty patients aged 1 to 12 years old of both sexes who were profoundly deaf in both ears with no benefit of hearing aids were included in the present study.

Methods : impedance threshold levels and neural response telemetry thresholds were recorded for each patient intra operatively before and after removal of stylet.

Results : there were significant differences (p < 0.05) between impedance measurements and neural response telemetry threshold levels before and after removal of stylet.

Conclusion : withdrawing the stylet results in a favorable position change of the electrode array within the scala tympani, so that it comes closer to the auditory nerve endings, a finding which is important in clinical setting when programming the system.

Removal of stylet results in lower impedance threshold and lower neural response telemetry threshold levels compared to results while stylet is inserted.

Therefore we recommend recording the impedances and neural response telemetry before removal of stylet to avoid displacement of electrode arrays before ensuring that the array is in the correct place, and to adopt the impedance and neural response telemetry thresholds after the removal of stylet for the purpose of programming the speech processor.