Long-Term Impedance Trend in Cochlear Implant Users with Genetically Determined Congenital Profound Hearing Loss

Time course of transimpedances is affected by cochlea implant surgical technique

BACKGROUND

For cochlear implant (CI) users after subtotal cochlectomy for removal of intracochlear schwannomas, significantly different intracochlear potentials can be observed compared with cochleae of CI patients after round window electrode insertion. The time course of this difference after surgery is so far unknown.

PURPOSE

The change of intracochlear potentials over time and differences between surgical approaches are investigated.

METHODS

In a retrospective study of cochlear implant recipients, the electrode transimpedances were measured and compared between 19 patients after subtotal cochlectomy and 20 patients after round window insertion. Transimpedances were measured with pulse widths of 37 µs and current units of 100 CL to 110 CL using a monopolar stimulation and recording mode (MP2). For each patient, at least three time points over a period of up to four years were used for time course analysis.

RESULTS

The transimpedances of patients after subtotal cochlectomy were significantly smaller than those of the round window group. The largest transimpedance changes over time were observed for basal electrode contacts in patients after round window insertion.

CONCLUSIONS

For the interpretation of transimpedances, it is relevant to consider the time since surgery and the CI insertion technique. The width of the electric field may be related to loss of intracochlear conductive fluid due to surgical trauma and fibrotic processes.

Remote Check as a tele-health instrument for cochlear implant recipients: Analysis of impact and feasibility of application

PURPOSE

The number of cochlear implant (CI) surgeries is growing over time, with the risk of overloading CI centers in the post-surgical management. Telemedicine is a possible solution to address this phenomenon. Remote Check (RC) is an application that is specific for CI recipients monitoring. The aim of this study is to evaluate the feasibility of application, potential economic impact and patients' acceptance of RC.

METHODS

The study is retrospective investigation, data on clinical, audiological features (from remote and on-site evaluation), and satisfaction surveys of 66 consecutive patients were collected; costs required for RC and for on-site evaluations were recorded as well.

RESULTS

One hundred and ninety RC sessions were completed by the patients (2.88 sessions per patient). RC and on-site audiometry significantly correlated except for the 500 Hz frequency. Estimated costs for the Italian National Health System for RC review and on-site evaluations were 1.32€ and 3.49€ per minute, respectively. High satisfaction for RC was reached in 91 % of patients.

CONCLUSION

RC revealed to be a reliable, cost-effective and well accepted tool in CI monitoring. This study preliminarily supports the hypothesis that RC could be a valid instrument to reduce CI management overload in the outpatient clinic.

Intraoperative Measurement of Insertion Speed in Cochlear Implant Surgery: A Preliminary Experience with Cochlear SmartNav

OBJECTIVES

The objectives were to present the real-time estimated values of cochlear implant (CI) electrode insertion speed (IS) during intraoperative sessions using the Cochlear Nucleus SmartNav System to assess whether this measure affected CI outcomes and to determine whether real-time feedback assists expert surgeons in achieving slow insertion.

METHODS

The IS was measured in 52 consecutive patients (65 implanted ears) using the CI632 electrode. The IS values were analyzed in relation to procedure repetition over time, NRT ratio, and CI audiological outcomes.

RESULTS

The average IS was 0.64 mm/s (SD = 0.24); minimum and maximum values were 0.23 and 1.24 mm/s, respectively. The IS significantly decreased with each array insertion by the operator (p = 0.006), and the mean decreased by 24% between the first and last third of procedures; however, this reduction fell within the error range of SmartNav for IS (+/-0.48 mm/s). No correlation was found between IS and the NRT ratio (p = 0.51), pure-tone audiometry (PTA) at CI activation (p = 0.506), and PTA (p = 0.94) or word recognition score (p = 0.231) at last evaluation.

CONCLUSIONS

The estimated IS reported by SmartNav did not result in a clinically significant reduction in insertion speed or an improvement in CI hearing outcomes. Real-time feedback of IS could potentially be used for training, but its effectiveness requires confirmation through additional studies and more accurate tools. Implementation of IS assessment in clinical practice will enable comparisons between measurement techniques and between manual and robot-assisted insertions. This will help define the optimal IS range to achieve better cochlear implant (CI) outcomes.