The importance of electrically evoked stapedial reflex in cochlear implant

Comparison of electrically evoked stapedial reflexes in patients with cochlear implants surgically implanted using Veria and posterior tympanotomy approaches

OBJECTIVE

The study aimed to compare ipsilateral and contralateral electrically evoked stapedial reflex thresholds in children with a unilateral cochlear implant surgically implanted either through Veria or posterior tympanotomy approaches.

METHODS

Forty-nine children using cochlear implants were studied, of whom 27 underwent the Veria approach and 22 underwent the posterior tympanotomy approach. The electrically evoked stapedius reflex thresholds were measured ipsilaterally and contralaterally by stimulating four equally spaced electrodes.

RESULTS

The ipsilateral electrically evoked stapedius reflex threshold was absent in all four electrodes in the children implanted using the Veria approach. However, the ipsilateral electrically evoked stapedius reflex threshold was present in 70 per cent of the children implanted using the posterior tympanotomy approach. The contralateral electrically evoked stapedius reflex threshold was present in most of the children for both surgical approaches.

CONCLUSION

The presence of the ipsilateral electrically evoked stapedius reflex threshold varies depending on the surgical technique used for cochlear implantation. However, contralateral reflexes are present in the majority of children using cochlear implants, irrespective of the surgical approach.

High Electrode Impedance Values in Pediatric Cochlear Implant Recipients May Imply Insufficient Auditory and Language Skills Development

Background: Measurements of electrode impedance values are routinely performed after cochlear implantation. The primary objective of the study was to determine if pediatric, prelingually deafened patients with different postoperative performances showed significantly different impedance values one year after implantation. Methods: This study comprised 42 pediatric cochlear implant recipients provided with the device in a single academic tertiary referral center between 1 January 2000, and 31 December 2016. Medical chart analysis was performed in order to assess evolution of impedance values during the first postoperative year on a monthly basis. Electrode impedance values measurements one year postoperatively were compared between children with successful and unsuccessful auditory and language skills development assessed using the EARS protocol (a name of a performance test). Furthermore, values were compared among recipients of different implant types and among different cochlear segments. Results: A gradual rise of average impedance values was found during the first months of implant use (1st month, 7.32 kΩ; 3rd month, 7.86 kΩ) with the peak at the 4th postoperative month (7.96 kΩ), followed by a gradual decrease towards the 12th month (6th month, 7.62 kΩ; 12th month, 6.86 kΩ). Lower values at the 12th postoperative month were observed in recipients with successful development compared to patients presented with unsuccessful development (6.22 kΩ vs. 7.82 kΩ; p = 0.001). Mean impedance values were different when compared among cochlear segments and among different implant types. Conclusion: High electrode impedance values one year after implantation in pediatric patients may imply insufficient auditory and language skills development. Further studies are needed in order to validate our results.

Cochlear Implantation for Children and Adults with Severe-to-Profound Hearing Loss

Cochlear implants (CIs) have proven to be a useful treatment option for individuals with severe-to-profound hearing loss by providing improved access to one's surrounding auditory environment. CIs differ from traditional acoustic amplification by providing information to the auditory system via electrical stimulation. Both postlingually deafened adults and prelingually deafened children can benefit from a CI; however, outcomes with a CI can vary. Numerous factors can impact performance outcomes with a CI. It is important for the audiologist to understand what factors might play a role and impact performance outcomes with a CI so that they can effectively counsel the recipient and their family, as well as establish appropriate and realistic expectations with a CI. This review article will discuss the CI candidacy process, CI programming and postoperative follow-up care, as well as considerations across the lifespan that may affect performance outcomes with a CI.

Evaluation of volatile and intravenous anesthetics, effects on the threshold of neuroresponse telemetry and the threshold of acoustically evoked stapedial reflex in children undergoing cochlear implant surgery

Background and Aims:

Congenital hearing loss affects about 1 in every 1000 live births. Cochlear implant is an effective therapeutic method for aural rehabilitation in children suffering from severe-to-profound hearing loss. The aim of this study was to compare the effects of the intravenous and inhalational anesthesia techniques on neuroauditory threshold and stapedial reflex threshold responses.

Material and Methods:

After approval of the university ethics committee and obtaining written informed parental consent, 110 children with severe or profound bilateral sensorineural hearing loss undergoing cochlear implant surgery were randomly divided in two groups. The effects of the total intravenous anesthesia (propofol and remifentanil) and inhalation anesthesia (sevoflurane) techniques were evaluated on the neuroauditory threshold and stapedial reflex threshold responses of patients. Variations in systolic and diastolic blood pressures and mean arterial blood pressure were measured in both groups.

Results:

No significant difference was observed in the following parameters: age, weight, duration of anesthesia, and surgery. No side effects was observed in the two groups. No significant difference was found in the Telemetry Neuroal Response Test (TNRT) reflex between the two groups (P = 0.294); however, the difference between the two groups was significant (P = 0.001) for Electrical Stapedial Reflex Threshold (ESRT) reflex. In the sevoflurane group, in 39 patients in the electrode 3 and in 17 patients in the electrode 9 (compared with 20 and 6 patients in the Propofol–remifentanil group) complete suppression of stapedial reflex existed.

Conclusion:

Our results suggest that, during the cochlear implant surgery, use of inhalation anesthetics should be avoided for achieving controlled hypotension because this may suppress or even fully eliminate stapedial reflex. Remifentanil and Propofol infusion has a slight effect on hearing thresholds and is recommended for determining hearing thresholds during cochlear implant surgeries.