Telemetry changes over time in cochlear implant patients

Abstract

Objectives: This is a cross-sectional study conducted on cochlear implant recipients, to monitor changes in recorded impedance telemetry and evoked compound action potentials (ECAP) measured during surgery versus the same measures at post implant follow-up visits. An additional aim was to correlate the recorded ECAP measures with the patient ' s postoperative performance and to evaluate the incidence of abnormal intra-operative cochlear implant telemetry measurements and their changes at device activation. Study design: The present study comprised 44 subjects -12 adults and 32 children of both genders -implanted at the Cochlear Implant Unit, Cairo University. ECAP thresholds and electrode impedance measures were collected intra-operatively, at initial stimulation, and at 9 -12 months post initial stimulation. Measurements were compared at the three intervals and ECAP measures were correlated to the patient ' s post-operative performance in the form of aided sound fi eld thresholds, speech detection and discrimination for adults and language assessment for children. Results: In the absence of electrical stimulation, there was an increase of impedance on all electrodes at the initial stimulation visit, which decreased at the 9 -12 months follow-up. Open circuit fi ndings were more prevalent than short circuits. Children had higher impedance values at post implant activation compared to adult patients. No correlation existed between ECAP thresholds and post-operative patient performance at the one-year evaluation. Conclusion: At the time of surgery, telemetry provides valuable information regarding the electrical output of the implant and the response of the auditory system to electrical stimulation; however, it is not a valuable predictor of post-operative performance.

Systematic review of compound action potentials as predictors for cochlear implant performance

“…After the removal of duplicates and screening of titles and abstracts, 143 remained. Evaluation of full texts yielded a total of 26 articles and cross‐referencing added one, resulting in a total of 27 relevant articles suitable for critical appraisal describing a relation between speech perception of cochlear implantees and characteristics of the recorded eCAPs.…”

“…Basta et al (2007) was excluded because of the not solely electrophysiological parameter that was correlated to speech perception; a correlation between a psychophysical parameter and the electrophysiological parameter was used . The remaining 25 articles were eligible for further analysis …”

“…Cosetti et al (2010) concluded there was no significant association of speech perception in adults and children 1 year after implantation with threshold neural response telemetry (tNRT) . El Shennawy et al (2015) concluded the same for their adult CI subjects . Four other studies did not report significance data, but simply stated they found no significant correlation .…”

“…Seven studies make a statement about eCAP threshold, the minimum stimulus level at which an eCAP can be recorded. 7,[10][11][12]19,20,32 Cosetti et al (2010) concluded there was no significant association of speech perception in adults and children 1 year after implantation with threshold neural response telemetry (tNRT). 10 El Shennawy et al (2015) concluded the same for their adult CI subjects.…”

“…6 The remaining 25 articles were eligible for further analysis. [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][23][24][25][26][27][28][29][30][31][32]…”