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Telemetry changes over time in cochlear implant patients

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Audiology Unit Cairo University

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Telemetry changes over time in cochlear implant patients Telemetry changes over time in cochlear implant patients Presentation Transcript

  • Telemetry Changes Over Time in Cochlear Implant Patients Thesis Submitted For Partial Fulfillment of the Master of Science Degree in Audiology By Sarah Mohamed Ibrahim Sheta
  • Acknowledgement  I am thankful to Allah for granting me the will and power to finish this work and to my parents who supported me through out my medical career.  I would like to express my appreciation to Prof. Dr. Mohamed Magued Mashaly, Professor of Otorhinolaryngology, Faculty of Medicine, Cairo University, for his share of experience and guidance in the production of this work.  I would like to express my deepest gratitude and cardinal appreciation, to Professor Dr. Mohamed Ibrahim Shabanna, Professor of Audiology, Faculty of Medicine, Cairo University for his great support, valuable guidance and advice, and continuous help and encouragement.
  • Acknowledgement, cont.  I am also sincerely grateful to Assistant Prof. Dr. Amira El Shennawy, Assistant Professor of Audiology, Faculty of Medicine, Cairo University, for her generous assistance, great help, valuable advice, and sacrifice of much of her precious time to make this work possible.  I am obliged to the staff members of the Audiology Unit, Cairo University, for the valuable information and the support provided by them.
  • Introduction  Cochlear implants are among the great success stories of modern medicine.  Thirty years ago these devices provided little more than a sensation of sound, allowing for improvements in lip reading ability, now the majority of patients are achieving more than 80% on open-set speech recognition tasks.  Today over 300,000 patients have undergone implantation worldwide, and cochlear implantation has become the standard of care for hearing rehabilitation in patients with severe to profound sensorineural hearing loss (SNHL).
  • Introduction, cont.  The success of the implant and satisfaction of the patient are highly dependant on many factors, one of them is the appropriateness of the speech processor programming, because it is the map that determines the sound and which characteristics are codified.  Thus, objective measures have been studied and employed to predict the levels of stimulation for the construction of the first maps and also for the verification of the integrity of the whole system. It is natural that these levels undergo changes throughout time.
  • Introduction, cont.  The electrically evoked compound action potential (ECAP), and Electrode Impedance which can be assessed by telemetry are of those objective measures.  Telemetry has become increasingly important as a means to monitor the correct functioning of the external and internal hardware, to assess the electrical impedance , as well as to record the ECAP thresholds.
  • Aim of the work 1. The Value of intra-operative telemetry measurements in predicting cochlear implant recipient performance. 2. Determine the reliability of intra-operative Neural Response Telemetry measurement in predicting postoperative psycho- electric parameters. 3. To evaluate the incidence of abnormal intra-operative cochlear implant telemetry measurements and their changes at device activation.
  • Materials and Methods
  • A) Subjects  The study included 44 patients, 12 adults and 32 children, who received cochlear implantation at Kasr Al- Ainy hospitals in the period between January 2011 to January 2013.  Twenty four patients (6 adults and 18 children ) were implanted with Cochlear Nucleus M implant, using (Sprint/ESPrit or Freedom) speech processor and are using ACE speech strategies.  Twenty patients ( 6 adults and 14 children) were implanted with MED-EL SONATA implant, using OPUS 2 speech processor and are using FS4 speech strategy.
  •  Puretone audiometer: GSI model 61,  Sound treated room ( Amplisilence Model E)  A laptop computer with the Cochlear corporation programming interface ( Custom Sound EP)  A laptop computer with the MED-El corporation programming interface (Maestro 4). B) Equipment
  • Methods  Data were collected using the electronic patient records from the manufacturers' clinical software and/or the audiologist's intraoperative and postoperative reports. A) Electrode Impedance B) ECAP Measures C) Post Operative Assessment D) Data Analysis
  • A) Electrode Impedance I-Intraoperative Impedances:  Were measured on all electrodes after electrode insertion and before the electrically evoked compound action potential was measured. Impedances were measured using the manufacturers’ default modes: common ground (CG) and all 3 monopolar modes (MP1, MP2, or MP1+2) for Cochlear devices, and monopolar mode for MED-EL devices II-Postoperative Impedances:  Were measured at the beginning of the initial-activation appointment and at the 9-12 months postimplant follow up visit
  • B) ECAP Measures I- The Intra operative NRT/ART  NRT was performed using the Custom Sound EP.2 Software included with the Nucleus 24M device.  ART was performed using the Maestro. 4 Software included with the MED-EL Sonata device.  The audiologist obtains ECAP measurements from 4 electrodes: E5, E10, E15, and E20 for the Nucleus 24 M Implants and from 6 electrodes: E2, E4, E6, E8, E10 and E12 for the MED-EL Implants.
  • B) ECAP Measures, cont.  Lack of ECAP response on any electrode or a T-NRT level of 0 was not excluded from analysis, but rather included in the data set as no response. II-The post operative NRT/ ART  NRT/ART was collected during the 9-12 months postimplant visit .
  • C) Post Operative Assessment  After implantation, subjects were evaluated with the speech processor settings used by each patient.  Aided Free Field, Aided thresholds to warable tones were obtained at frequencies 500-4000 Hz.  For adults, Word Discrimination with and without visual cues was performed  For children, language assessment was done to estimate language age before implantation and then every 6 months post implantation to assess child's language progress.
  • D) Data Analysis  Statistical presentation and analysis of the present study was conducted, using the mean, standard error, student t- test, Paired t-test and Linear Correlation Coefficient by SPSS V17.
  • Results
  • Demographic data of adults and children TotalChildAdult %N%N%N 52.272353.131750.006Male Sex 47.732146.881550.006Female 45.452043.751450.006MED-EL Device 54.552456.251850.006CI24 2.00-47.002-618-47Range Age at implantation, (years) 11.20±11.904.47±1.0529.17±8.17Mean±SD 0.16-23.000.16-6.002-23Range Duration of Hearing loss, (years) 5.02±4.054.03±1.587.67±6.83Mean±SD
  • Etiology of hearing loss for adults and children Group Etiology TotalChildAdult %N%N%N 38.641731.251058.337Unknown 6.8233.13116.672Fever 6.8230.00025.003Autoimmune 38.641753.13170.000Congenital 6.8239.3830.000Menengitis 2.2713.1310.000Otoxicity 100.0044100.0032100.0012Total
  • A) Post-Operative Performance of Children Paired Samples TestPaired Differenceslanguage age (Months) P-valuetSDMeanSD±MeanRange <0.001*-9.0456.684-10.688 1.260±6.6569.000-6.000Pre operative 7.533±17.34430.000-9.000Post operative 0 5 10 15 20 25 30 Pre operative Post operative Languageage(Months) Mean and range of Language Age (Months) preoperatively and postoperatively
  • Mean and SD of Unaided FF and Aided CI Response for children Paired Samples TestPaired DifferencesAided CI response (dB)UnAided FF (dB) Frequency (Hz) P-valuetSDMeanSD±MeanSD±Mean <0.001*14.90611.62230.62511.622±39.3750.000±70.000500 <0.001*18.10412.01138.43812.011±41.5630.000±80.0001000 <0.001*15.37713.85337.65613.853±42.3440.000±80.0002000 <0.001*11.47513.78827.96913.788±42.0310.000±70.0004000 0 10 20 30 40 50 60 70 80 90 500 1000 2000 4000 Frequancy(Hz) Hearinglevel(dBHTL) Un Aided FF Aided Ci response Unaided FF and Aided CI response in children
  • B) Post-operative performance of Adults Paired Samples TestPaired Differencespostoperativepreoperative P-valuetSDMeanSD±MeanSD±Mean <0.001*-6.67225.595-548.099±87.625.413±28Aided WDS withVC% <0.001*-6.8622.505-46.54523.479±49.4554.924±2.667Aided WDS without VC% -20 0 20 40 60 80 100 120 Pre Post Percentage(%) WDS eVC WDS eout VC Mean and Standarad Deviation of WDS with and without Visual cues
  • Mean and SD of Pre-operative PTA and Aided CI response for adults Paired t-testdifferenceAided CI response (dB)Pre operative PTA (dB) Frequency (HZ) P-valuetSDMeanSD±MeanSD±Mean ±6.686±95.833250 <0.001*19.66213.72877.91712.990±36.2507.930±114.167500 <0.001*24.41111.76682.91711.766±37.0830.000±120.0001000 <0.001*19.17014.53280.41714.532±39.5830.000±120.0002000 <0.001*20.37914.59085.83314.590±34.1670.000±120.0004000 ±0.000±100.0008000
  • Pre-operative PTA and Aided CI response in adults 0 20 40 60 80 100 120 140 250 500 1000 2000 4000 8000 Frequancy (Hz) Hearinglevel(dBHTL) Pre operative PTA Aided Ci response
  • C) Intraoperative Impedance Versus Postopetartive Impedance Paired Samples TestPaired DifferencesCI24 P-valuetSDMeanSD±MeanRange <0.001*-37.5911.374-2.2641.536±4.33511.000-1.600 Impedance 1 (Kohm) <0.001*-22.3720.609-0.5972.114±6.59914.000-2.200 Impedance 2 (Kohm) <0.001*32.3441.1761.6671.501±4.93211.500-2.200 Impedance 3 (Kohm) Mean, Standard Deviation and Range of Electrode impedance Values in CI24 Device
  • Mean Electrode impedance change over time in CI24 device 0 1 2 3 4 5 6 7 8 9 10 Impedance 1 Impedance 2 Impedance 3 Impedancevalue(Kohm)
  • Average values of each active Electrode impedance measured in subjects implanted with CI24 Devices in the three studied time intervals 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 Electrode Impedancevalue(Kohm) Impedance 1 Impedance 2 Impedance 3 CI24
  • Mean, Standard Deviation and Range of Electrode impedance Values in Med-El Device Paired Samples TestPaired DifferencesMED-EL P-valuetSDMeanSD±MeanRange <0.001*-12.4692.165-1.7461.843±5.15611.900-2.300 Impedance 1 (Kohm) <0.001*-2.0250.898-0.1182.264±6.90214.070-2.350 Impedance 2 (Kohm) <0.001*13.0021.9361.6281.601±5.27412.000-2.300 Impedance 3 (Kohm)
  • Mean Electrode Impedance change over time in Med- el Device 0 1 2 3 4 5 6 7 8 9 10 Impedance 1 Impedance 2 Impedance 3 Impedancevalue(Kohm)
  • Average values of each active Electrode impedance measured in subjects implanted with Med-El Devices in the three studied time intervals 0 1 2 3 4 5 6 7 8 9 10 0 1 2 3 4 5 6 7 8 9 10 11 12 Electrode Impedancevalue(Kohm) Impedance 1 Impedance 2 Impedance 3 MED-EL
  • D) Incidence of abnormal electrodes Impedance  The total incidence of devices with at least 1 electrode with abnormal impedance (OC/SC) across the 2 devices intra operatively was 9 % (4 devices out of 44 device) 75 % of abnormalities were OC (3/4) where 25 % (1/4) were SC.  They remained the same post operatively
  • E) Intraoperative ECAP versus Postoperative ECAP Recorded ECAP intraoperative and postoperative in Med-El and CI24 device CI24MED-EL %N%N 81.2578/9651.6662/120Intraoperative 18.7518/9648.3358/120Postoperative
  • Mean and Standard Deviation for intraoperative and postoperative ECAP threshold for Med-El device Paired Samples TestPaired Differences Postoperative ECAP Threshold (CU) Intra operative ECAP Threshold (CU) MED-EL P-valuetSDMeanSD±MeanSD±Mean 0.3540.978324.743100.400119.832±681.400281.752±781.800E2 0.012*3.365203.751242.375232.119±717.375185.019±959.750E4 0.6490.483307.57060.667182.802±791.667169.614±852.333E6 0.557-0.629282.366-72.500126.902±795.833362.850±723.333E8 0.1161.763303.768178.556219.532±722.222273.435±900.778E10 0.3201.084250.239102.571244.949±800.000138.755±902.571E12
  • Mean and standard deviation for intraoperative and postoperative ECAP threshold for CI24 device Paired Samples TestPaired Differences Postoperative ECAP Threshold (CU) Intra operative ECAP Threshold (CU) CI24 P-valuetSDMeanSD±MeanSD±Mean 0.2951.07853.18213.15864.409±179.73786.447±192.895E5 0.1601.46672.78024.47464.289±179.47472.659±203.947E10 0.0911.783257.143102.50074.084±169.000262.829±271.500E15 0.3360.98784.97518.75072.038±165.00094.797±183.750E20
  • Correlation between intra operative and post operative ECAP thresholds with postoperative performance in Med-El Device LANGUAGE AGE (years) Aided WDS without VC % Aided WDS withVC % Aided SDT (dB) Aided CI response (dB)MED-EL P-valuerP-valuerP-valuerP-valuerP-valuer 0.730.130.700.450.100.990.58-0.170.39-0.26IntraE2 0.87-0.07.1.00.1.000.68-0.140.49-0.23IntraE4 0.750.170.73-0.410.670.500.20-0.470.31-0.39IntraE6 0.08-0.75.-1.00.-1.000.410.340.750.13InraE8 0.59-0.230.100.900.570.430.670.140.790.08IntraE10 0.140.57.1.00.1.000.32-0.350.10-0.55IntraE12 0.16-0.450.45-0.760.290.900.760.090.360.27PostE2 0.41-0.300.130.870.300.700.13-0.420.08-0.48PostE4 0.700.140.740.260.090.910.08-0.480.21-0.35PostE6 0.44-0.40.1.00.1.000.95-0.020.75-0.13PostE8 0.03*0.760.420.480.100.810.04*-0.580.04*-0.56PostE10 0.300.520.100.900.190.810.23-0.390.63-0.16PostE12
  • Correlation between intra operative and post operative ECAP thresholds with postoperative performance in CI24 Device LANGUAGE AGE Aided WDS eout VC Aided WDS eVCAided SDTAided CI response CI24 P-valuerP-valuerP-valuerP-valuerP-valuer 0.100.400.200.690.720.220.06-0.400.09-0.36IntraE5 0.110.400.170.720.660.270.03*-0.450.05-0.42IntraE10 0.120.390.49-0.350.36-0.530.620.110.98-0.01IntraE15 0.130.380.540.371.000.000.08-0.380.10-0.36IntraE20 0.300.270.93-0.110.98-0.030.32-0.240.42-0.20PostE5 0.380.230.83-0.170.95-0.050.45-0.180.54-0.15PostE10 0.350.250.39-0.500.20-0.690.37-0.200.27-0.25PostE15 0.170.360.34-0.550.08-0.830.08-0.390.06-0.41PostE20
  • CONCLUSION  This study showed increase in electrode impedance values measured postoperatively than that measured intraoperatively with highest values at time of initial stimulation, and high impedance values at basal electrodes.  Total incidence of devices with at least 1 electrode with abnormal impedance (OC/SC) was 9% in the intra operative measurements which remained the same post operatively.  Successfully recorded ECAP per electrode is higher intra operatively than that recorded post operatively.
  • CONCLUSION, cont.  ECAP thresholds showed non significant decrease postoperatively compared with that measured intraoperatively, with high thresholds of electrodes at basal ends of cochlea and low at apical ends.  There was no correlation between intraoperative or post operative ECAP measurements with the patient's post operative performance
  • RECOMMENDATIONS  Measuring the ECAP thresholds at the same visit of programming the speech processor especially for children and measuring it several times with in the first year of implant use.  To determine the most appropriate time to obtain baseline electrophysiologic measures to which long-term measures may be compared, it is best to make base-line measures at a time when ECAP thresholds stabilize.  More research is needed to verify the differences between children and adults, regarding measured Electrode Impedance and ECAP.
  • RECOMMENDATIONS, cont.  New research studies are required for further understanding about the characteristics and prevalence of responses obtained by Neural Telemetry, as well as to determine their capacity to predict behavior thresholds.  New research studies are required to explore the ECAP telemetry to find peripheral constraints limiting cochlear implant performance.
  • Thank you