Week 10 EAS Flashcards
EAS approval dates for each manufacturer
- cochlear= march 2014
- med-el= September 2016
- AB= not approved, but can use it with Naida technology because they did not come up with a new internal device, just an external device that had EAS capabilities
EAS electrodes size
- shorter electrode
- –lateral wall instead of perimodiolar
- –cochlear hybrid L24= 16 mm lateral wall
- –med-el FLEX 24= 20.9 mm lateral wall
- smaller in diameter and more flexible- designed for lateral wall insertion
- –the major goal is to prevent cochlear damage which is achieved by surgical measures
- traditional electrodes can preserve hearing too (in about 55% of pts)
hearing preservation with CI
- large part is the surgical technique
- –soft surgery is the goal and this would cause less damage
- average threshold shift for 125-750= 14.4-16.4 dB in a study
- AB HiRes 90K had 31.6% preservation
- med-el sonata had 50% preservation
- cochlear advance contour had 59.2% preservation
what happens if there was a failure to preserve hearing with a hybrid array
- re-implantation with a conventional length electrode
- –improved speech scores in noise and quiet after re-implantation
- keep short electrode with adjusting map
- –limited benefit to the patient
- –recommendation of using longer array because of this for the instances when hearing is not preserved so that the array will give some benefit
- —–cochlear used to have 6-10mm electrodes until 2008
current EAS processors
- clinical trial processors
- –cochlear freedom
- –med-el DUET and DUET 2
- approved processors
- –cochlear N6 (CP910/920) and N7(CP1000)
- –Sonnet and Sonnet 2
- other processors
- – AB Naida CI Q90
main difference between EAS with Nucleus 6 and Nucleus 7
nucleus 6 had one receiver option while 7 has a 60, 85, and a 100
how to set the EAS frequency boundary
- Meet approach meaning where acoustic stops is where electric begins
- overlap approach meaning there is a big of a range which gets both electric and acoustic stimuli
- gap approach meaning there is a frequency range between the acoustic and electric ranges which gets no stimulation
- pts preference for meet approach
- no significant difference if you found exactly the last frequency perceived electrically and then do acoustic from there or if you use a best guess of that frequency
- –however the meet approach in general is better in noise and is more natural than other approaches
specifics for where to set up the cutoff frequency for acoustic stimulation
- pts with significant low frequency HL=overlap
- pts with better preserved hearing=meet
- the benefits of acoustic amplification are limited when thresholds exceed 70 dB HL
- –better sentence recognition in noise when electrical cutoff was set to a freq where unaided thresholds exceeded 70 dB HL
clinical protocol for programming EAS devices (8 steps)
1) otoscopic exam
2) eval implant site
3) measure Ac/BC thresholds for implanted ear
- –starting from 125 Hz and every octave and interoctave frequency afterward
- –allow 4 weeks before activation for middle ear effusion to resolve; conductive component may persist
4) possibly eval for the presence of cochlear dead region with the TEN test
5) conduct in situ real-ear probe mic measured to eval output of the acoustic component of the EAS device
- –determine gain and maximum otuput for HA portion
- –find the cut-off freq for acoustic amplifications (<70 d threshold)
6) determine low-freq boundary for the electric signal through “meet” approach
7) measure T-levels for all functional intra-cochlear electrode contacts (inf needed)
8) balance upper-stimulation levels in loudness across the electrode array
EAS Mapping in Cochlear
- after opening the Custom Sound software
- –select the acoustic component
- –view audiogram
- –method and compression
- –earmold
- –frequency boundary
- –9 channels-adjust MPO/gain
- –need real-ear measures like regular HAs
- –then adjust T and C levels, and balance
EAS Mapping with Med-el
- after opening the Maestro software
- –add audiogram
- –select the acoustic component
- –select audiogram and apply first fit
- –activation of processor
- –volume control (default and range)
- –appearance–Target 40, 65, 90 dB
EAS advantages
- improved speech discrimination
- –one year post-op: open-set sentences–71% (pre-op 24%)
- ——poorer EAS benefit associated with poorer pre-op WRS and longer duration of high-freq deafness (>30)
- preserving the LF hearing allows the recipient to utilize the inter-aural timing cues–better speech understanding in noise as a result
- –normal hearing–score 50% with -30dB noise and -15 dB multi-talker babble
- –traditional CI–score 50% with +3 dB noise and +8 dB multi-talker babble
- –hybrid CI–score 50% with -9 dB noise and +8 dB multi-talker babble
- better speech in noise and better localization
- better music perception
predictive variables for post-op outcomes for adults
- there is currently no definitive predictive variables for post-op speech recognition
- –age: provided the pt is medically cleared, no compromised cognitive status or dementia, they can receive substantial benefit regardless of age
- –audiometric thresholds: not a real predictor
- –pre-op speech score is a good predictor
- –duration of deafness is also a good predictor (0-20 years= god, over 20 is worse)
- –integrity of cochlear and neural structures (ANSD/Neuroma) are good predictors
- –etiology is also a good predictor
- —–meningitis= poor
- —–otosclerosis= poor depending on ossification and the number of usable electrodes can decrease over time
- –if the etiology is temporal bone fracture need to make sure there is no damage to the VIII nerve
predictive variables for post-op outcomes for peds
- age at implantation
- –big factor and better if implanted under 13 months than 16-23 months which was still better than 24 months
- —–if implanted under 1 yr then they have similar word learning abilities as children with normal hearing, but still benefit regardless of time
- intervention which is early and consistent gives better oral language outcomes
- pre-implant audio thresholds do dictate success (language access before implant or not)
- etiology
- –meningitis can dictate because of ossification and central effects and damage to neurons
- –syndromes-related deafness can still have positive outcomes and if thy are losing vision want to implant ASAP
- –chromosome related depends on cognitive abilities
- –abnormal cochlear anatomy most benefit but come more than others
- integrity of cochlear and neuro structures plays large role
- –CMV depends on cognitive abilities
- family variables
- additional abilities can benefit but it might not be language benefits
family variable affecting outcomes with CI for peds
- family size (bigger=better)
- intelligence
- SEC
- maternal education
- regularly attending audiology appts
- children wearing CIs regularly
- amount of time spent talking to the child at home
