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Electroacoustic Stimulation with Cochlear Implants for Deafness Treatment
João Paulo Peral Valente1, Luciane Calonga2, Alexandre Caixeta Guimarães1, Walter Adriano Bianchini1 , Jorge Rizzato Paschoal1 and Guilherme Machado de Carvalho1*
1Department of ENT, Campinas University, South America
2Department of Audiologist, Cochlear Implant Specialist, South America
Submission: July 09, 2016; Published: August 05, 2016
*Corresponding author: Guilherme Machado de Carvalho, Head & Neck Surgery Department, UNICAMP, PO Box 6111, Postal Code: 13081-970, São Paulo, Brazil, South America.
How to cite this article: Guilherme M dC, João P PV, Luciane C, Alexandre CG, Walter A B, et al. Electroacoustic Stimulation with Cochlear Implants for Deafness Treatment. Glob J Oto. 2016; 1(5): 555572. DOI: 10.19080/GJO.2016.01.555572
Background: Cochlear implant is an electronic hearing aid surgically inserted into the inner ear that, unlike a conventional hearing aid, picks up sound waves and transforms it into an electrical impulse that directly stimulates the cochlear nerve.
Objective: This study aims to describe the profile and outcomes of patients submitted to hybrid cochlear implant in the in a tertiary hospital in the last three years.
Methods: It was conducted a clinical study including 8 patients implanted with the brand MED-EL FLEX EAS in a tertiary hospital in the last three years.
Results: It was observed an improvement in all tonal thresholds after the activation of the cochlear implant.
Conclusion: The hybrid cochlear implant was successful procedure, with an improvement of tonal thresholds after the activation of cochlear implants..
Cochlear implant is an electronic hearing aid surgically inserted into the inner ear that, unlike a conventional hearing aid, picks up sound waves and transforms it into an electrical impulse that directly stimulates the cochlear nerve. The development of multichannel cochlear implants, new speech processing strategies and more modern processors enabled gradually better results. In 1995, most of the implanted patients already reached results above 80% correct sentences in speech perception tests [1,2]. With the improvement of the cochlear implant performance, studies began to be developed to carry out cochlear implant in patients with residual hearing, which were not good fit with hearing aids.
New types of electrodes and changes in surgical technique have been developed in order to preserve the auditory trace these patients and promote rehabilitation by means of electrical stimulation combined with the acoustic stimulation (soft surgery) [3-7]. The electro-acoustic stimulation (EAS) of hearing aims to combine the amplification of residual hearing of the patient by conventional hearing aids, with electrical stimulation of the cochlea performed by the cochlear implant . This is the principle of hybrid cochlear implants. This study aims to describe the profile and outcomes of patients submitted to hybrid cochlear implant in a tertiary hospital in the last three years.
It was conducted a clinical study including 8 patients implanted with the brand MED-EL FLEX EAS in a tertiary hospital in the last three years. Were admitted to the study all patients in the last three years whose implant was done with full insertion of the electrode bundle and consented to participate in the study through the Term of Consent. All patients used the internal component SONATA TM model and have been adapted by Maestro System TM software. Patients who had postoperative electro stimulation used speech processor DUET 2 Tim. The group had purely electrical stimulation postoperative differed only in the speech processor, having been used in such cases the OPUS 2 Tim. Patients with incomplete data, which did not meet the inclusion criteria or who would not be subject to such assessment were excluded from this Protocol.
Audiological tests were performed including impedanciometry,
speech and pure tone audiometry. The tests were performed
using an audiometer AC30-SD25, calibrated according to ISO 389
standards / 64. The OAEs distortion products were performed at
frequencies 700 to 8000 Hz with stimulus at 65-55 dB SPL, with
a frequency ratio of 1.22. OEA was considered present when the
signal/noise ratio was greater than 6 dB, and with reproducibility
greater than or equal to 70%. The tests from the ABR and CM
were performed with insert earphones. Stimulus of 100 dB HL
was used for the ABR covered with frequencies between 250 and
8.000 Hz, with duration of 100 microseconds, and condensed
and rarefied polarities. The abnormality of ABR was defined as
absence of wave formation or severe changes in morphology of
the same with up to 100 dB HL stimulus.
The CM was evaluated in tests from the ABR, with the feature
of inverting the polarity (condensed and rarefied). When CM was
positive with stimuli of 100 dB HL electrophysiological threshold,
in decreasing order was researched. For ABR, which were repeated
at least two times, the device AT-235 (Interacoustics) was used.
Hearing loss impairment was classified through audiometry
stratification in mild, moderate, severe / severe or profound
hearing loss .
Speech perception tests: During preoperative evaluation, all
subjects underwent to a speech perception test on the same day
of their surgery. The speech perception test is based on several
studies in English language, adapted and developed for Portuguese
language by Bevilacqua et al. . Patients performed the tests
with hearing aids, in a quiet and peaceful place (best aided condition).
Postoperatively, all subjects repeated the speech perception
test at least one year experience with cochlear implant. The
tests were performed using the cochlear implant (CI). The same
audiologist performed all tests (pre-and postoperative).
Subjective evaluations: When the patients did their
postoperative speech tests it were asked to rate the quality of
their experience with CI compared to last year on a Likert scale
ranging from 0 to 10, similar to the visual analog scale. A score
of 0 indicates that user intervention regretted not recommend to
others, and felt he / she had been better in the past, with their
hearing aids. A score of 10 indicates that the user was completely
satisfied with the work and highly recommended.
The data were analyzed using descriptive analysis, with
production of means, medians, standard deviation tabs. Chi-
Square was used to compare the groups of our sample. Because
of the small size of some of the variables analyzed Fisher’s Exact
test was also used to check the correlation between the groups.
The confidence Interval was of 95%, and p-value <0.05 was
The institutional review board approved this study and
all subjects gave written informed consent. The survey was
conducted considering ethical, and was approved by the Ethics
Committee under protocol number 24802914.8.0000.5404.
The hybrid cochlear implants were performed in 8 patients in
these periods. The evaluated aspects are described in (Table 1). In
(Figure 1) can be seen the average of pure tone thresholds in the
preoperative, postoperative and after activation of the cochlear
The EAS of hearing aims to combine the amplification of
residual hearing of the patient by conventional hearing aids, with
electrical stimulation of the cochlea performed by the cochlear
implant. It is an excellent option for people with residual hearing
in low frequencies (preserved below 1 kHz) but not at high
frequencies and with insufficient benefit with hearing aids .
Typically, these individuals are able to detect all the vowels, but
probably few or no consonants. The low frequencies also provide
additional information for speech perception, speech production
and perception of environment sounds. This preservation of
residual hearing of low frequency despite the insertion of an electrode has become the cornerstone for the consolidation of this
concept [6,7] (Table 2).
With the prospect of the combined EAS cochlear implant
should not compromise the residual hearing. New prototype
electrodes are therefore currently under development to ensure
the preservation of hearing. Surgical measures to avoid trauma
to the basal turn are of great importance in preserving residual
hearing . There are indications that the new prototype of the
Med-El Flex electrode has good mechanical properties for the
secure deployment and atraumatic: is highly flexible, especially
on the edge of the area, producing no substantial trauma to the
cochlea structures and is inserted using an appropriate surgical
technique atraumatic . The lack of anatomical trauma to the
cochlear structures is necessary for the preservation of residual
hearing of low frequency.
Several studies have demonstrated the superiority of bimodal
stimulation EAS for patients with residual hearing who had
preserved hearing about any other modality. These advantages
were especially observed with increasing speech recognition,
better perception in noisy environments, subjective improvements
in sound quality when listening to music, and other situations
[6,7,12-14]. Another multi centric clinical study demonstrated
the effect of EAS in individuals with residual hearing of low
frequency, both in speech perception and subjective quality [6,7].
The subjects were evaluated based on a series of audiological
tests, and through a subjective questionnaire to assess the benefit
of the hearing aid. Each subject underwent attempted hearing
preservation cochlear using MED-EL electrode C40. Residual
hearing ipsilateral and discrimination skills were evaluated at
set intervals up to 12 months after the EAS. All subjects had a
statistically significant benefit in all three tests speech perception
over time. These significant benefits were also reflected in the
subjective results of benefit by using the questionnaire. The
worsening at tonal thresholds after the surgery is justified by the surgical trauma, but it was observed an improvement in all
tonal thresholds after the activation of the cochlear implant. The
hybrid cochlear implant was a successful procedure, with an
improvement of tonal thresholds after the activation of cochlear
The soft surgery was a successful procedure considering
the improvement and preservation of tonal thresholds after the
activation of cochlear implants, with no complications regarding
the studied patients.