10.14639/0392-100X-N1557
Objectives. To investigate the long-term effects of cochlear implants as a treatment for patients with severe to profound neurosensory loss associated with severe tinnitus.Methods. Prospective study in 17 adult patients with severe to profound sensorineural hearing loss associated with severe tinnitus, indicated with a Tinnitus Handicap Inventory (THI) score ≥ 58%, and hyperacusis. Measures were made on hearing, tinnitus, hyperacusis and quality of life up to 5 years after activation of the sound processor of the cochlear implant. It was evaluated by using the disyllabic test, THI, visual analogue scale and Glasgow Benefit Inventory questionnaire.Results. 60 months after cochlear implantation, improvements in loudness and discomfort of tinnitus, speech discrimination and hyperacusis were observed. Subjects perceive an important subjective benefit upon receiving the cochlear implant.Conclusions. Cochlear implants can be used as treatment for patients with severe to profound sensorineural hearing loss associated with severe tinnitus and hyperacusis with longterm benefits on quality of life and lasting relief of tinnitus.
text/xml
1827-675X
1557
en
Angel Ramos Macías
http://creativecommons.org/licenses/by-nc-nd/4.0
ACTA Otorhinolaryngologica Italica
hearing loss
Tinnitus suppression with electrical stimulation in adults: long-term follow-up
Text.Serial.Journal
https://www.actaitalica.it/
42
Audiology
2022-05-16
2021-03-12
2022-05-23
2022-05-23
176-181
1
Angel Ramos Macías
2022/05/16
10.14639/0392-100X-N1557
176
Department of Otolaryngology Head Neck Surgery, Complejo Hospitalario Universitario Insular Materno Infantil de Gran Canaria, Las Palmas, Spain; Department of Otolaryngology, Faculty Medicine, University of Las Palmas de Gran Canaria, Spain
1827-675X
hearing loss
181
Tinnitus suppression with electrical stimulation in adults: long-term follow-up
https://www.actaitalica.it/article/download/1557/800
42
ACTA OTORHINOLARYNGOLOGICA ITALICA 2022;42:176-181; doi: 10.14639/0392-100X-N1557




Audiology


Tinnitus suppression with electrical stimulation
in adults: long-term follow-up
L’annullamento del tinnitus mediante stimolazione elettrica negli adulti:
follow-up a lungo termine
Juan Carlos Falcón González1, Silvia Borkoski Barreiro1, Margarita Torres García de Celis1, Ángel Ramos Macías1,2
1
 Department of Otolaryngology Head Neck Surgery, Complejo Hospitalario Universitario Insular Materno Infantil de Gran Canaria,
Las Palmas, Spain; 2 Department of Otolaryngology, Faculty Medicine, University of Las Palmas de Gran Canaria, Spain


SUMMARY
Objectives. To investigate the long-term effects of cochlear implants as a treatment for pa-
tients with severe to profound neurosensory loss associated with severe tinnitus.
Methods. Prospective study in 17 adult patients with severe to profound sensorineural hear-
ing loss associated with severe tinnitus, indicated with a Tinnitus Handicap Inventory (THI)
score ≥ 58%, and hyperacusis. Measures were made on hearing, tinnitus, hyperacusis and
quality of life up to 5 years after activation of the sound processor of the cochlear implant. It
was evaluated by using the disyllabic test, THI, visual analogue scale and Glasgow Benefit
Inventory questionnaire.
Results. 60 months after cochlear implantation, improvements in loudness and discomfort
of tinnitus, speech discrimination and hyperacusis were observed. Subjects perceive an im-
portant subjective benefit upon receiving the cochlear implant.
Conclusions. Cochlear implants can be used as treatment for patients with severe to pro-
found sensorineural hearing loss associated with severe tinnitus and hyperacusis with long-
term benefits on quality of life and lasting relief of tinnitus.
KEY WORDS: cochlear implant, tinnitus, quality of life, hyperacusis, hearing loss                   Received: March 12, 2021
                                                                                                    Accepted: November 5, 2021
RIASSUNTO
Obiettivi. Mostrare gli effetti a lungo termine degli impianti cocleari nei pazienti con per-       Correspondence
                                                                                                    Silvia Borkoski Barreiro
dita neurosensoriale grave e profonda, associata ad acufene.
                                                                                                    Department of Otolaryngology Head Neck Surgery,
Metodi. Studio prospettico su 17 pazienti adulti con ipoacusia neurosensoriale da grave             Complejo Hospitalario Universitario Insular Mater-
a profonda associata ad acufene grave, con un punteggio Tinnitus Handicap Inventory                 no Infantil de Gran Canaria, Av. Marítima del Sur
(THI) ≥ 58% e iperacusia. Abbiamo analizzato udito, tinnito, iperacusia e qualità della vita        s/n, 35016 Las Palmas de Gran Canaria, Spain
durante un follow-up di 5 anni dopo l’attivazione dell’elaboratore del suono dell’impianto          Tel. +34 928441801. Fax +34 928444068
cocleare. Mediante test disillabico, abbiam valutato il THI, la scala analogica visiva e il         E-mail: silviaborkoski@hotmail.com
questionario Glasgow Benefit Inventory.
Risultati. 60 mesi dopo l’impianto cocleare, si osservano miglioramenti nell’intensità e              How to cite this article: Falcón González JC,
grado di discomfort da acufene, nella discriminazione del linguaggio ed iperacusia. I sog-            Borkoski Barreiro S, Torres García de Celis
getti percepiscono un importante beneficio soggettivo post impianto cocleare.                         M, et al. Tinnitus suppression with electrical
Conclusioni. gli impianti cocleari possono essere utilizzati come trattamento per i pazienti          stimulation in adults: long-term follow-up. Acta
con ipoacusia neurosensoriale da grave a profonda associata ad acufene grave e ipera-                 Otorhinolaryngol Ital 2022;42:176-181. https://
cusia, poiché si osservano benefici a lungo termine sulla qualità della vita e un sollievo            doi.org/10.14639/0392-100X-N1557
duraturo sull’acufene.
                                                                                                    © Società Italiana di Otorinolaringoiatria
PAROLE CHIAVE: impianto cocleare, tinnito, qualità della vita, iperacusia, perdita                  e Chirurgia Cervico-Facciale
dell’udito
                                                                                                                   OPEN ACCESS

                                                                                                    This is an open access article distributed in accordance with
Introduction                                                                                        the CC-BY-NC-ND (Creative Commons Attribution-Non-
                                                                                                    Commercial-NoDerivatives 4.0 International) license. The
Tinnitus is defined as sound perception without any external sound source.                          article can be used by giving appropriate credit and mentio-
                                                                                                    ning the license, but only for non-commercial purposes and
The physiopathology of tinnitus is not completely understood 1. The different                       only in the original version. For further information: https://
theories assume that a peripheric lesion in the cochlear hair cells induce a cen-                   creativecommons.org/licenses/by-nc-nd/4.0/deed.en




176
                                                                                  Electrical tinnitus suppression with long-term follow-up




tral nervous system maladaptive or suboptimal plasticity,         (grade 1), mild disability 18-36% (grade 2), moderate dis-
which in turn induces reorganisation and hyperactivity of         ability 38-56% (grade 3) and severe disability 58-100%
non-auditory and central auditory structures 1,2.                 (grade 4) 12,13.
Severe tinnitus can have debilitating psychosocial conse-         Tinnitus sonority/discomfort was assessed using a Visual
quences and cause psychiatric disorders in 1-3% of the gen-       Analogic Scale (VAS) ranging from 0 to 10 14.
eral population 3. Disabling tinnitus in a patient with unilat-   Hearing thresholds were evaluated by pure-tone audiom-
eral hearing loss can affect speech discrimination in noise,      etry; speech discrimination was evaluated by using the two-
while a cochlear implant (that “activates” the deaf ear can       syllables words test in quiet (S0) and the Protocol for the
improve tinnitus and speech discrimination in noise 4. Tin-       Assessment of hearing in Spanish language, and hypera-
nitus suppression occurs mainly during the active use of a        cusis was evaluated by using the Sound Hypersensitivity
cochlear implant and is stable over time 5-7. Some cochlear       Questionnaire (SHQ), known in Spain as ‘Test de Hiper-
implant holders experience a residual inhibition of tinnitus      sensibilidad al Sonido” 15,16.
when the implant is switched off, and these periods can ex-       The effect of the intervention on the quality of life of the
tend during the night; they thus experience complete relief       patient was assessed using the Glasgow Benefit Inventory
of tinnitus 8. The suppressive effects of concomitant tinnitus    Questionnaire (GBI), developed and validated by Robinson
in cochlear implant holders can be explained by the effects       et al. in 1996 17.
of masking/blinding and the plastic changes in the hearing        All surgeries were performed by the same surgical team/
system by enhancement of peripheric hearing input 9.              staff. The advanced combination encoders (ACE) codifi-
The objective of this study is to evaluate the long-term ef-      cation strategy was applied to programme the speech pro-
fects of cochlear implants as treatment for patients with se-     cessor using versions 5.0 and 6.0 of the Software Custom
vere to profound neurosensory loss associated with severe         Sound, and frequency assignation by channel method was
tinnitus.                                                         applied 18,19.

Materials and methods                                             Statistical analysis
                                                                  Exploratory and descriptive analysis was performed.
A repeated-measurements, intrasubject, prospective and            Distribution equality analysis was done by using analysis
5-year follow-up study is presented. Patients to be included      of variance (ANOVA) or the Kruskal-Wallis test, depend-
had to fulfil the following criteria: over 18 years of age,       ing on the data characteristics.
having an ear to be implanted fulfilling cochlear implanta-       Correlation analysis was performed among the indicators
tion criteria 10, presenting tinnitus with disability indicated   of communication difficulty level of the subscales and the
by a Tinnitus Handicap Inventory (THI) 11 score ≥ 58%,            quality of life.
showing normal hearing or mild/moderate hearing loss in           The statistical package SPSS (Statistical Package for the
the contralateral ear and failure of conventional treatments      Social Sciences), version 25.0 for Windows 10 Profes-
for tinnitus during ≥ 6 months. Tinnitus treatments were          sional, was used. A p-value α < 0.05 was considered to be
Tinnitus Retraining Therapy (TRT) and cognitive behav-            statistically significant.
ioural therapy.
Exclusion criteria included central-origin tinnitus, pulsa-
tile tinnitus, paroxysmal tinnitus, somatosensorial tinnitus,
                                                                  Results
headache/migraine-related tinnitus, vertigo-related tinni-        A total of 17 patients, 10 men and 7 women, presenting se-
tus, posttraumatic tinnitus and psychological/psychiatric         vere to profound hearing loss in the ear to be implanted were
disorders associated with tinnitus verified by a psycholo-        included. With respect to the contralateral ear, 15 patients
gist/psychiatrist.                                                showed normal hearing and 2 showed mild hearing loss.
Before surgery, assessment of tinnitus, including medical         After 5-year follow-up of the contralateral ear, 11 patients
history, of hearing and quality of life was performed. Tin-       still showed normal hearing, 5 patient showed mild hearing
nitus was assessed within the visit for cochlear implant ac-      loss and 1 patient showed moderate hearing loss.
tivation. Tinnitus and hearing assessments were repeated in       The aetiology of hearing loss was unknown in 58.82% of
the scheduled visits of the study: 1, 6 and every 12 months       subjects (10 patients), otosclerosis in 29.42% of subjects
until 5 years after the first activation.                         (5 patients) and meningitis in 11.76% of subjects (2 pa-
The evaluation of disability provoked by tinnitus was per-        tients).
formed using the Spanish version of THI; including dis-           The onset of the hearing loss was sudden in most patients
ability categories for THI score: without handicap 0-16%          (13/17 = 76.47%) and progressive in 4 patients (23.53%).



                                                                                                                                    177
J.C. Falcón González et al.




The time to hearing loss in the implanted ear was generally
short (< 2 years in 13/17 = 76.47%), but was > 10 years in
4 patients (23.53%).
All patients received cochlear implants: Systems Nucle-
us® - Cochlear.
Figure 1 shows the THI evolution of patients with scores
obtained in the presurgical visit, during activation of the
speech processor, and at 1, 6, 12, 24, 36, 48 and 60 months
after first activation of the speech processor. At 60 months
post-activation, scores were significantly lower than those
at pre-surgery (p < 0.005).
The SHQ pre-surgery scores were high, indicating ì impor-
tant interference of tinnitus/hyperacusis on hearing; ‘very
severely incapacitating’ (SHQ score: 26-45) in 9 patients,
‘severely incapacitating’ (SHQ score: 18-25) in 5 patients
and ‘moderately incapacitating’ (SHQ score: 11-17) in
3 patients. Clinically, SHQ scores decreased from very se-
                                                                             Figure 2. VAS changes in presurgical and processor tinnitus perception be-
vere to mild-moderate in all patients after 5 years.                         fore its implantation and up to 60 months post-implantation.
The VAS results obtained during the pre-surgery visit,
when the speech processor was activated and at 1, 6, 12,
24, 36, 48 and 60 months after the first activation are shown
in Figure 2.
Two-syllable word recognition results per patient obtained
at 12, 24, 36, 48 and 60 months after speech processor first
activation are shown in Figure 3.
Table I shows the results of the THI and VAS for individual pa-
tients obtained during the pre-operative visit and over 5-year
follow-up with the cochlear implant (CI) switched on and off.
Figures 4 and 5 show the overall score per patient in sub-
scales of the quality questionnaire GBI.




                                                                             Figure 3. Percentage of disyllabic word recognition. Dis: disyllabic; m: months.


                                                                             Scores of the General (health state) Subscale (Fig. 4) and
                                                                             Physical Health Subscale increases, and significant differ-
                                                                             ences were observed when comparing pre-surgery scores
                                                                             and their evolution until the 60th post-CI month (P val-
                                                                             ue < 0.001).
                                                                             With respect to the Social Support Subscale (Fig. 5), the
                                                                             scores obtained before CI and throughout 60 months re-
                                                                             mained stable, and no significant differences were observed
Figure 1. THI evolution since before speech processor activation up to the
60th month post implantation.                                                (P value > 0.05).



178
                                                                                               Electrical tinnitus suppression with long-term follow-up




Table I. Results of THI and VAS during 5-year follow-up.
 Subject                            Test                   Pre CI   Activation   1 m.   6 m.     12 m.       24 m.      36 m.      48 m.      60 m.
 1                                   THI                    78          62        38     58       68          68         38         42         38
                             VAS processor off               8           8         8      9       10          10          8          8          8
                             VAS processor on                            5         4      4        8           8          4          4          4
 2                                   THI                    78          66        16     14       14          16         14         14          8
                             VAS processor off              10          10         7      7        7           7          5          5          5
                             VAS processor on                            2         0      0        0           0          0          0          0
 3                                   THI                    100         98        74     98       80          80         80         74         74
                             VAS processor off              10          10        10     10       10          10         10         10         10
                             VAS processor on                           10         8     10        4           4          4          4          4
 4                                   THI                    88          74        88     42       42          42         42         38         38
                             VAS processor off              10          10        10      3        5           5          5          5          5
                             VAS processor on                            8         8      3        4           4          4          0          0
 5                                   THI                    74          86        88     68       16          16         16         14         16
                             VAS processor off              10          10        10     10        8           8          8          5          5
                             VAS processor on                            9         9      9        3           3          3          0          0
 6                                   THI                    78          62        38     58       68          68         38         42         38
                             VAS processor off               8           8         8      9       10          10          8          8          8
                             VAS processor on                            5         4      4        8           8          4          4          4
 7                                   THI                    78          66        16     14       14          16         14         14          8
                             VAS processor off              10          10         7      7        7           7          5          5          5
                             VAS processor on                            2         0      0        0           0          0          0          0
 8                                   THI                    100         98        74     98       80          80         80         74         74
                             VAS processor off              10          10        10     10       10          10         10         10         10
                             VAS processor on                           10         8     10        4           4          4          4          4
 9                                   THI                    88          74        88     42       42          42         42         38         38
                             VAS processor off              10          10        10      3        5           5          5          5          5
                             VAS processor on                            8         8      3        4           4          4          0          0
 10                                  THI                    74          86        88     68       16          16         16         14         16
                             VAS processor off              10          10        10     10        8           8          8          5          5
                             VAS processor on                            9         9      9        3           3          3          0          0
 11                                  THI                    78          62        38     58       68          68         38         42         38
                             VAS processor off               8           8         8      9       10          10          8          8          8
                             VAS processor on                            5         4      4        8           8          4          4          4
 12                                  THI                    78          66        16     14       14          16         14         14          8
                             VAS processor off              10          10         7      7        7           7          5          5          5
                             VAS processor on                            2         0      0        0           0          0          0          0
 13                                  THI                    100         98        74     98       80          80         80         74         74
                             VAS processor off              10          10        10     10       10          10         10         10         10
                             VAS processor on                           10         8     10        4           4          4          4          4
 14                                  THI                    88          74        88     42       42          42         42         38         38
                             VAS processor off              10          10        10      3        5           5          5          5          5
                             VAS processor on                            8         8      3        4           4          4          0          0
 15                                  THI                    74          86        88     68       16          16         16         14         16
                             VAS processor off              10          10        10     10        8           8          8          5          5
                             VAS processor on                            9         9      9        3           3          3          0          0
 16                                  THI                    78          62        38     58       68          68         38         42         38
                             VAS processor off               8           8         8      9       10          10          8          8          8
                             VAS processor on                            5         4      4        8           8          4          4          4
 17                                  THI                    78          66        16     14       14          16         14         14          8
                             VAS processor off              10          10         7      7        7           7          5          5          5
                             VAS processor on                            2         0      0        0           0          0          0          0
CI: Cochlear Implantation; m: months.


                                                                                                                                                 179
J.C. Falcón González et al.




                                                                               affects the perception of tinnitus. Some patients experience
                                                                               a significant decrease in tinnitus just after first activation of
                                                                               their CI, which suggests an effect of tinnitus masking/blind-
                                                                               ing due to the increase in auditory information.
                                                                               Currently, many studies have established the impact of
                                                                               cochlear implantation on the decrease of tinnitus 6,8,21-24.
                                                                               The results in our patients show a significant and clinical
                                                                               decrease in tinnitus disability and perception in the long-
                                                                               term, similar to those described in other studies 23,25,26.
                                                                               As described by Mertens et al., a significant decrease in
                                                                               tinnitus sonority score was seen in the long-term with the
                                                                               implant switched off, although this effect was lower than
                                                                               that observed when the implant was switched on 23.
                                                                               Patients with hyperacusis show a lower capacity to ignore
                                                                               tinnitus, and the impact of associated depression and qual-
                                                                               ity of life is higher than that observed in patients with tin-
                                                                               nitus without hyperacusis. These patients have a significant
Figure 4. General Score of the GBI. m: months; pos: post; CI Cochlear Im-      need for treatment of their incapacitating tinnitus when it
plantation.
                                                                               is accompanied by hyperacusis. As described by Mertens
                                                                               et al. 23, a significant decrease from very severe to mild-
                                                                               moderate in all patients in the long term in the SHQ test
                                                                               scores was observed. In our patients, CI surgery resulted in
                                                                               a positive effect on sound intolerance.
                                                                               The results of this study show, in subscales General Score
                                                                               and Physical Health Score of the quality questionnaire
                                                                               GBI, a significant subjective benefit when comparing pre-
                                                                               surgery scores and their changes up to the 60th post-CI
                                                                               month; similar results are seen in other published series, in
                                                                               which a significant benefit in quality of life is observed in
                                                                               patients with tinnitus treated with a CI 24-26.
                                                                               All patients in our study presented complete insertion of
                                                                               the electrodes, and we believe this is necessary to achieve
                                                                               good CI performance and suppression of tinnitus.
                                                                               In view of the above, cochlear implants should be con-
                                                                               sidered as a valid treatment option for this population, al-
                                                                               though careful selection of the patient must be performed.

Figure 5. Social support score of the GBI. m: months; pos: post; CI Cochlear   Conclusions
Implantation
                                                                               Cochlear implant can be successfully used as treatment
                                                                               for patients with severe to profound sensorineural hearing
Discussion                                                                     loss associated with disabling tinnitus and hyperacusis with
                                                                               lasting relief of tinnitus and hyperacusis, and benefits in
The study by Van de Heyning et al. was the first to demon-                     hearing and quality of life in the long-term.
strate a significant and consistent decrease in tinnitus volume
after cochlear implantation and, consequently, suggested the                   Conflict of interest statement
use of cochlear implant as a new treatment for tinnitus 20.                    The authors declare no conflict of interest.
The physio-pathological mechanisms of tinnitus suppression
after cochlear implantation are not yet completely under-                      Funding
stood. It is surmised that electrical stimulation through the                  This research did not receive any specific grant from funding
CI induces cortex reorganisation by neuroplasticity, which                     agencies in the public, commercial, or not-for-profit sectors.



180
                                                                                                    Electrical tinnitus suppression with long-term follow-up




Authors’ contributions                                                         11
                                                                                    Herráiz C, Hernández Calvín J, Plaza G, et al. Evaluación de la inca-
FGJC: data acquisition, cochlear implant fitting program-                           pacidad en pacientes con acúfenos. [Handicap evaluation in tinnitus
                                                                                    patients]. Acta Otorrinolaringol Esp 2001;52:534-538. https://doi.
ming, and statistics study. BBS: data acquisition and manu-                         org/10.1016/s0001-6519(01)78247-7
script writing. TGdCM: literature review and audiological                      12
                                                                                    Newman CW, Sandridge SA, Jacobson GP. Psychometric adequacy of
assessments. ARM: literature review and writing of the                              the Tinnitus Handicap Inventory (THI) for evaluating treatment out-
manuscript. All authors contributed to the article and ap-                          come. J Am Acad Audiol 1998;9:153-160.
proved the submitted version.                                                  13
                                                                                    McCombe A, Baguley D, Coles R, et al. Guidelines for the grading
                                                                                    of tinnitus severity: the results of a working group commissioned by
                                                                                    the British Association of Otolaryngologists, Head and Neck Sur-
Ethical consideration                                                               geons, 1999. Clin Otolaryngol Allied Sci 2001;26:388-393. https://
This study was approved by the Institutional Ethics Com-                            doi.org/10.1046/j.1365-2273.2001.00490.x
mittee of the Complejo Hospitalario Universitario Insular                      14
                                                                                    Miller MD, Ferris DG. Measurement of subjective phenomena in
Materno Infantil de Gran Canaria (approval number/proto-                            primary care research: the Visual Analogue Scale. Fam Pract Res J
                                                                                    1993;13:15-24.
col number 54 CE certificate).
                                                                               15
                                                                                    Huarte A, Molina M, Manrique M, et al. Protocolo para la valoración
Researchers informed patients about the risks and benefits
                                                                                    de la audición y el lenguaje, en lengua española, en un programa de
of participating in this study, who gave their informed con-                        implantes cocleares. Acta Otorrinolaringol Esp 1996;47:1-14.
sent prior to study initiation.                                                16
                                                                                    Herráiz C, de los Santos G, Diges I, et al. Evaluación de la hipera-
The research was conducted ethically, with all study pro-                           cusia: test de hipersensibilidad al sonido [Assessment of hyperacu-
cedures being performed in accordance with the require-                             sis: the self-rating questionnaire on hypersensitivity to sound]. Acta
                                                                                    Otorrinolaringol Esp 2006;57:303-306. https://doi.org/ 10.1016/
ments of the World Medical Association’s Declaration of                             s0001-6519(06)78716-7
Helsinki.                                                                      17
                                                                                    Robinson K, Gatehouse S, Browning GG. Measuring patient benefit
Written informed consent was obtained from each partici-                            from otorhinolaryngological surgery and therapy. Ann Otol Rhino
pant/patient for study participation and data publication.                          Laryngol 1996;6:415-422.
                                                                               18
                                                                                    Falcón J, Borkoski S, Limiñana J, et al. Recognition of music and
                                                                                    melody in patients with cochlear implants, using a new program-
References                                                                          ming approach for frequency assignment. Acta Otorrinolaringol Esp
1
     Peter N, Kleinjung T. Neuromodulation for tinnitus treatment: an               2014;65:289-296. https://doi.org/10.1016/j.otorri.2014.02.005
     overview of invasive and non-invasive techniques. J Zhejiang Univ         19
                                                                                    Falcón J, Borkoski S, Ramos A, et al. Improvement of speech percep-
     Sci B 2019;20:116-130. https://doi.org/10.1631/jzus.B1700117                   tion in noise and quiet using a customised Frequency-Allocation Pro-
2
     Vanneste S, De Ridder D. The auditory and non-auditory brain areas             gramming (FAP) method. Acta Otorhinolaryngol Ital 2019;39:178-
     involved in tinnitus: an emergent property of multiple parallel over-          185. https://doi.org/10.14639/0392-100X-2013
     lapping subnetworks. Front Syst Neurosci 2012;8;6:31. https://doi.        20
                                                                                    Van de Heyning P, Vermeire K, Diebl M, et al. Incapacitating uni-
     org/10.3389/fnsys.2012.00031                                                   lateral tinnitus in single-sided deafness treated by cochlear implan-
3
     Dobie RA. Depression and tinnitus. Otolaryngol Clin North Am                   tation. Ann Otol Rhinol Laryngol 2008;117:645-652. https://doi.
     2003;36:383-388. https://doi.org/10.1016/s0030-6665(02)00168-8                 org/10.1177/000348940811700903
4
     Mertens G, Punte AK,, De Ridder D, et al. Tinnitus in a single-sided      21
                                                                                    Zenner HP, Delb W, Kröner-Herwig B, et al. A multidisciplinary sys-
     deaf ear reduces speech reception in the nontinnitus ear. Otol Neurotol        tematic review of the treatment for chronic idiopathic tinnitus. Eur
     2013;34:662-666. https://doi.org/10.1097/MAO.0b013e31828779f0                  Arch Otorhinolaryngol 2017;274:2079-2091. https://doi.org/10.1007/
5
     Punte AK, Vermeire K, Hofkens A, et al. Cochlear implantation as               s00405-016-4401-y
     a durable tinnitus treatment in single sided deafness. Cochlear Im-       22
                                                                                    Knopke S, Szczepek AJ, Häussler SM, et al. Cochlear implantation
     plants Int 2011;12(Suppl 1):S26-S29. https://doi.org/10.1179/14670
                                                                                    of bilaterally deafened patients with tinnitus induces sustained de-
     1011X13001035752336
                                                                                    crease of tinnitus-related distress. Front Neurol 2017;8:158. https://
6
     Ramos Macías A, Falcón González JC, Manrique M, et al. Cochlear                doi.org/10.3389/fneur.2017.00158
     implants as a treatment option for unilateral hearing loss, severe tin-
     nitus and hyperacusis. Audiol Neurootol 2015;20:60-66. https://doi.
                                                                               23
                                                                                    Mertens G, De Bodt M, Van de Heyning P. Cochlear implantation as
     org/10.1159/000380750                                                          a long-term treatment for ipsilateral incapacitating tinnitus in sub-
                                                                                    jects with unilateral hearing loss up to 10 years. Hear Res 2016;331:1-
7
     Pierzycki RH, Corner C, Fielden CA, et al. Effects of tinnitus on coch-
                                                                                    6. https://doi.org/10.1016/j.heares.2015.09.016
     lear implant programming. Trends Hear 2019;23:2331216519836624.
     https://doi.org/10.1177/2331216519836624
                                                                               24
                                                                                    Ramos A, Falcón JC, Manrique M, et al. One-year results for pa-
8
     Borges ALF, Duarte PLES, Almeida RBS, et al. Cochlear implant and              tients with unilateral hearing loss and accompanying severe tin-
     tinnitus-a meta-analysis. Braz J Otorhinolaryngol 2021;87:353-365.             nitus and hyperacusis treated with a cochlear implant. Audiol Neu-
     https://doi.org/10.1016/j.bjorl.2020.11.006                                    rootol 2018;23:8-19. https://doi.org/10.1159/000488755
9
     Eggermont JJ. Tinnitus and neural plasticity (Tonndorf lecture at XIth
                                                                               25
                                                                                    Arts R, George E, Janssen M, et al. Tinnitus suppression by intrac-
     International Tinnitus Seminar, Berlin, 2014). Hear Res 2015;319:1-            ochlear electrical stimulation in single sided deafness a prospective
     11. https://doi.org/10.1016/j.heares.2014.10.002                               clinical trial: follow-up. PLoS One 2016;11:e0153131.
10
     Manrique M, Ramos A, de Paula Vernetta C, et al. Guideline on coch-       26
                                                                                    Holder JT, O’Connell B, Hedley-Williams A, et al. Cochlear implanta-
     lear implants. Acta Otorrinolaringol Esp 2019;70:47-54. https//doi.            tion for single sided deafness and tinnitus suppression. Am J Otolaryn-
     org/10.1016/j.otorri.2017.10.007                                               gol 2017;38:226-229. https://doi.org/10.1016/j.amjoto.2017.01.020




                                                                                                                                                      181
