Electrical Promontory Stimulation Research Articles

Hearing rehabilitation outcomes in cochlear implant recipients with vestibular schwannoma in observation or radiotherapy groups: A systematic review

Objectives: Vestibular schwannomas (VS) are rare benign tumours of the vestibular nerve that cause hearing loss. Management strategies include watchful waiting, radiotherapy or surgical resection. Historically, the presence of retrocochlear disease has been considered to be a contra-indication to cochlear implantation (CI). The aim of this systematic review is to assess hearing rehabilitation outcomes for CI recipients with VS, either sporadic or associated with neurofibromatosis type 2, whose tumours have been managed with either observation or radiotherapy.Methods: PubMed, Embase, and Cochrane Library databases were searched from inception through to November 2018. 50 cases from 12 studies met the inclusion criteria. Patient demographics, VS characteristics, management strategy, pre-CI hearing status, electrical promontory stimulation testing, post-CI hearing status and speech perception scores, functional benefits and follow-up length are reported.Results: Radiotherapy and observation groups had similar patient demographics in terms of age at CI, tumour size and duration of deafness. Following CI, 64% and 60% of patients in the radiotherapy and observation groups achieved open-set speech perception, respectively. Pure tone average thresholds (33 vs. 39 dB) and speech scores were also comparable between both groups.Conclusion: Ipsilateral CI in patients with VS that have not been surgically resected can provide beneficial hearing rehabilitation outcomes.

Impact of cochlear implantation on the management strategy of patients with neurofibromatosis type 2.

To investigate the outcomes of cochlear implantation in patients with neurofibromatosis type 2 (NF2), and to discuss the current management strategy for NF2 patients. The medical records of NF2 patients who received cochlear implants (CI) at our center between 2012 and 2016 were retrospectively reviewed. Pre-operative hearing status, tumor status, treatment of tumors, and auditory outcomes post-implantation were evaluated. Twelve patients were included in the study. Five were implanted with the tumor in situ; two of them received radiotherapy pre-implantation, and three were implanted without any previous treatment. Four patients were implanted simultaneously with tumor removal. Three patients were implanted as second-stage after failed hearing preservation surgery. The mean pure tone audiometry with the implant was 44 dB (range 25-80 dB) and the mean sentence recognition score (SRS) in a quiet environment without lip reading was 63% (range 0-97%). A poorer objective auditory outcome was identified in one patient who showed no response to electrical promontory stimulation (EPS), but the sound perception was still helpful. In total, 11 of 12 (91%) patients were daily users, and the other patient used the implant as a "sleeper" device due to its interference with contralateral hearing provided by a hearing aid. CI is an effective option in auditory rehabilitation and should be considered primarily for NF2 patients with intact cochlear nerve. EPS might be a predictor for cochlear implant performance. Good contralateral hearing may present a barrier to daily use.

Simultaneous Translabyrinthine Tumor Removal and Cochlear Implantation in Vestibular Schwannoma Patients

Refinement of surgical techniques has allowed hearing preservation after tumor resection to be prioritized. Moreover, restoration of hearing after tumor removal can be attempted in patients with bilateral vestibular schwannomas or those with a schwannoma in the only-hearing ear. Cochlear implantation (CI) has emerged as a proper method of acoustic rehabilitation, provided that the cochlear nerve remains intact. Studies of electrical promontory stimulation in patients after vestibular schwannoma resection have demonstrated favorable results. We describe herein two cases of hearing rehabilitation via CI implemented at the time of vestibular schwannoma resection. Tumors were totally removed, and cochlear implant electrodes were successfully inserted in both cases. Also, post operative CI-aided hearing showed improved results.

Cochlear Implantation in Patients With Neurofibromatosis Type 2

To investigate cochlear implant performance outcomes among patients with Neurofibromatosis type 2 (NF2). Retrospective case series, patient questionnaire, and systematic review of the literature. Tertiary academic referral center. All patients with NF2 having an anatomically intact ipsilateral cochlear nerve who underwent cochlear implantation (CI). Cochlear implantation. Postimplantation audiometric performance and patient perceived benefit. Ten patients met study criteria. The median duration of follow-up after CI was 42 months (mean, 46.9 mo; range, 12-97 mo). Five patients received previous microsurgical resection of their ipsilateral vestibular schwannoma, 4 underwent previous stereotactic radiosurgery, and 1 patient had no tumor treatment before CI. Nine subjects achieved sound awareness, 6 attained open-set speech recognition and 7 are daily users. Variables including prolonged auditory deprivation, cochlear ossification, unfavorable electrical promontory stimulation testing, and useful contralateral hearing were associated with poor cochlear implant performance. No statistical associations were found between open-set recognition capacity and previous tumor management strategy, surgical approach, or ipsilateral tumor size. Cochlear implantation is an attractive alternative to auditory brainstem implantation for hearing rehabilitation in patients with NF2. Approximately 70% of patients achieve open-set speech discrimination, many scoring at the ceiling of audiometric testing. Given a favorable risk profile and superior audiometric outcomes, CI should be strongly considered in patients with nonserviceable hearing who have an anatomically intact cochlear nerve, whereas auditory brainstem implantation should be reserved for patients with evidence of cochlear nerve loss. Akin to conventional cochlear implant recipients, prolonged hearing loss, unfavorable electrophysiological testing, and cochlear ossification may predict poor subject performance. Finally, useful hearing in the contralateral ear may present a barrier to daily device use.

Different Clinical Characteristics of Aminoglycoside-Induced Profound Deafness with and without the 1555 A→G Mitochondrial Mutation

Recent genetic studies have shown that hereditary susceptibility to aminoglycoside antibiotics is caused by the 1555 A→G mitochondrial mutation. We found the 1555 mutation in 4 out of 68 postlingual deaf patients who were candidates for cochlear implantation. All 4 patients developed bilateral profound hearing loss following administration of aminoglycosides. The pedigree of the family shows exclusively maternal transmission of hearing impairment in each case. On comparison with neuro-otological findings from aminoglycoside-induced deaf patients without the 1555 mutation, four distinct characteristics were noted: (1) a progressive nature of hearing loss; (2) better residual pure-tone thresholds; (3) lower thresholds for electrical promontory stimulation, and (4) well-preserved vestibular function. Although other factors such as differing dosages and/or administration routes may also be involved, profound hearing loss associated with the 1555 mutation may be due to a different pathogenic mechanism, i.e., strial dysfunction rather than a direct insult to the hair cells.

Tinnitus suppression by electrical promontory stimulation (EPS) in patients with sensorineural hearing loss

Objective: Almost 10–15% of the population suffer from chronic tinnitus. There are clinical indications that a ‘pathological sound’ may be induced by any level of the auditory pathways. Theraupeutical difficulties and many hypotheses about tinnitus and places from which they originate might indicate various methods of treatment. Electrostimulation tinnitus suppression was achieved by many authors from 22 (Graham, Hazell) to 87% Portman). The aim of our study was to define the usefulness of electrostimulation in treatment of persistent noise induced cochlear lesion tinnitus (group I — 43 men) and compare the results with the non noise induced tinnitus group II (68 patients). Methods: Otolaryngological and audiological examination at the patients was made before and after electrostimulation, and at 90 days. The stimulation system consisted of a prototype tinnitus suppressor, the active platino-iridium needle electrode and silver surface electrode located on the forehead. Transtympanal electrical stimulation was performed using positive polarity direct current. Parameters of electrical impulse were individually different and depended on tinnitus parameters and patients sensation. The current levels ranged from 20 to 600 μA and frequency ranged from 60 to 10 000 Hz. Average time of EPS was 60 s. Results : The control examination 90 days after stimulation in group I showed subjective improvement in 18 (41.9%) patients, 22 (51.2%) did not notice any change and tinnitus deteriorated in 3 (6.9%) of the patients. In the comparative group II improvement was occurred in 34 (50%) persons including 2 (17.6%) in whom tinnitus was abolished, in 30 (44.1%) tinnitus was unchanged and 4 (0.6%) became worse. In both groups our method did not have a destructive influence on hearing. Electrical stimulation to relieve tinnitus have been used for nearly 200 years, but it is unclear how electrical stimulation works to suppress tinnitus. Conclusion: In our opinion electrical stimulation by using positive DC changes the spontaneous activity of cochlear nerve fibres. According to our results it is suggested that the mechanism of beneficial effects is due to increased microcirculation in part of the auditory pathways. Poorer results in patients with noise induced tinnitus could be explained by greater damage of the cochlea outer hair cells. In our opinion EPS could be a method of treatment for persistent tinnitus in cases which fail to respond to other methods.

Auditory-nerve integrity after middle-fossa acoustic-tumor removal

We sought to investigate the functional integrity of the auditory nerve in patients with postoperative hearing loss after middle cranial fossa acoustic-tumor removal in a case-series descriptive study. The study setting was a tertiary referral center, a private otologic practice. The study population comprised seven patients who underwent a middle-cranial-fossa approach for unilateral acoustic-tumor resection and sustained postoperative anacusis with an anatomically intact auditory nerve. Four were men and three women; they ranged in age from 30 to 60 years; all underwent surgery between 1990 and 1994 and agreed to return to the center to participate in the study during 1995. Diagnostic electrical promontory stimulation was used to determine the functional integrity of the auditory nerve. Our main outcome measures were the presence or absence of discrete tone perception, electrical threshold, maximum acceptable level and dynamic range, gap detection and temporal difference limen during electrical promontory stimulation. Three of the seven patients demonstrated positive responses to electrical promontory testing (e.g., discrete tone perception). All three were able to perform the gap-detection and temporal difference limen tests. None of the preoperative characteristics was related to performance on promontory stimulation testing. We conclude that the middle cranial fossa approach permits anatomic—and, in some cases, functional auditory-nerve preservation. These data suggest that auditory rehabilitation in some patients who sustain anacusis after the middle cranial fossa approach to acoustic tumors, as in neurofibromatosis 2, may be provided with cochlear implantation. (Otolaryngol Head Neck Surg 1998;119:588-92.)

Electrocochleographic analysis of the suppression of tinnitus by electrical promontory stimulation.

To investigate the origin, and evaluate the mechanism by which tinnitus is suppressed we performed electrical promontory stimulation (EPS) in 56 patients with tinnitus, and measured the compound action potential (CAP) using electrocochleography before and after EPS. In the group of patients in whom tinnitus was suppressed, the CAP amplitudes increased significantly, whereas the latencies showed no remarkable change. In the group of patients in whom tinnitus was not suppressed, both the CAP amplitudes and latencies exhibited no significant change. These data indicate that the effect on the cochlear nerve plays an important role in the suppression of tinnitus by EPS. The CAP reflects the number of the auditory nerve fibers which discharge synchronously. It is speculated that an increase of the CAP amplitudes is caused by synchronizing discharges of the auditory nerve fibers, and that the mechanism by which EPS suppresses tinnitus may be related to synchronizing these discharges.

Preliminary Study of Improved Perception of Words with the Same Sound but Different Intonation in Tinnitus Patients Following Electrical Stimulation of the Ear

The present study aimed to explain how tinnitus relief following electrical promontory stimulation affects detection of changes in pitch frequency. To determine the effects of tinnitus relief on the auditory system, Japanese words with the same sound but different intonation were used to verify the effects of tinnitus relief on pitch detection in tinnitus patients. Eight out of 11 patients experienced relief of tinnitus following treatment. The averaged number of the ratio in 8 patients with relief of tinnitus, 0.58, was significantly higher (p > 0.02) than that in 3 patients without relief, 0.15. In comparison with averaged hearing level, there was no significant difference in averaged hearing level between 8 patients with relief of tinnitus (52.4 dBSL; SD: 11.4) and 3 without relief of tinnitus (58.0 dBSL; SD: 14.7) (p < 0.68). No significant difference in age between patients with and without relief of tinnitus was observed.

A study of electrical promontory stimulation in tinnitus patients.

Electrical promontory stimulation relieved tinnitus in 74 (57.4%) of 129 ears (112 patients). There was no significant difference in etiology of tinnitus, age, average audiogram, or tinnitus frequency between patients who responded to electrical stimulation and those who did not. Most patients who did not respond to the initial stimulation trial did not respond to the subsequent trials, suggesting that the initial response to treatment predicts the subsequent response. Patients who did not respond to repetitive treatment were supposed to be under severe stress.

極性可変な岬角電気刺激装置による耳鳴治療

This study was designed to evaluate the effectiveness of the suppression of severe tinnitus by the alternating polarity electrical promontory stimulation (EPS) method. The three types of stimulation used in this study were electrical burst (duration 0.5 sec., 1 Hz) of 1) biphasic pulsed AC, 2) pulsed anodal DC and 3) pulsed cathodal DC. In 27 subjects (42 ears), tinnitus was suppressed after EPS in 25 ears (60%), and the effect lasted for more than two days in 12 ears (29%). When anodal DC was applied, some patients complained of severe earache during EPS, but tinnitus suppression after EPS was more frequent and longlasting. We conclude that in spite of rather severe earache occasionally, pulsed anodal DC EPS is more effective than biphasic pulsed AC or pulsed cathodal DC EPS in cases of severe tinnitus.

Tinnitus Suppression by Electrical Promontory Stimulation in Sensorineural Deaf Patients

In 62 patients, whose hearing acuity was normal or profoundly impaired, tinnitus suppression was attempted through electrical promontory stimulation (EPS) with a Promontory Stimulator (Cochlear Co.). The causes of tinnitus were idiopathic sudden deafness, ototoxicity, noise induced hearing loss, labyrinthitis, Meniere's disease, acoustic neuroma and unknown origin. Reduction of tinnitus was achieved in 46 of 68 ears (67.6%). Of these, EPS was most effective in cases of noise induced hearing loss (100.0%; 3/3), followed by those of idiopathic sudden deafness (87.5%; 14/16), Meniere's disease (83.3%; 5/6), labyrinthitis (75.0%; 6/8), ototoxicity (66.6%; 4/6) and unknown origin (76.4%; 13/17). The treatment had hardly any effect on patients with acoustic neuroma (8.3%; 1/12). Twenty patients reported residual inhibition with a duration ranging from several hours to one week. Our results suggest that tinnitus due to cochlear lesions can be suppressed by EPS. This technique may also be useful for differentiation between tinnitus resulting from cochlear lesions and from retrocochlear lesions.

Electrical promontory stimulation in patients with intact cochlear nerve and anacusis following acoustic neuroma surgery.

Anacusis following hearing preservation surgery for acoustic neuroma removal in which the cochlear nerve was preserved has been explained on the basis of neural or vascular compromise. In the absence of pathologic evidence for either theory, a physiologic model was chosen. Electrical promontory stimulation with monitoring of subjective and electrically evoked auditory brainstem responses was undertaken. A positive response to stimulation suggests a vascular impairment of the cochlea sparing the cochlear nerve and spiral ganglion. The absence of response suggests loss of neural integrity at the level of the spiral ganglion or cochlear nerve. Six patients who suffered anacusis following hearing preservation surgery for acoustic neuroma were studied. Data regarding electrical promontory stimulation, auditory brainstem responses, and implications of the possible role of cochlear implantation are discussed.

Effects of Preoperative Electrical Stimulability and Historical Factors on Performance with Multichannel Cochlear Implant

We investigated the relationship between results of preoperative transtympanic electrical promontory stimulation, duration of deafness, postoperative implanted psychophysical results, and postoperative speech and speech sound recognition as indicated by a battery of five tests. Our subjects were 10 patients implanted with the Cochlear Corporation multielectrode implant, 1 year postimplantation, with a minimum of 17 active electrodes programmed in the bipolar + 1 mode. The results indicated that preoperative promontory thresholds, the slope of the threshold function, and the duration of auditory deprivation are excellent predictors of postoperative speech and speech sound recognition in the auditory (processor alone) mode. These results have significant implications for patient selection and counseling.

The Vienna Cochlear Implant Program

The cochlear implant program in Vienna has now gathered 160 patient years of experience with 25 patients who have received an extracochlear implant prosthesis and 31 patients who have received an intracochlear implant prosthesis. The sound processor avoids the transformation of speech into pulses and provides a processed analog broad-band stimulation signal. Approximately one half of the patients are prelingually deaf. The selection criteria include electrical promontory stimulation and acoustic and electrical brain-stem audiometry. The rehabilitation program consisting of counseling, communication training, and auditory training is considered an important part of the program. The results are assessed using the Vienna Auditory Test battery. Sixty per cent of the postlingually deafened patients achieve some open-set speech understanding without lip-reading. Sixty-five per cent of the users show a substantial improvement in aided speech understanding versus lip-reading alone.

Pre-operative appraisal of cochlear implant results by means of electrical promontory stimulation: Preliminary report

A test procedure based on the patient's understanding of acoustic material is presented. The score obtained in this test showed a highly significant correlation with the postoperative score evaluated by independent examiners 4 weeks after stimulator adjustment.