Promontory Stimulation Research Articles

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.

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.

Phoneme recognition by a non-native English-speaking cochlear implantee using the WSP, MSP, and spectra speech processors: A case study

This study presents the performance of a non-native English-speaking adult using the Nucleus 22 Channel cochlear implant. Included are the subject’s (1) history, (2) promontory stimulation results, (3) audiological information, (4) pre- and post-implantation speech recognition test results, (5) post-implantation auditory phoneme recognition using the wearable speech processor (WSP), the minispeech processor (MSP), and the Spectra processor, and (6) the subject’s subjective reports of benefits in terms of communication and social interactions. The subject, a highly motivated and intelligent male who, presented with a profound bilateral, progressive sensorineural hearing loss of unknown etiology, was 59 years old when the right ear was implanted. Prior to implantation the subject was aided in the left ear, but had never been aided in the right ear. The subject’s performance using each of three processors is presented for medial vowel recognition and medial consonant recognition using auditory stimulation only. Results are displayed through confusion matrices generated based on the subject’s responses to these acoustic stimuli. In summary, the vowel and consonant phoneme recognition of a subject with the Nucleus cochlear implant using various processors is presented. Improved phoneme recognition is demonstrated with filter banking versus feature extraction coding strategies.

Vestibular function in cochlear implants--prognostic factors and postoperative damage

Eighteen patients with a 22-channel cochlear implant were evaluated both pre- and postoperatively with vestibular function tests; caloric test and body balance test using stabilometry. Preoperative promontory stimulation results and postoperative psychophysical factors of the cochlear implant showed no correlation with the preoperative vestibular function test results. The results of speech perception tests were not affected by the degree of residual vestibular function in any of the patients. However, for patients with deafness for a period of 10 to 20 years, the degree of the residual vestibular function estimated by the caloric test showed a correlation with the results of speech perception tests, significantly in the consonant recognition score. The results, not of length or the Rombberg ratio, but rather of the area of body sway, showed a correlation with the results of speech perception tests; consonant recognition, in patients with a short duration of deafness. Therefore preoperative vestibular function results may be useful as a predictive factor in postoperative speech perception; consonant recognition, for patients with a short duration of deafness. Reduced results of caloric testing after surgery were found in one of 11 patients (9%) with residual vestibular function. The occurrence of vertigo immediately after surgery was observed in 5 of 18 patients (28%), but this symptom was transient. No change in stabilometry results, pre-versus post-operatively, was observed. Thus, vestibular damage after surgery was considered to be minimal.

人工内耳の予後判定因子

We investigated the relationships among preoperative promontory stimulation test results (threshold, dynamic range and gap detection), duration of profound deafness and postoperative vowel and consonant recognition scores. Twenty-eight profoundly deaf patients were implanted with the Cochlear corporation multielectrode implant programmed in the bipolar+1 mode. 6 months or more later they were re-examined. Only the dynamic range of preoperative promontory stimulation showed a significantly positive correlation with the vowel recognition score. And both vowel and consonant recognition scores tended to decrease with longer periods of profound deafness. To select or counsel patients, we must totally consider preoperative promontory stimulation results and the duration of profound deafness.

Tinnitus suppression by electrical stimulation of the cochlear wall and by cochlear implantation

Some recent studies have reported on tinnitus suppression by electrical stimulation of the cochlear wall and by cochlear implant. In the present study, the degree of tinnitus in cochlear implant candidates was determined and the effects of promontory stimulation and cochlear implantation on tinnitus were investigated. Of the cochlear implant candidates, all of whom were either severely hearing impaired or totally deaf, 87% experienced tinnitus. When electrical stimulation was applied to the cochlear wall (promontory stimulation test), tinnitus was abolished in 23% and improved in 46% of the patients. Thus, electrical stimulation of the cochlear wall effectively suppressed tinnitus in 69% of the patients. Following cochlear implantation, tinnitus was abolished in 35% and decreased in 42%. Thus, intracochlear electrical stimulation was effective for treatment of tinnitus in 77% of the patients. The suppression of tinnitus continued for several hours after the patients switched off the implant device. In 60% of the patients whose tinnitus was suppressed or abolished after the cochlear implant surgery, tinnitus was also suppressed in the contralateral ear.

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.

Pathophysiology of hearing impairment in acoustic neuroma with profound deafness: analysis by evoked otoacoustic emission and promontory stimulation test.

Evoked otoacoustic emissions (e-OAEs) were examined and promontory stimulus test (PST) done prior to tumor removal in 15 cases of surgically proven unilateral acoustic neuroma (AN) with more than 80 dB in pure-tone hearing level. The e-OAEs were elicited by tone-bursts at 1 kHz and 2 kHz, and an interaural difference in pseudothreshold of more than 10 dB was defined as a significant impairment of the cochlear function. In PST, electrical stimulation was applied by a burst mode at 6 stimulus frequencies between 50 Hz and 1600 Hz. The number of stimulus frequencies with a positive response was defined as the PST score. The results obtained were as follows; i) Mean interaural difference in e-OAE pseudothreshold was 16.0 dB at 1 kHz and 8.0 dB at 2 kHz, ii) Positive PST was found in only 40% of the subjects and the mean PST score was 0.93, iii). When the pathophysiology of hearing impairment was inferred from the combination of the findings in e-OAEs and PST, it was found that 33.3% of the subjects had pure cochlear impairment, 13.3% pure retrocochlear impairment and 46.7% cochlear-retrocochlear impairment. It is concluded that analysis of both e-OAEs and PST could clarify the pathophysiology of hearing impairment in AN with profound deafness, which cannot be determined by conventional psychoacoustic tests.

Reliability of the Promontory Stimulation Test for the Preoperative Evaluation of Cochlear Implants: A Comparison with the Round Window Stimulation Test

The electrical stimulatory threshold of the preoperative promontory stimulation test (PST) was compared with the postoperative threshold of the electrode following cochlear implantation. Postoperative results from warble-tone audiometry, the vowel recognition test, the consonant recognition test, and the speech tracking test, which employed a speech processor, were similarly evaluated. In certain patients who responded insufficiently to the PST, an exploratory tympanotomy under local anesthesia was performed prior to cochlear implantation, and stimulatory threshold was measured with an electrode placed directly on the round window [round window stimulation test (RWST)]. No correlation was found between the PST results and the postoperative performance of the cochlear implant. The RWST was determined to be better than the PST in the evaluation of cochlear implant performance.

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.

Patient selection for adult cochlear implantation and its experience

From 1986 to 1992, 61 adults with bilateral profound hearing loss visited our hospital for assessment as candidates for cochlear implantation. The selection process consists of the following steps: 1) taking a clinical history, 2) general otological examinations, 3) pure tone audiometry 4) hearing aid evaluation, 5) promontory stimulation testing and 6) CT scans and MR Imaging of the temporal bone. We informed patients and their families of cochlear implantation as well. Consequently 7 out of 61 cases (11.7%) were selected and underwent multi-channel cochlear implantation. Twenty-eight cases were judged to have better hearing with a hearing aid because of a residual hearing. Twenty-one cases were considered to be inappropriate candidates after informing of the cochlear implant procedure. Needless to say, the promontory stimulation testing and imaging studies are significant in patient selection, however, there was only a few who were excluded by these examinations.

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.

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.

Factors predicting postoperative sentence scores in postlinguistically deaf adult cochlear implant patients.

A sample of 64 postlinguistically profoundly to totally deaf adult cochlear implant patients were tested without lipreading by means of the Central Institute for the Deaf (CID) sentence test 3 months postoperatively. Preoperative promontory stimulation results (thresholds, gap detection, and frequency discrimination), age, duration of profound deafness, cause of deafness, lipreading ability, postoperative intracochlear thresholds and dynamic ranges for electrical stimulation, depth of insertion of the electrode array into the scala tympani, and number of electrodes in use were considered as possible factors that might be related to the postoperative sentence scores. A multiple regression analysis with stepwise inclusion of independent variables indicated that good gap detection and frequency discrimination during preoperative promontory testing, larger numbers of electrodes in use, and greater dynamic ranges for intracochlear electrical stimulation were associated with better CID scores. The CID scores tended to decrease with longer periods of profound deafness.

小脳橋角部腫ようにおける岬角電気刺激検査

Transtympanic electric promontory stimulation (EPS) was first performed by House & Brackmann for the purpose of differentiating between sensory and neural type deafness. There are few reports dealing with EPS in neural deafness. This paper focuses on the accuracy of EPS, with the use of a promontory stimulator (Nucleus Co.), in patients with neural deafess. EPS was used to test 18 ears of 17 patients aged 23 to 63 years (mean 46.0 years). The diagnoses were acoustic neuroma (14 patients) and other cerebellopontine (CP) angle tumors (3 patients). A positive response to EPS was noted in 2 of the acoustic neuroma patients (22%), before surgery and hearing with good speech discrimination was preserved in these patients. A positive response was found in 2 of 2 CP angle tumor patients (100%) before the operation. Of the 7 patients tested with EPS after surgery, all showed a negative response. These results suggest that pressure on the acoustic nerve by the tumors was most closely correlated with the response to EPS.

人工内耳の耳鳴抑制効果

There have been several reports that transcutaneous and transtympanic electrical stimulation and electrical stimulation applied to the promontory can suppress tinnitus. Other papers have assessed of tinnitus reduction in patients with cochlear implants. We investigated preoperative tinnitus in cochlear implant candidates and evaluated the effects on tinnitus of promontory stimulation and of cochlear implantation.Tinnitus was experienced in 90% of cochlear implant candidates. Patients with severely impaired hearing had especially marked tinnitus. Promontory stimulation abolished tinnitus in 22% and reduced it in 50% of patients. The corresponding figures after cochlear implantation were 44% and 39%. The effect continued for several hours after stimulation by the speech processor had been switched off.

Round Window versus Promontory Stimulation: Assessment for Cochlear Implant Candidacy

Electrical stimulation of the cochlea is a part of the preliminary evaluation protocol for cochlear implant candidacy at many centers. Typically, a transtympanic needle electrode is placed on the promontory of the ear under consideration and electrical current is presented to measure auditory percepts and psychophysical-electrophysiologic measures. Since 1984, we have used a ball electrode placed directly on the round window (via a tympanotomy) for stimulation, with 27 subjects being so tested to date. Nine additional subjects have had stimulating electrodes placed on both the round window and the promontory. Seven of these subjects yielded complete data. For measurements of threshold, maximum acceptable loudness level, and dynamic range, promontory testing mean values were higher than round window measurements. However, the differences were not significant.

Promontory stimulation following labyrinthectomy

Promontory stimulation testing was carried out on a series of ten patients who had undergone osseous labyrinthectomy. The thresholds, discomfort levels and dynamic ranges were found to be comparable with a series of ten patients who have subsequently been successfully implanted with the Nucleus 22 channel cochlear implant. These findings suggest that cochlear implantation might be possible in a labyrinthectomized ear.

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.

Myogenic influences on the electrical auditory brainstem response (EABR) in humans

Two cases demonstrating the effects of myogenic artifact on the electrical auditory brainstem response (EABR) when using a promontory stimulation site are presented. Intensity-response functions were obtained in the unparalyzed condition, then repeated after infusion of a neuromuscular paralyzing agent. In both cases, the myogenic response was observed at lower stimulus intensities than the EABR components. As intensity increased, the myogenic responses grew at extremely rapid rates and made any subsequent identification of auditory responses virtually impossible. To alleviate the adverse influence of myogenic components, general anesthesia and a paralyzing agent must be incorporated into the test protocol when acquiring the EABR using a promontory site of stimulation.