Changes in Tinnitus by Cochlear Implantation:A Parametric Study of the Effect of Single-Electrode Stimulation

Introduction: While cochlear implantation may have a positive effect on tinnitus, it is not effective in reducing tinnitus in all patients. This may be due to different patients requiring different strategies of electrical stimulation in order to obtain a positive effect on tinnitus. It is, therefore, important to identify the most effective stimulation strategies to reduce tinnitus. The simplest possible strategy is stimulation by only one electrode. In this study, we investigated tinnitus suppression by electrical stimulation via a single electrode of the cochlear implant. Methods: We performed a listening experiment in 19 adult participants, who had received a unilateral cochlear implant (CI) because of severe bilateral hearing loss. All of these patients had indicated that they suffered from tinnitus. During a 300-s interval, patients listened to blocks of single-electrode stimulation and rated the loudness of the stimulus and any effects on their tinnitus. The 300-s interval included a block of single-electrode stimulation (duration 120 s). In consecutive intervals, the stimulus differed in its cochlear location (basal or apical), its pulse rate (720 or 725 Hz, 1,200 Hz, and 2,400 or 2,320 Hz), and amplitude (just above threshold or equivalent to moderate loudness). Thus, 2 × 3 × 2 = 12 stimulus conditions were tested in each participant, and each condition was presented only once. During the experiment, the participants promptly rated the loudness of the stimuli and the loudness of their tinnitus on a Visual Analogue Scale (10-point VAS). Results: Significantly more tinnitus reduction was observed with stimuli at a moderate intensity level (30%) compared to stimuli at near-threshold level (18%) ([1, N = 222] = 14.115, p < 0.01). No significant differences in tinnitus levels resulted from the different pulse rates and stimulation sites. Eight participants reported an increase of tinnitus loudness under at least one stimulus condition. Changes in tinnitus loudness were generally minor, and never exceeded 3 points on the VAS. The overall effect of cochlear implantation on tinnitus, that is, the effect with full-array stimulation, was not correlated with the effectiveness of the single-electrode stimulation on tinnitus. Conclusion: In conclusion, the effect of single-electrode stimulation on tinnitus is relatively insignificant in comparison to the effect of full-array stimulation. However, in some individual cases, sustained single-electrode stimulation may be beneficial for tinnitus management

A Prospective Study of the Effect of Cochlear Implantation on Tinnitus

Previous studies have shown diverse and sometimes even contrary results concerning the effect of cochlear implantation on tinnitus and the factors that can influence this effect. The aim of this prospective questionnaire study was to determine the effects of cochlear implantation on tinnitus and explore which factors can influence the effect of cochlear implantation on tinnitus. Forty-four of the patients implanted in our hospital returned 2 questionnaire packages, i.e., one before the cochlear implantation and one 6 months after implantation. Before implantation, 66% of the patients experienced tinnitus. This study shows that cochlear implantation could help to reduce tinnitus and the tinnitus handicap in at least 28% of the patients with preoperative tinnitus. In 72% of the patients the tinnitus remained after implantation. None of the patients developed tinnitus after implantation. A shorter duration of tinnitus prior to implantation, a more fluctuating type of tinnitus, a higher tinnitus handicap prior to implantation, and a round-window surgical approach might have a positive influence on the effect of cochlear implantation on tinnitus, but further research is necessary to confirm these findings. (C) 2019 The Author(s) Published by S. Karger AG, Basel</p

Changes in Tinnitus after Cochlear Implantation and Its Relation with Psychological Functioning

This study retrospectively assessed the prevalence of tinnitus in cochlear implant patients and the changes after implantation in 212 patients implanted between 2000 and 2009. Patients were included at least 6 months after implantation and received 2 sets of questionnaires, one about the situation before implantation and one about the situation after implantation. Mostly standardized questionnaires assessed tinnitus handicap (Tinnitus Handicap Inventory, THI, and Tinnitus Handicap Questionnaire, THQ), tinnitus characteristics, hearing loss (Abbreviated Profile of Hearing Aid Benefit) and anxiety/depression (Hospital Anxiety and Depression Scale). Of the approached patients, 117 completed the full sets of questionnaires and 35 completed a short version. Preoperative tinnitus was reported by 51.3% of these patients, of which 55.6% reported a reduction or cessation of their tinnitus after implantation. However, 8.2% of the patients with tinnitus reported a postoperative deterioration of their tinnitus. In addition, among the patients without pre-operative tinnitus, 19.6% reported the start of tinnitus after implantation. The self-reported change of tinnitus correlated with the pre- and postoperative scores on the THI and THQ. The THQ showed slightly more changes in scores after cochlear implantation compared to the THI. Overall hearing handicap and feelings of anxiety and depression decreased after implantation. In conclusion, tinnitus is reduced after cochlear implantation in an important part of the patients, but in a small part implantation has a negative effect on tinnitus. When tinnitus starts after implantation, the tinnitus handicap is mild. (C) 2014 S. Karger AG, Base