THI scores decreased from 49 to 43 in the treatment group with no change in controls. TENS seemed to be more effective in people with low frequency tinnitus and milder hearing losses.
Mild side effects in eight patients: 4 had dizziness, 3 had headache, and 1 had facial numbness. Side effects disappeared after cessation of treatment.
Although statistically significant the 6.6-point decrease in THI score is not clinically meaningful.
Uncontrolled before and after study, pilot/phase I/safety and efficacy.
VNS decreased band power in the delta (1–4 Hz) and theta (4–8 Hz) bands in subjects who responded to therapy and increased band power in those bands in subjects who did not respond to the therapy. The average difference in band power change between VNS and sham trials in participants with tinnitus was strongly correlated with the THI for both delta () and theta () bands.
For the whole group the average decrease in THI score from the baseline was 11% immediately after the treatment and 12% for the follow-up in comparison with the baseline and therefore was not clinically significant.
Patient 001: redness of the abdominal site and vocal cord hypomobility after the surgery; resolved within 2 weeks. Patient 003: infection (lead and electrode explanted). Patient 004: increased tinnitus symptoms for the first week, ongoing depression requiring medication, hoarseness during stimulation, difficulty tolerating standard settings, depressive episode, and failed suicide attempt.
Post hoc analysis of “drug-taking” versus “non-drug-taking” group: 3 of 5 patients in the nondrug group had clinically meaningful decrease in the THI. Only one patient had improvement of 20 points or more.
Case study. Cross over- paired VNS followed by sham.
EEG: resting state, a significant decrease of relative power in the delta, theta, alpha, beta, and gamma frequency band effects after VNS, suggestive of desynchronization. No difference after sham stimulation.
At 4 weeks: THI reduced by 48% and TRQ reduced by 68%. 14-point reduction on the THQ and 23-point reduction on the TAQ. Sham stimulation: increase in THI of 27% and TRQ of 15%. THQ increase 3% and TAQ increase 9%.
Hoarseness during stimulation, transient left vocal cord hypomobility, and slight inflammation at the abdominal surgical site (last two resolved after 2 weeks). Slight worsening of tinnitus after sham treatment.
Reduction in all bands: usually lower bands go down and alpha goes up, contradictory to other studies.
Pilot study, retrospective. Feasibility and safety study with an open, single-armed study design.
Not assessed.
Not assessed.
Two adverse cardiac events (one severe) were registered but considered very unlikely to have been caused by the tVNS device. Also reported were headache, breathing difficulties, chest sensation, dizziness, subjective hearing impairment, worsening of tinnitus, neck pain, croakiness, and sleeping disorder.
Nevertheless, in the light of the potential of tVNS to modulate conduction system of the heart, ECG recordings are recommended in every study of tVNS in order to obtain further safety data.
Baseline to 24-week reduction in TQ score of 2 points; not significant in either group.
Two cardiac events. Adverse events: tingling sensation, dysesthesia, skin redness and pressure marks at the stimulation sites, painful stimulation, dyspnea of low intensity, and headaches. Chest pain, voice alteration/hoarseness, nausea, arrhythmia, dizziness, transient subjective hearing impairment, neck pain, and numbness.
High dropout rate suggests that a therapeutic tVNS application of several hours per day over a period of 6 months is only feasible for some patients. There was no clinically relevant improvement of tinnitus complaints. Data suggest tVNS to be considered safe in patients without a history of cardiac disease.
Prospective, control group and tinnitus group, comparisons both between control and TI and within TI and stimulation versus no stimulation.
Tinnitus patients differed from controls in the baseline condition (no tVNS applied), measured by both cortical oscillatory power and synchronization, particularly in beta and gamma bands. tVNS induced changes in synchrony.
Changes in synchrony correlated with THI scores, at whole-head beta (), whole-head gamma (), and frontal gamma bands ().
Pilot study, short-term therapeutic trial, before and after study.
Auditory N1m responses: “tVNS on” versus “tVNS off” conditions. tVNS decreased amplitude of the auditory N1m response. Peak latencies remained unchanged.
tVNS plus sound therapy led to improved well-being; WHO 5-point well-being questionnaire mean scores increased from 56 to 76. Mean THI and mini-TQ questionnaires scores decreased significantly.
None reported.
The most significant finding of this study was the MEG demonstration of acute neuromodulative effects of tVNS on evoked auditory cortical responses.
Before and after study with long-term follow-up. No control group.
Not assessed.
Mean THI score reduced from 77 at baseline to 55 at 3 months and 38 points at 42.5 months.
None reported.
All four patients reported that treatment changes their tinnitus sound from an intrusive combination of noises into a single, pleasantly perceived noise.
Transcranial alternating current stimulation (tACS)
There were no significant improvements in the tACS group. A large transient suppressive effect was noted for one comparison group receiving transcranial random noise stimulation.
Cohort study, primary and secondary auditory cortex electrodes.
NA.
Visual analogue scales only.
Some reports of dizziness, altered spatial localisation, and altered hearing. Epileptic seizure in 2 patients after prolonged stimulation with an external stimulator.
Self-reported improvements were noted for a subgroup of patients who had pure tone tinnitus.
