Direct current stimulation of the ear in tinnitus treatment: a double-blind placebo-controlled study

The objectives of the study are assessment of the influence of direct current electrical stimulations of the ear in tinnitus treatment, comparison of the results with placebo group and evaluation of hearing after electrical stimulations. The study comprised 120 tinnitus and sensorineural hearing loss patients (n = 184 tinnitus ears). In group one (n = 119 tinnitus ears) the authors applied a non-invasive hydrotransmissive electrical stimulation (15) of the ear, in group two (n = 65 tinnitus ears)--placebo electrical stimulation. Direct rectangular, positive polarization current was used. The frequency of stimulation was adjusted according to tinnitus frequency. In group two, the authors used similar procedure, but no current was delivered through the active electrode. Evaluation of tinnitus and hearing was conducted. In groups one and two, directly after the treatment, the number of ears with permanent tinnitus decreased considerably. In group one in 40 ears (33.6%) tinnitus disappeared; in group two, tinnitus disappeared in four ears (6.1%). After 30 days, statistically significant changes were observed in group one (p < 0.05), which were comparable with results returned 90 days later (p > 0.05). Changes in group two (after 30 and 90 days) were not significant (p > 0.05). The authors recognized audiometric improvement of hearing (in pure tone audiometry). The application of direct current electrical stimulation of the hearing organ, with current frequencies similar to tinnitus frequencies (selective electrical stimulation), was an efficient method in severe tinnitus treatment. We did not observe a harmful effect of direct current on hearing organ.