Alternating current at the eardrum for tinnitus reduction

The effectiveness of alternating current (AC) stimulus on tinnitus was investigated in 10 patients who reported constant tinnitus in at least one ear. Patients were first screened to determine their responsiveness to electrical stimulation in relation to tinnitus reduction. The responsive patients were then stimulated for a treatment period of at least 10 min, during which time the tinnitus was measured. The AC stimuli (62 Hz to 8000 Hz) were applied to the eardrum of the patients via a specially constructed electrode. Psychophysical measurements (pitch matching, loudness matching, minimum masking level, and loudness and annoyance scaling) of the patient's tinnitus were made before and after electrical stimulation. Minimal masking level was determined and tinnitus scaling was performed during the treatment period. Electrical stimulation was effective in tinnitus reduction in 5 of the 10 patients. These 5 patients reported that the loudness and the annoyance of their tinnitus decreased during the treatment period. These observations were consistent with psychophysical measures of contralateral broadband noise masking. Poststimulation reduction in tinnitus varied in duration among individuals from 40 s to about 4 hr.