Transcutaneous nerve stimulation (TNS) in tinnitus

Low-frequency (2 Hz) TNS applied distally to peripheral nerves of the upper extremity is known to induce a wide-spread, non-segmental and prolonged relief of pain and an increased microcirculation due to sympatho-inhibition in a number of vascular beds. Such stimulation was administered in 29 tinnitus patients of various etiology. Reduction of tinnitus was encountered in 9 subjects in response to a 45-min TNS-session. The improvement was mainly seen in tinnitus characterized by lower frequencies (125-500 Hz). In 7 of the 9 patients, the tinnitus reduction was associated with improvement of hearing, predominantly in the low-frequency band. The effects were still present after one week following daily stimulation at home. On continued treatment, the effects were found to be transitory in 4 of the patients, whereas the remaining 5 patients are still using the stimulator after 2 to 5 years. It is suggested that the mechanism behind the beneficial effects is increased microcirculation in part of the auditory pathways.