To understand the significance of somatic modulation in our tinnitus clinic patients, we studied 44 non-clinical subjects [from personal contacts] with normal or near normal hearing for their ability to induce tinnitus or modulate any ongoing tinnitus with 28 brief isometric but forceful cephalo-cervical or extremity contractions. While in the low-noise testing room prior to any contractions, 24 (55%) reported ongoing tinnitus [15 (34%) had been previously unaware of any tinnitus]. 79% of these had strong tinnitus modulation. All could change tinnitus loudness (58% increased, 8% decreased, 8% both increased and decreased), 33% pitch and 4% location. Three subjects had unilateral tinnitus and all 3 could decrease the loudness of their tinnitus with some of these maneuvers. These results are similar to our results for the clinical population.
Of the 20 subjects with no tinnitus at the time of testing, 40% developed transient robust tinnitus with at least one of our manipulations.
We conclude that (1) the incidence of somatic modulation is no different in the clinical tinnitus population than the non-clinical population, and (2) generation of tinnitus with somatic maneuvers is common even in people with no tinnitus.
These observations suggest that interactions between the somatosensory and auditory systems are critical in understanding clinical tinnitus.