Results. There was a significant improvement in tinnitus annoyance for the trauma group (p = 0.05). Other subjective aspects of tinnitus were not significantly affected in either group. Between-subject variability of therapeutic response was considerable. Nevertheless, considering subjective loudness ratings, 4/19 non-trauma participants, and 6/20 trauma participants showed an improvement of 20 percent or better. Considering psychoacoustic loudness estimates, 4/19 non-trauma and 6/20 trauma participants showed a 15 dB (HL) improvement. Evenly dividing each group into high and low responders revealed significant improvement in loudness at 1800 and 2400 mg/day for the trauma high-response subgroup (p = 0.007). No significant improvement was obtained for other subgroups.