Combination of gaps in noise detection and visual analog scale for measuring tinnitus components in patients treated with repetitive transcranial magnetic stimulation.

OBJECTIVES

We aimed to evaluate gaps in noise (GIN) detection and visual analog scale (VAS) for measuring perceived tinnitus loudness and annoyance caused thereby. We quantified the outcomes and effectiveness of repetitive transcranial magnetic stimulation (rTMS) on chronic tinnitus.

METHODS

Fourteen tinnitus patients with normal hearing underwent a 10 day course of active 1-Hz rTMS to the left region of the temporoparietal cortex. GIN (in which the matched pitch and loudness of tinnitus was used to determine the frequency and intensity of background noise) and VAS was used to assess tinnitus loudness and the extent of annoyance caused thereby. Both ten patients with tinnitus who underwent left temporoparietal sham stimulation and fifteen volunteers with normal hearing without tinnitus participated with GIN detection as a control. Correlations between VAS scores and GIN detection were determined via Spearman's correlation analysis.

RESULTS

The mean GIN thresholds of tinnitus-affected (5.87 ms) ears and the ears of control subjects (4.85 ms) differed significantly. In the tinnitus group, 42.8% (6/14) patients experienced significant reductions in tinnitus annoyance, as assessed by VAS. 71.4% (10/14) patients experienced significant reductions in tinnitus loudness, as evidenced by GIN evaluation. Three tinnitus subjects (21.4%) achieved 30% decrease of the threshold of GIN detection. There was no significant change in GIN detection and VAS scores after sham stimulation. A significant positive correlation was evident between GIN data and VAS scores (r=0.84, p<0.001).

CONCLUSIONS

Gaps in noise detection, combined with VAS scores, affords a promising sensitive method by which to evaluate tinnitus loudness and annoyance. Low frequency rTMS significantly decreased tinnitus after the active, but not the sham, treatment.