Table 2 Sample characteristics over all measurement time points and statistical parameters (mean ± standard deviation); n.d. = not done

Questionnaires

Tinnitus Questionnaire

screening

34.6 ± 16.7

38.5 ± 14.7

t = 0.7; p = 0.480

F = 2.2; p = 0.094

week 7

26.4 ± 13.6

35.8 ± 15.5

t = 1.8; p = 0.077

week 9

22.9 ± 13.0

33.7 ± 15.2

t = 2.2; p = 0.036

week 24

26.5 ± 16.3

33.1 ± 16.6

t = 1.2; p = 0.257

week 7 vs. baseline

t = −4.3; p < 0.001

t = −1.4; p = 0.182

week 9 vs. baseline

t = −5.4; p < 0.001

t = −2.5; p = 0.023

week 24 vs. baseline

t = −3.1; p = 0.008

t = −2.7; p = 0.015

Tinnitus Handicap Inventory

screening

40.9 ± 21.7

47.1 ± 17.5

T = 0.9; p = 0.373

F = 4.4; p = 0.006

week 7

29.3 ± 17.1

44.8 ± 19.9

T = 2.4; p = 0.022

week 9

26.3 ± 17.4

41.4 ± 20.0

T = 2.3; p = 0.027

week 24

27.3 ± 19.9

41.3 ± 21.1

T = 2.0; p = 0.058

week 7 vs. baseline

t = −4.2; p < 0.001

t = −1.3; p = 0.225

week 9 vs. baseline

t = −7.4; p < 0.001

t = −3.3; p = 0.004

week 24 vs. baseline

t = −5.5; p < 0.001

t = −2.3; p = 0.037

Beck Depression Inventory

screening

11.4 ± 8.4

12.3 ± 6.9

t = 0.4; p = 0.732

F = 4.4; p = 0.006

week 7

8.7 ± 7.6

12.5 ± 6.6

t = 1.5; p = 0.135

week 9

6.3 ± 4.8

12.1 ± 6.7

t = 2.9; p = 0.007

week 24

7.6 ± 5.7

13.3 ± 8.7

t = 2.2; p = 0.035

week 7 vs. baseline

t = −2.6; p = 0.019

t = 0.4; p = 0.718

week 9 vs. baseline

t = −3.8; p = 0.002

t = −0.2; p = 0.841

week 24 vs. baseline

t = −2.5; p = 0.024

t = 0.8; p = 0.455

Numeric rating scales

loudness

screening

5.9 ± 2.5

6.7 ± 2.1

n.d.

F = 1.9; p = 0.135

week 7

5.3 ± 2.8

6.6 ± 2.4

n.d.

week 9

5.1 ± 2.6

6.8 ± 2.1

n.d.

week 24

5.1 ± 2.7

7.0 ± 2.3

n.d.

week 7 vs. baseline

n.d.

n.d.

week 9 vs. baseline

n.d.

n.d.

week 24 vs. baseline

n.d.

n.d.

annoyance

screening

6.2 ± 3.1

7.4 ± 2.3

t = 1.3; p = 0.225

F = 2.3; p = 0.087

week 7

5.0 ± 2.7

6.9 ± 2.4

t = 2.2; p = 0.037

week 9

4.6 ± 2.2

7.4 ± 2.1

t = 3.6; p = 0.001

week 24

5.4 ± 2.6

7.2 ± 2.5

t = 2.1; p = 0.045

week 7 vs. baseline

t = −2.3; p = 0.037

t = −1.6; p = 0.110

week 9 vs. baseline

t = −2.5; p = 0.025

t = 0

week 24 vs. baseline

t = −1.5; p = 0.154

t = −0.4; p = 0.683

discomfort

screening

7.1 ± 2.8

7.6 ± 2.0

n.d.

F = 1.9; p = 0.142

week 7

5.3 ± 2.8

7.1 ± 2.3

n.d.

week 9

5.5 ± 2.7

7.4 ± 1.8

n.d.

week 24

5.6 ± 2.9

7.3 ± 1.9

n.d.

week 7 vs. baseline

n.d.

n.d.

week 9 vs. baseline

n.d.

n.d.

week 24 vs. baseline

n.d.

n.d.

distractibility

screening

6.4 ± 2.8

6.6 ± 2.6

n.d.

F = 1.9; p = 0.132

week 7

5.7 ± 3.0

6.8 ± 3.1

n.d.

week 9

5.3 ± 2.8

7.2 ± 2.1

n.d.

week 24

5.6 ± 2.7

7.2 ± 2.8

n.d.

week 7 vs. baseline

n.d.

n.d.

week 9 vs. baseline

n.d.

n.d.

week 24 vs. baseline

n.d.

n.d.

unpleasantness

screening

6.2 ± 2.8

7.0 ± 2.2

n.d.

F = 1.1; p = 0.370

week 7

5.4 ± 2.7

6.9 ± 2.5

n.d.

week 9

5.4 ± 2.5

7.0 ± 2.2

n.d.

week 24

5.4 ± 2.4

7.4 ± 2.0

n.d.

week 7 vs. baseline

n.d.

n.d.

week 9 vs. baseline

n.d.

n.d.

week 24 vs. baseline

n.d.

n.d.