Table 1 DPOAE amplitudes in dB SPL according to 2f1-f2 in tinnitus patients and control groups

818(f1) 1001(f2)

 Min.–max.

− 8.80 to 12.50

3.90 to 16.30

198.50*

< 0.001*

 Mean ± SD.

7.42 ± 4.87

11.04 ± 2.58

 Median

8.40

11.60

1038(f1) 1257(f2)

 Min.–max.

− 12.80 to 14.90

3.20 to 14.0

223.50*

0.001*

 Mean ± SD.

6.77 ± 5.83

10.95 ± 2.95

 Median

8.25

12.05

1306(f1) 1587(f2)

 Min.–max.

− 9.30 – 15.80

5.90 to 16.50

122.50*

< 0.001*

 Mean ± SD.

5.49 ± 6.18

12.23 ± 2.60

 Median

6.50

12.20

1636(f1) 2002(f2)

 Min.–max.

− 16.10 to 15.0

6.20 to 21.0

189.00*

< 0.001*

 Mean ± SD.

5.56 ± 8.26

12.49 ± 3.50

 Median

8.20

12.10

2063(f1) 2515(f2)

 Min.–max.

− 9.30 to 15.60

8.20 to 19.60

176.50*

< 0.001*

 Mean ± SD.

7.18 ± 6.95

13.77 ± 3.31

 Median

8.95

13.55

2600(f1) 3174(f2)

 Min.–max.

− 7.30 to 16.10

− 5.30 to 17.30

200.50*

< 0.001*

 Mean ± SD.

5.73 ± 6.77

12.14 ± 5.20

 Median

6.20

12.85

3284(f1) 4004(f2)

 Min.–max.

− 9.90 to 15.20

1.0 to 17.10

98.50*

< 0.001*

 Mean ± SD.

5.37 ± 5.57

12.49 ± 3.20

 Median

5.75

12.55

4126(f1) 5042(f2)

 Min.–max.

− 13.0 to 19.40

4.40 to 21.40

271.00*

0.008*

 Mean ± SD.

8.26 ± 7.44

13.15 ± 4.23

 Median

8.35

12.75

5200(f1) 6348(f2)

 Min.–max.

− 18.60 to 11.0

− 21.20 to 12.20

127.50*

< 0.001*

 Mean ± SD.

− 7.92 ± 8.43

4.47 ± 8.24

 Median

− 11.85

7.60