Frequency (kHz)

0.25

0.5

1

2

4

Average threshold

Preoperative

11.6 ± 6.7

16.7 ± 8.1

15.9 ± 10.1

23.1 ± 11.6

22.6 ± 12.1

16.8 ± 8.0

Postoperative

11.7 ± 7.1

16.0 ± 7.4*

15.2 ± 9.6*

21.0 ± 10.3**

21.9 ± 11.4*

16.0 ± 7.8**

t value

0.44

2.11

2.11

3.04

2.11

3.18

P value

0.66

0.04

0.04

0.005

0.04

0.004