Cases n (%)

Controls n (%)

NDI before treatment

10 - 29

12 (52.1)

16 (64)

30 - 50

11 (47.9)

9 (36)

Total

23 (100)

25 (100)

P-value = 0.02

NDI after 3 months

0 - 9

16 (69.6)

7 (28)

10 - 29

7 (30.4)

18 (72)

Total

23 (100)

25 (100)